STEM Team - College of Engineering

Transcription

Grow
Growing a
STEM Team
How to Create a Gender-Equitable
Engineering Program
for Middle School Students
Edited by Suzanne Sontgerath and Erica Thrall
Developed by the
4 Schools for Women in Engineering Collaboration
Northeastern University
Boston University
Tufts University
Worcester Polytechnic Institute
Evaluated by the
Wellesley Centers for Women
Sponsored by the
National Science Foundation
www.stemteams.org
©2005 by the 4 Schools for Women in Engineering Collaboration. All rights reserved.
ISBN 1-4116-4604-5
This project was made possible by a grant from the National Science Foundation (4 Schools for WIE,
HRD 0217110, Senior Program Director: Dr. Ruta Sevo). Any opinions, findings and conclusions or
recommendations expressed in this material are those of the author(s) and do not necessarily reflect the
views of the National Science Foundation.
Contributors
Northeastern
Northeastern University
Paula Leventman, Director of Women in Engineering Programs,
4 Schools Principal Investigator, ’02-’03
Katherine S. Ziemer, Assistant Professor, Chemical Engineering,
4 Schools Principal Investigator, ’03-’05
Rachelle Reisberg, Director of Women in Engineering Programs
Tracy Carter, Program Coordinator, Masters in Chemical Engineering, ’98
Shannon Ingraham, Program Coordinator, Masters in Chemical Engineering, ’05
Saloni Bhardwaj, Program Coordinator, Masters in Chemical Engineering, ’06
Amanda Funai, Electrical Engineering, ’05
Cheryl Hall, Science Teacher, Grover Cleveland Middle School, Dorchester, MA
Hannah Goon, Science Teacher, Josiah Quincy Upper School, Boston, MA
Mark Knapp, Science Teacher, Josiah Quincy Upper School, Boston, MA
Kim Byrnes, Volunteer Engineer, Raytheon
Boston University
Anna Swan, Research Associate Professor, Electrical Engineering,
4 Schools Co-Principal Investigator
Cassandra Browning, Program Coordinator, Masters of Computer Engineering, ’06
Erica Thrall, Program Coordinator, Masters of Biomedical Engineering, ’06
Megan Lopes, Biomedical Engineering, ’05
Jessica Louie, Biomedical Engineering, ’05
Olga Nikolayeva, Biomedical Engineering, ’05
Diem Tran, Mechanical Engineering, ’06
Ayala Galton, Science Teacher, Devotion School, Brookline, MA
Karen Spaulding, Science Teacher, Morse School, Cambridge, MA
Tufts University
Peter Y. Wong, Research Associate Professor, Mechanical Engineering,
Meredith Knight, Program Coordinator
Karen Panetta, Associate Professor, Electrical and Computer Engineering
Rachel Bill, Computer Science, ’04
Kristina Eckholm, Masters in Civil Engineering, ’05
Sarah Freeman, Mechanical Engineering, ’05
Lisa Goel, Doctorate in Biomedical Engineering, ’07
Hoi Yee Lam, Mechanical Engineering, ’05
Emily Nodine, Masters of Mechanical Engineering, '06
Molly Rice, Mechanical Engineering, ’04
Geeta Padimukkala, Mechanical Engineering, ’04
Emily Shattuck, Masters of Mechanical Engineering, ’05
Anne Sullivan, Biomedical Engineering, ’04
Katie Cargill, Science Teacher, Salemwood School, Malden, MA
Erica Wilson, Science Teacher, Ferryway School, Malden, MA
Cissy George, Volunteer Engineer, Verizon
Masumi Patel, Volunteer Engineer, Verizon
Worcester Polytechnic Institute
Institute
Stephanie Blaisdell, Director, Diversity and Women’s Programs,
Suzanne Sontgerath, Program Coordinator
Terri Camesano, Assistant Professor, Chemical Engineering
Emine Cagin, Electrical and Computer Engineering, ’03
Jessica Coehlo, Civil Engineering, ’08
Gissel Morales, Electrical and Computer Engineering, ’06
Katherine Youmans, Mechanical Engineering, ’04
Connie Boyd, Science Teacher, Forest Grove Middle School, Worcester MA
Angela Lamoureux, Science Teacher, Forest Grove Middle School, Worcester, MA
Robin Scarrell, Science Teacher, Forest Grove Middle School, Worcester, MA
Maureen Carlos, Science Teacher, Doherty Satellite Middle School, Worcester, MA
Hilary, McCarthy, Volunteer Engineer, Intel
Wellesley Centers for Women,
Women, Welles
Wellesley College
Sumru Erkut, Senior Research Scientist and Associate Director
Fern Marx, Senior Research Scientist
Acknowledgements
The 4 Schools for Women in Engineering Collaboration partners gratefully acknowledge the National
Science Foundation's support of this project.
We would also like to thank the following schools in the Worcester, Brookline, Cambridge, Malden,
and Boston public school systems for agreeing to participate in this project: Forest Grove, Grover
Cleveland, Josiah Quincy, Morse, Devotion, Salemwood, and Ferryway Middle Schools. In addition,
we would like to recognize the Boston Latin School for providing us with a valuable control classroom
for our program assessment. We would like to thank the administration and staff at these schools for
assisting us in many ways.
We would like to recognize our industry partners: Intel, EMC, Verizon, and Raytheon, who
demonstrate their commitment to diversity in the engineering workforce by supporting efforts such
as this.
Finally, we would like to thank the following attendees of the WEPAN Workshop who reviewed the
draft manual and gave us helpful feedback.
WEPAN Reviewers:
Nuket Acar, WISE Coordinator, Penn State
Christian Arnold, Program Coordinator, Kansas State University
Ann Bloor, Milwaukee School of Engineering
Cindy Campos, Relations Manager, University Relations, Lockheed Martin Co.
Mesa Davis, Hrad Student President, UTAustin
Helen Edson, Program Manager, Pennsylvania State University
Ivan Favila, Director, Minority Engineering Program, University of Notre Dame
Lisa Gable, Manager, IBM
Mary Goodwin, Engineering Undergrad Programs, Iowa State University
Janice Grackin, Research Assistant Professor, Psychology, Stony Brook University
Susan Grefe, Head Guidance Counselor, Taunton High School
Rhonda Heakin, Chief Engineer of Product Design, The Tinken Corporation
Jessica Heier, WESP, Kansas State University
Kim Jackson, MUSES-Minority Women Engineering Organization, University of Michigan
Cheryl Knobloch, Associate Director, WEP, Penn State
Luiza Laniewski, Campus Relations Manager, LMCO
Glenda LaRue, WIE Director, Ohio State
Tamara McCarran, Manager of WISE, University of Calgary
Jennifer McDaniel, Director of Women, University of Central Florida
Joy Oguntebi, Grad Student, University of Michigan
Carol Petri, Associate Director, USTA/PREP, University of Texas San Antonio
Richard Pollard, Pre-College Educator, University of Minnesota
Emma Seiler, K-12 Outreach Coordinator, Mississippi State
Alice Seneres, Grad Student, Rutgers
Paige Smith, WIE Director, University of Maryland
Carol Stwalley, Associate Director of Counseling, Purdue University
C. Denise Wagner, Assistant Professor, Tri-State University
Mary Jo Wellenstein, Assistant Director of Counseling, Milwaukee School of Engineering
Sarah Womack, Grad Student, University of Michigan
Sandy Wood, Director of Freshman Program, University of Alabama
Table of Contents
Introduction
1
Chapter One: Root of the Problem
2
Chapter Two: STEM Team Approach
4
Chapter Three: Program Evaluation
10
Chapter Four: Developing Curriculum Units
11
Chapter Five: Curriculum Units
13
Introduction to Engineering
14
The Great Orange Juice Squeeze
20
Solar-Powered Chocolate Factory
132
Binary and Communication Systems
169
Simple Circuits
193
Wacky Shoes
200
Bridges Connecting Our World
206
Broken Bones
231
Making Bacteria Glow
253
Chapter Six: Suggested Resources for Further Information
271
References
272
Appendices
A: 4 Schools for WIE Partnership Agreements
274
B: Initial Training Worksheets
277
C: Evaluation Tools
292
D: STEM Team Contract
316
E: Sample Manual Format
318
Introduction
Purpose of the Manual
About the Program
The 4 Schools for WIE STEM Team Program is an
innovative way to counteract many of the factors
discouraging young women from entering the
engineering workforce. Research has shown that young
women are drawn to careers that allow them to help
people, that they benefit from positive role models, and
that their perceptions of technical careers are often
shaped by their classroom teachers.
The STEM Team program provides hands-on
engineering activities designed to emphasize the helping
aspects of engineering while providing middle school
students and teachers with female role models. Through
the program, middle school science teachers have an
opportunity to interact with practicing engineers and
explore engineering concepts, which increases their own
confidence and ability to successfully introduce their
students to engineering and engineering-related careers.
In addition, the curriculum units and activities have
been designed to meet state and national standards for
science, technology, and engineering.
This guide is a compilation of the best practices of
the 4 Schools for WIE STEM Teams over a two-year
implementation of the program in seven partner schools.
Each institution created a STEM Team, trained the
team, developed curriculum units, and implemented the
units in middle school science classrooms. An
assessment tool measured male and female students’
attitudes toward math, science, and engineering before
and after the program.
The purpose of this guide is to show other
institutions how to develop an effective STEM Team
program. This guide provides several curriculum units
that have already been piloted in middle school
classrooms. The units can be used exactly as they are
written or as a template for developing new lessons.
Additionally, this guide contains an evaluation
instrument that can be used to assess the effectiveness
of a new program.
4 Schools for Women in Engineering (4 Schools for
WIE) is a collaboration of four main partner
institutions—Northeastern University, Boston
University, Tufts University, and Worcester Polytechnic
Institute—and an evaluative partner— the Wellesley
Centers for Women at Wellesley College. Each of the
main partner institutions has an accredited engineering
program and a strong record of K–12 outreach
programs. The Wellesley Centers for Women has done
extensive research on the development of women in
science and technology.
The four partner universities have developed a
unique intervention system called the STEM (Science,
Technology, Engineering, and Math) Team. One STEM
Team has been created at each institution. The STEM
Team is an all-female team of highly specialized
professional engineers, engineering faculty, engineering
students, and middle school teachers. Each team
member brings her own area of expertise to the
collaboration. The STEM Team develops engineering
curriculum units to be used in middle school science
classrooms. These units are designed to be gender
neutral and meet the Massachusetts Curriculum
frameworks for Science and Technology/Engineering.
STEM Team members present curriculum units in the
classroom and provide female engineering role models
for middle school students. The results of the evaluation
of this program can be found at www.stemteams.org.
Lessons learned from the project can now be
assembled and disseminated to other colleges and
universities. A similar process for developing STEM
Teams and gender-inclusive activities can be used for
other state science and technology frameworks.
Moreover, as more states adopt engineering explicitly in
their frameworks, STEM Teams can help meet the
needs for curricula development.
1
Chapter One:
Issues in Gender Equity
Root of the Problem
Engineering As a Helping Profession?
Women in the United States tend to choose professions
that they believe are “helping” in nature.7,8 These
include professions that help people, animals, or the
environment. The relationship between engineering and
its impact on society has not been well communicated,
and as a result, many students do not perceive
engineering as a helping profession.9
Sue Rosser, in her book Female Friendly Science,
argues that “ensuring science and technology are
considered in their social context may be the most
important change that can be made in science teaching
for all people, both male and female.”10 Clifford
Adelman, a senior research analyst at the U.S.
Department of Education, states that engineering would
be more attractive to women if the ways in which it is
relevant to the real world were part of the education
frameworks.11 More young women would choose a
career in engineering if they believed this career choice
would have a positive impact on their own and other
people’s lives.
Background
Women currently make up approximately 9 percent of
the total engineering workforce in the U.S.1 Although
women represent 57 percent of all undergraduate
students in the U.S., they are only 19 percent of all
undergraduate engineering majors.2, 3 In terms of
advanced degrees, 21 percent of all masters degrees and
16.5 percent of all Ph.D.s in engineering in 2000 to
2001 were granted to women.2
This gender disparity continues to be a pressing
issue for employers, institutions of higher learning, and
the government. Without a diverse workforce, the
quality of technological products is jeopardized, as is
the ability to compete globally. According to the
Congressional Commission on the Advancement of
Women and Minorities in Science, Engineering, and
Technology Development, unless the science,
engineering, and technology workforce becomes more
representative of the general U.S. workforce, the nation
will undercut its own competitive edge in the future.4
Diversifying the workforce is crucial to success.
Studies have indicated that in the U.S. there are
several major factors associated with women’s low rates
of entry into the engineering workforce. Research has
documented that middle school aged girls experience
decreased interest and diminished confidence in math
and science. This leads to inadequate preparation for
higher level courses that are a prerequisite to studying
engineering.5 Other crucial factors include few female
role models and a perception by young girls, and also
society at large, that the field of engineering is one in
which women do not belong. In addition, a recent
survey conducted by the American Society for
Engineering Education reports that although teachers
believe incorporating engineering concepts into their
classrooms is important, they also believe that
engineering is less accessible to their female and
minority students than other career paths.6 Therefore, it
is critical that we develop programs that impact the
attitudes of not only students but also teaching
professionals.
Middle School Years: Losing Interest in Math
and Science
Research suggests that middle school is a crucial
intervention point for encouraging girls to pursue math
and science-related fields.12 As early as the seventh
grade, boys plan to study more math than girls do. From
sixth through twelfth grades, there is an overall decline
in both male and female students’ liking and enjoyment
of math. Students report that math becomes more
difficult in middle school; they receive less support
from parents, teachers, and peers; and they become
more anxious about studying math. More female
students report that math is difficult than do male
students, and more females rate themselves as anxious
in quantitative situations than males, even though their
math ability is approximately equal.13 High school girls
perceive math to be less useful than boys do.14
Through outreach programs such as the STEM
Teams initiative, students are exposed to engineering,
science, and mathematics activities that are presented in
a real-world context. Helping students identify the value
of these subjects will sustain their interest for a longer
period of time.
2
During the middle school years, girls often begin to
perceive fields such as math and science as masculine
and do not consider these subjects as useful to
themselves, their future career aspirations, or the good
of society.16 This perception of math and science as not
relevant may cause some girls to opt out of higher-level
math and sciences courses. Self-selection of these
higher-level courses begins in the eighth or ninth grade.
The focus on encouraging girls to continue in math
and science has had some success. Thanks to outreach
programs such as STEM Teams, girls are taking more
math and science courses and are performing as well as
boys on most standardized tests.17,18 However, girls are
still not choosing to study engineering. Research
suggests that connecting girls with female role models,
providing them with hands-on science and math
activities that introduce the “helping” nature of
engineering, and offering professional development for
teachers may help encourage girls to consider careers in
engineering.19
Gender-Equitable Classrooms
Teachers play a critical role in both educating students
about engineering as a career option and in creating an
equitable learning environment for girls.29 The
American Association of University Women report
“How Schools Shortchange Girls” states that boys tend
to receive more attention and praise from teachers than
girls do.30 In addition, classroom activities are often
tailored to boys’ interests and learning styles rather than
to girls.31,32 Girls tend to prefer a non-competitive,
cooperative learning environment based on group work
rather than on competition.33,34 To ensure an equitable
classroom, the curriculum and teaching style must
reflect the interests and social roles of both genders.35
Teachers and guidance counselors also must be aware of
their ability to encourage girls to consider engineering
as a potential career.
National and State Standards
Standards
Making the Case for Role Models
In addition to the goal of creating a more diverse
workforce, educating students and teachers about
engineering addresses current national and state
education standards that emphasize science and
technology. These national standards state the following
about the goal of the science and technology component
for grades 5 through 8:
Engineering and science are traditionally viewed as
masculine occupations.20 Women are consistently
absent from children’s drawings of scientists, as well as
children’s drawings of engineers.21 In fact, when asked
to draw an engineer at work, many students draw
pictures of male car mechanics and construction
workers. The small number of women in the
engineering profession results in a lack of available
female engineer role models. These “missing” role
models are a major factor in the gender disparity in
engineering fields.
The influence of a role model has been identified as
a significant factor in career choice among women.22 A
lack of female role models makes it difficult for young
women to imagine themselves in engineering careers,
limits opportunities to “learn by watching,” and affects
a woman’s career development and choices. This may
have its most serious effect in reducing women’s
perceived field of options.23 Many women who have
persisted in STEM fields identify an influential person
who played a key role in influencing their decision to
enter a technical field. In the Women’s Experiences in
College Engineering (WECE) Project conducted by the
Goodman Research Group in 2002, 10 percent of the
female college students surveyed mentioned that others
had encouraged them to become engineers. Of the nonparental mentors in this group, about one-third of them
were engineers, and those who were not engineers were
often math or science teachers.24 Although males can be
role models to girls, female role models are more
effective.25 The presence of role models can help
encourage girls’ attitudes towards careers in science,
math, and technological fields.27,28
In the middle school years, students’ work with
scientific investigations can be complemented by
activities in which the purpose is to meet a human
need, solve a human problem, or develop a product
rather than to explore ideas about the natural world.
The tasks chosen should involve the use of science
concepts already familiar to students or should
motivate them to learn new concepts needed to use
or understand the technology.36
The Massachusetts Curriculum Assessment System
(MCAS) was established in 1998. Students are tested in
three areas of proficiency—English, mathematics, and
science and technology/engineering. Test results are
used for improvement in teaching and learning as well
as school and district accountability. Originally, scaling
of the assessment consisted of mathematics and English
components only, but in 2002 the science and
technology/engineering portion of these standards was
adopted as a scaled measure of the exam. Current
students in Massachusetts must be proficient in the
mathematics and English portions of the exam to
receive a high school diploma. By the spring of 2006,
they will also have to pass the exam in one of the
following science and technology disciplines: biology,
chemistry, physics, or technology/engineering.37
3
Figure 1. STEM Team Model
Chapter Two:
STEM TEAM
STEM Team Approach
There are two main elements to the STEM Team
model—the all-female makeup of the team and the
collaboration between middle school teachers and
engineers. As previously noted, engineering is
traditionally viewed as a male profession. The 4 Schools
for WIE STEM Team program uses a female team in an
effort to challenge this stereotype and have a positive
impact on female students by providing female role
models. Introducing both male and female students to
female engineers may help change the culture in STEM
disciplines.
In order to have a maximum impact on both male
and female middle school students, the students should
be told that they will be visited by a “group of
engineers” with no initial reference to gender. Calling
attention to the gender of the STEM Team prior to their
interaction with students could undermine the impact of
unexpectedly seeing a team of female engineers.
The second critical element of the STEM Team
model is the collaboration between middle school
teachers, professional engineers, engineering professors,
and engineering students. One of the obstacles to
educating students about technology is the inadequate
preparation of teachers.38 Teachers who are trained in
traditional institutions receive little or no education
about engineering. The STEM Team partnership leads
to a valuable cross-training among the team members.
Teachers have the opportunity to gain a deeper
understanding of engineering concepts and the
engineering profession, while engineers have an
opportunity to gain insight into the middle school
environment.
Industry
Partner
• Corporate
support
• Volunteer
engineers
University
Partner
• Program
coordinator
• Students
• Faculty
School
Partner
• Administration
• Teachers
• Middle school
students
University Partner
The university or sponsoring institution is the lead
partner on the STEM Team. As lead partner, the
university can ensure that the process of collecting data
and reporting results will be
Undergraduates
reviewed by an Internal Review
at WPI received
Board for Human Subject
project credit for
participating in
Research. This is important
and reporting on
because the funders and all
this program.
partners are interested in seeing
outcomes, but the rights of the
students and other stakeholders must be protected.
If the team is not externally funded, the institution
should be prepared to fund the position of program
coordinator and provide release time for a faculty
member. The university partner should be prepared to
contribute the following to the STEM Team: financial
support, personnel, and undergraduate students.
Recommended Financial Contributions from
University
• Salary of program coordinator
• One-month summer salary for
An industry
partner may
faculty
provide funding
• Cost of supplies for
for teachers and
engineering activities
undergraduates.
• Substitutes for teachers while
they attend meetings
Creating the STEM Team
STEM Team Model
The structure of the individual STEM Teams may vary
from institution to institution. The 4 Schools for WIE
collaboration suggests the model in Figure 1 for the
STEM Team. This model includes the level of
commitment by each of the partners, as well as
individual time and financial commitments. Volunteer
engineers should be recruited from a variety of
engineering fields and ethnic backgrounds.
Optional
• Stipends for teachers
• Stipends for undergraduate students
Recommended Personnel at University
• A program coordinator acts as the main administrative
person on the team. She maintains all documentation,
budgets, and team schedules. The program coordinator
is the main liaison between the institution, the
participating school, and the team members. The
number of hours required for program coordination
will vary depending on the coordinator's background.
If the program coordinator is an engineer or has a
4
STEM background, she may also participate in the
classroom.
• An engineering faculty member lends technical
expertise to the team. The faculty member may help
generate content and participate in the classroom.
• Engineering undergraduate and graduate students help
out in the classroom and serve as role models. The
number of undergraduate students on the STEM Team
will vary from team to
team. Students with
Two problems with
diverse ethnic
sending students
backgrounds and from
into the classroom
different engineering
include lack of
disciplines should be
teach
experiience
teac
hing exper
encouraged to
sched
and hectic sche
dules.
participate. If funds are
available, students may
be reimbursed for their time. One value associated
with student team members is their ability to relate
more closely to middle school students, due to their
relative youth.
Industry Partner
Industry partnerships vary depending on the level of
involvement of the corporation. At a minimum, the
industry representative should be released from
corporate duties in order to attend STEM Team
meetings, take part in training sessions, and volunteer in
the classroom. In return, industry partners should be
recognized on all team documents.
Recommended Financial Contribution from
Industry Partner
• Provide some or all of the funding for the team
• Provide stipends for students
• Offer incentives to encourage employees to volunteer
Recommended
Personnel from
Industry Partner
• Engineers (preferably
female) who can attend
training sessions, help
develop curriculum, and
interact with students
Benefits of Participation for University
• Community outreach
• Increase in the engineering pipeline
• Volunteer opportunities for faculty and students
• Teaching experience for undergraduates
Industry representa
representatives
currriculum
supported cu
development,, volu
volun
development
nteered
clas
rooms,
in cla
ssroo
ms, or gave a
company..
talk about their company
Benefits of Participation for Industry Partner
• Opportunity for employees to do community service
• Opportunity for individual female engineers to help
make a difference for future generations
• Opportunity to promote a positive image of the
corporation in the community
• Opportunity to assist in diversifying the future
workforce
School Partners
The size of the STEM Team and the resources available
will determine whether it is best to partner with one or
more schools. Middle schools should allow STEM
Team members access to their classrooms, cooperate
with evaluations, release test scores if required to
validate the program, and provide substitute back-up
while middle school teachers attend STEM Team
meetings and trainings.
Table 1 shows the expected time commitment for each
of the individual STEM Team members listed above.
(These times are estimates based on the assumption that
each team works with a maximum of three middle
school teachers.)
Recommended Financial Contribution from School
• None (program is meant to benefit the school)
Recommended Personnel at School
• Middle school science teachers (preferably female)
willing to help develop an engineering curriculum
Table 1: Time Commitment for STEM Team Members
Benefits of Participation for School
• Materials for activities are supplied by the sponsoring
institution.
• Teachers are sponsored by the university or industry
partner.
• Substitutes are provided while teachers attend training
sessions.
• Visiting female engineers serve as role models for
middle school students.
• Teachers and students receive assistance with MCAS
or other state and national engineering frameworks.
STEM Team Member
Time Commitment
Program Coordinator
20 hours per week
Engineering Faculty
100-150 hours per
school year
Undergraduate or
100-150 hours per school
Graduate students
year
Middle School Teachers
50 hours in addition to
Industry Representatives
Varied from 5-150 hours
classroom time
5
4 Schools for WIE suggests obtaining signed
partnership agreements with both the partner school
district and the industry representative. Examples of
partnership agreements can be found in Appendix A.
Table 3: Costs Associated with Activities
Activity
Cost Per
Class Periods
Class of 25
(45-minute)
Administration
Administration of the STEM
Introduction to
Team
2
Students
Less than $10
Engineering
Great Orange
Solar Chocolate
The following are some costs that may be associated
with having a STEM Team program at your institution:
$300
10
$160
Factory
Binary and
Salaries will vary from institution to institution. For
budgeting purposes, the following table lists salary
considerations associated with different team
members.
7
$20 (for
Communication
Internet-based
Systems
box), $600 (for
6 preassembled
binary boxes)
Table 2: Salary Considerations for STEM Team Members
Hours
25
Juice Squeeze
Cost of the Program
Position
Number of
Salary
Simple Circuits
2
$30
Wacky Shoes
2
Less than $30
(if bringing
Required
supplies from
Program
20 hours per
Depends on
Coordinator
week
institution
Bridges
Engineering
100 – 150
One month
Connecting the
Faculty
hours per year
summer salary
World
Undergraduate
100 – 150
Credit or hourly
Broken Bones
Students
hours per year
wage
Middle School
5 hours per
Depends on
Teachers
week
institution
home)
Making Bacteria
8
$20-$30
7
$20-$30
10
Glow
$165 (for pGLO
lab only)
Scheduling Classroom Visits
Stipends: Teachers receive a stipend for participation.
Students may receive an hourly wage for
participation.)
Substitutes: Substitutes should be hired for school
teachers who attend meetings.
Evaluation: If you receive external funding for your
program, you may need to have it evaluated by an
external evaluator.
Supplies: The cost of supplies will vary depending on
the activities and their complexity. The table below
shows the average costs per class associated with the
activities developed by the 4 Schools for WIE STEM
Teams.
Scheduling is one of the most time-intensive aspects of
this program. The curriculum units are designed so that
teachers can use them without the assistance of
practicing engineers or engineering students. However,
to ensure that middle school students have exposure to
engineering role models, STEM Team visits to the
classroom are highly recommended.
The program coordinator should work closely with
the teachers and the engineers to develop a schedule that
meets everyone's needs. Each curriculum unit will
require a different number of classroom visits. We
suggest that at least two volunteers are present in the
classroom at any time to work with students.
6
Training the STEM Team
Copies of worksheets and handouts associated with
these 13 individual training sessions can be found in
Appendix B.
The first step in mentoring
train
The ssecond
econd trai
ning
students and creating a
gender-inclusive curriculum
session is more
is to ensure that all team
affter the
valuable a
members are well versed in
team has been in the
the areas of gender equity,
sev
classroom se
veral
classroom environment,
times and has had
assessment techniques, and
experience with
engineering curriculum unit
stu
st
udents.
development. We suggest
that each STEM Team undergo an initial training
session at the onset of the program to cover the
following areas:
1. Technological literacy
2. Review of your state's assessment system for science
and technology/engineering (in Massachusetts:
MCAS)
3. Creating effective engineering projects
4. Gender equity issues
5. Assessment techniques
6. Curriculum unit development
We recommend a second training session to further
explore issues surrounding gender equity and girls in the
classroom.
1. TECHNOLOGICAL LITERACY: STATE
STANDARDS AND ENGINEERING
FRAMEWORKS (suggested time: 30 min.)
Part One: Technological Literacy
Lead a discussion on the National Academy for
Science report “Technically Speaking” (available at
www.nap.edu/catalog/10250.html). This report states
that Americans need to become more technically
literate and understand technology. Discuss the
characteristics of a technically literate person as
defined by this report.
A technically literate person should
• be familiar with basic concepts important to
technology;
• know something about the engineering design
process;
• recognize that technology influences changes in
society and has done so throughout history;
• recognize that society shapes technology as much
as technology shapes society;
• recognize that the use of technology entails risk;
• understand that all technologies have benefits and
costs that must be weighed;
• recognize that sometimes not using technology
has risks;
• appreciate that technologies are neither good nor
evil;
• have some hands-on capabilities with common
everyday technologies;
• and be able to participate in debates about
technological matters.39
Initial Training Sessions
Figure 2 shows the suggested schedule for training
sessions for a new STEM Team. Individual training
sessions that have been used to successfully train a new
STEM Team are discussed below.
Figure 2: Suggested STEM Team Training Schedule
STEM Team Training Schedule
Day One
Day Two
Day Three
Day Four
Getting to
Know You
Session
Session 4:
Types of
Session 8:
Startling
Session 12:
Creating a
Activity
Engineering
Statements
Rubric
(30 min
minutes)
(45 min
minutes)
(45 min
minutes)
(150 minutes)
Session 1:
Session 5:
Session 9:
Session 13:
Technologi
Technological
Literacy
Cur
Curriculum
Unit Planning
Classroom
Classroom
Strate
Strat
egies for
Expectations
for Volunteers
Training
(30 min
minutes)
Gender Equity
Equity
(45 Minutes)
(30 min
minutes)
Note: The person leading this discussion should
have read and be familiar with “Technically
Speaking.” It would be helpful if training
participants have read some or all of the report.
Part Two: State Standards and Engineering
Frameworks
invitting a
Discuss curriculum
Consider invi
frameworks associated with
member of the
your partner school district.
Commis
State Commi
ssion
This may include district,
Educ
duca
on E
duc
ation
state, and national
Frameworks to talk
frameworks. Distribute copies
to the STEM
of the frameworks to all
Teams.
STEM Teams and discuss
them.
(90 min
minutes)
Session 2:
Models for
Session 6:
Role of Failure
Session 10:
InquiryInquiry
-Based
Effective
(75 min
minutes)
Learning
Design
(60 min
minutes)
(120 min
minutes)
Session 3:
Session 7:
Session 11:
Engineer
ngineering is
All Around Us
Curriculum
Planning
Unit Plan
ning
HandsHands-On,
Inquiry-Based
Inquiry
(60 min
minutes)
(150 minutes)
Learning
(60 min
minutes)
7
review existing curriculum units for style and content.
The team should then brainstorm a project that is
appropriate for the classrooms they are working with.
(Use the Challenge Project Worksheet in Appendix B
as a guide.)
2. MODELS FOR EFFECTIVE DESIGN: SOLAR
ROOM DESIGN PROJECT (suggested time: 120
min.)
Ensure that all members of the STEM Team are
familiar with the engineering design process, which
includes the following eight steps:
• Identify the problem
• Research the problem
• Develop possible solutions
• Choose the best solution
• Develop a prototype
• Test and evaluate the solution
• Communicate the solution
• Redesign the solution
Workshop leaders should use the handouts provided
to review the design process with the teams. Teams
will then be given a design project to complete. Each
team will use the engineering design process to
brainstorm and build a prototype solution to a specific
problem. Suggested project ideas can be found in the
appendix.
Input from teachers is critical at this juncture to
ensure that units meet the needs of the existing
science curriculum. There is very little room in
teachers' schedules for units that do not meet existing
curriculum needs.
Note: If you are not going to develop individual units and
plan to use only the units contained in this manual, this
session and session 9 of the training may be eliminated.
6. ROLE OF FAILURE (suggested time: 75 min.)
Discuss the concepts of failure as a critical component
of the engineering design process. Show a video that
emphasizes examples of engineering failures. (For
example, you could show the History Channel’s
Modern Marvels episode “Engineering Disasters,”
which can be ordered from Amazon.com.)
Note: This is the first opportunity for the STEM Team to
work together and begin to recognize its strengths and
weaknesses. Call attention to this fact during the training.
7. CURRICULUM UNIT PLANNING TIME
(suggested time: 120 - 150 min.)
3. ENGINEERING IS ALL AROUND US
(suggested time: 60 min.)
This can be done in one session or broken down into
several individual sessions. This is an opportunity for
the STEM Team to refine their original project
concept developed in Session 5 and outline a
curriculum unit. (Teams should use the Challenge
Project Worksheet in Appendix B as a guide during
these sessions.)
Introduce STEM Team members to the concept of
using resources that may be readily available (either
at your institution or within the community) to assist
in the development or presentation of engineering
activities. Discuss with the group resources they may
already use or other resources that should be
explored. Some resources to consider include the
following:
• Laboratories and faculty at your institution
• Area companies producing interesting products
• Local nonprofit institutions
• Science museums
Note: Having additional engineering faculty available to
the STEM Teams during this portion of the training
would be a valuable resource.
8. STARTLING STATEMENTS (suggested time: 45
min.)
Invite a guest speaker to talk about issues of gender
disparity in the engineering workforce. If no one is
available, use the background information found in
Chapter One of this manual.
4. TYPES OF ENGINEERING (suggested time: 45
min.)
Introduce STEM Team members to the various
engineering disciplines with a slide presentation.
Many resources are available to help describe the
disciplines, including several engineering society
websites. Use examples from the real world that the
audience can relate to.
9. CLASSROOM STRATEGIES FOR GENDER
EQUITY AND GENDER EQUITY CRITERIA
Discuss strategies for creating a gender-equitable
classroom. Use the “Gender-Equitable Practices”
worksheets in Appendix B8 to explore strategies for
creating equitable classrooms. These worksheets were
developed by Wellesley Centers for Women. The
strategies provided encourage teachers to share
techniques they are currently using in their own
classrooms and to explore areas they feel might be
5. INTRODUCE CURRICULUM UNITS
Now that the team is familiar with the state
frameworks, the types of engineering, and the
engineering design process, it is time to begin
developing a curriculum unit. Encourage the team to
8
lacking. Use the worksheet “From Equity, Excellence,
and Just Plain Good Teaching” to consider criteria for
a gender-equitable science activity and how these
criteria may be different for an engineering activity.
Discuss the “Guidelines for Creating GenderEquitable Engineering Activities” found in Chapter
Four of this manual and create your own STEM Team
guidelines.
• Teaching: How involved will the teacher be in
classroom management? How much will the
teacher prepare students in advance? How does
the lesson fit in the overall curriculum?
• Appearance: What is the dress code for
undergraduate student volunteers?
Second Training
Training Workshop
A second team training workshop should be conducted
after the team has spent time in the classrooms. The
following is a suggested format for the second training:
1. Ice Breaker Activity (Optional)
Use a traditional ice breaker activity to encourage
team members to interact.
2. Gender Issues in the Classroom
This should build upon the information presented in
session 9 of the initial training. Team members can
now better identify their strengths and weaknesses
in delivering gender-equitable curriculum.
3. Gender-Equitable Engineering Activity
To reinforce the concepts of what constitutes a
gender-equitable activity, have the STEM Team
members work on a hands-on design activity that is
gender-equitable, such as the Wacky Shoe activity
provided in this manual.
Note: For a more extensive training session on gender
equity, visit the Wellesley Centers for Women website at
www.confidentgirls.org and look for the article “Raising
Confident and Competent Girls.”
10. INQUIRY-BASED LEARNING (suggested time:
60 min.)
Invite an educator to discuss inquiry-based learning.
This would preferably be a science teacher or other
teacher who has experience leading hands-on projects
in the classroom.
11. BUILDING BALANCES: HANDS-ON
ACTIVITY (suggested time: 60 min.)
Use a hands-on engineering design activity to
reinforce the concepts of inquiry-based learning. One
such activity, “Lego Balance,” is provided in
Appendix B6.
12. CREATING A RUBRIC (suggested time: 150
min.)
Working as a Team
This session on assessment is especially valuable to
the non-teaching members of the STEM Team, such
as engineering students, industry representatives, and
program coordinators. Introduce and discuss different
methods and qualities of authentic assessment. (See
“Qualities of Authentic Assessment,” in Appendix
B9.) Explain to team members the method for linking
assessment to the standards. (Use the “Linking
Standards to Assessment Handout” handout found in
Appendix B10.) Show examples of rubrics tied to
current science and engineering activities.
Development of Curriculum Units
Curriculum units are developed by the STEM Teams in
several stages:
• Discussion of initial concept and outline during
team training
• Development of activity during team meetings
• Write-up of student directions and teacher’s
manual before classroom visit
• Presentation of unit in classroom
• Redesign unit based on feedback from students,
teacher, and classroom volunteers
13. Expectations for Visiting Volunteers (suggested
time: 45 min.)
More information on designing your own curriculum
unit, as well as copies of the units developed by the 4
Schools for WIE STEM Teams, can be found in
Chapters Four and Five and on the website at
www.stemteams.org.
Use this session to give teachers an opportunity to
express their expectations when guests visit their
classroom. Issues to consider:
• Language: How does the teacher wish to be
addressed? How should guests be addressed?
• Environment: What type of behavior do teachers
expect from students? What type of behavior
should guests expect from students?
• Time: How long will volunteers be in the
classroom?
9
Chap
Chapter Three:
Qualitative Surveys of STEM
Program Evaluation
Team Members
Potential assessment measures for a STEM Team
program could include the following:
• Student Attitudes Survey
• State Standardized Test Scores
• Qualitative Surveys of STEM Team Participants
Another valuable assessment measure is an open-ended
survey of the experiences of the STEM Team members,
including the practicing engineers and teachers. In
Appendix C3 you will find two qualitative surveys, one
for STEM team teachers and the other for all other
members of the STEM Team. These surveys will help
evaluate the experiences of the team members and allow
you to make adjustments to your program.
Make sure you get Institutional Review Board
Clearance and have parents fill out permission slips
before you implement the above evaluation measures.
Student Attitudes
Attitudes Sur
Survey
In Appendix C, you will find the attitudinal evaluation
instruments developed by Sumru Erkut and Fern Marx
from the Wellesley Centers for Women. The evaluation
focuses primarily on changes in students’ attitudes
(liking or disliking science, math, and engineering;
plans for studying these subjects; understanding the link
between these subjects and STEM careers; feelings
about STEM careers). The assessment instrument was
piloted several times in eighth grade classrooms and
showed high levels of reliability and validity. For
further information on the development of the
instrument and 4 Schools for WIE survey results visit
the website at www.stemteams.org.
The Student Attitude Evaluation consists of preand post-intervention surveys to measure change in
students’ attitudes over the course of the school year.
Ideally, the survey should be administered both in
classrooms working with the STEM Team and in
control classrooms where there is no STEM Team
intervention. The assessments should not be
administered by the classroom teacher but rather by an
outsider, such as a member of the STEM Team. For
information regarding administration of the survey see
Appendix C2. The parent permission letter, also found
in the appendix, should be signed before the first survey
is conducted.
Standardized Test Scores
Using standardized test scores is another method of
evaluating the effectiveness of your STEM Team
program. You can compare test scores in the areas of
technology and engineering for classes that did and did
not have the STEM Team intervention.
10
Chapter Four:
Four:
Developing Curriculum
Guidelines for Creating Gen
GenderderEquitable Engineering Ac
Activities
Units
Activity should
• provide opportunities for students to present
multiple solutions to the same problem;
• expose students to the wide range of
engineering fields;
• be delivered by a teacher or team member
who is enthusiastic, has gender equity
expectations, and works as a coach to
encourage and increase confidence;
• use gender neutral language;
• be hands-on;
• develop design process, critical thinking, and
communication skills;
• be done in small co-operative learning
groups (monitoring groups will help ensure
equal time for all students);
• emphasize relevance of activity to students’
everyday life and society;
• create equitable baseline by providing
necessary background information
and skills;
• be prepared in advance;
• include time for evaluation, reflection, and
redesign.
The 4 Schools for WIE collaboration has developed
nine curriculum units that may be used as a basis for
starting a STEM Team program. This section discusses
how your STEM Team can develop similar units.
As mentioned previously, ideas for initial units are
suggested at the original STEM Team training. These
ideas are further developed through research and team
meetings. The amount of time required to develop an
activity will depend on the complexity of the activity
and the size of the STEM Team. Handouts for the
activity should be developed, and the activity should be
piloted in the classroom. Activities can then be revised
based on classroom response.
Some main considerations in developing an activity
include the following:
• Is it gender-equitable? Does it meet the criteria
established by your team in the training session?
• Does it meet the national and state curriculum
frameworks for the grade level in which it is being
implemented?
• Does it fit into the science teacher’s curriculum?
The 4 Schools for WIE collaboration has established
guidelines for creating gender-equitable engineering
activities. As a basis for these guidelines, we used
Gardner, Mason, and Matyas' list of criteria for
equitable science activities and the research and
experience of several of the principal investigators on
the team.40 Your STEM Team may use these guidelines
as a basis for creating your own activity or you may
create additional guidelines based on your own
experience and research. You may also wish to use the
“Gender-Equitable Practices” worksheet found in
Appendix B8. You can use this either as a self assessment or as an introduction to small group
discussions on gender equity in the classroom.
Activity Development Process
Steps for the development of an engineering activity:
• Brainstorm ideas for project.
• Choose project idea.
• Fill out a team contract.
• Make sure that the project meets the engineering
frameworks.
• Make sure that the activity is gender-equitable.
• Create a manual and worksheets.
• Finish and publish the activity.
11
Brainstorm ideas for project. Ask teachers which
areas are not covered by technology teachers or the
current curriculum. The project may relate to a real
world resource your team has readily available to them.
For example, you could choose something related to the
products produced by the industry partner.
Make sure that the activity is gender-equitable.
Using the guidelines above, teams should be certain that
the activity meets the criteria for a gender-equitable
engineering activity. Activities should demonstrate the
helping nature of engineering.
Create a manual and worksheets. Using the suggested
format in Appendix E, write activity directions that can
be used by the STEM Team or by an individual teacher
when she presents the activity to students. This write-up
should contain procedures, worksheets, and assessment
tools.
Choose a project idea. Based on your brainstorming
activity, choose a project that will provide the most
value to the STEM Team in terms of equity and
engineering concepts.
Fill out a team contract. Using a contract helps
establish a timeline for completion of an activity and
assigns responsibility to various members of the team
for certain deliverables associated with the project, such
as a manual, worksheets, lesson plans, or supplies. A
sample contract can be found in Appendix D.
Finish and publish the activity. Completed activities
that have been piloted in middle school classrooms can
be uploaded to the STEM Team's website,
www.stemteams.org. Further information on the
development of a curriculum unit can be found at
www.stemteams.org.
Make sure that the project follows the engineering
frameworks.
Through training, your team should be familiar with the
national frameworks, as well as the frameworks in your
state. In addition, your school district may publish
specific curriculum goals. A successful activity will
address several technology and engineering
frameworks.
12
Chapter Five:
Curriculum Units
The 4 Schools for WIE STEM Teams have developed
nine curriculum units. These units have all been piloted
in middle school classrooms to make sure that they meet
the needs of eighth grade science teachers. All
necessary worksheets and instructions are supplied.
Below is a table listing the units and their engineering
disciplines.
Activity
Engineering
Discipline
All Engineering
Disciplines
Great Orange Juice Squeeze
Chemical Engineering
Solar Chocolate Factory
Environmental and
Electrical Engineering
Binary and Communication
Electrical and Computer
Engineering
Systems
Simple Circuits
Electrical and Computer
Engineering
Wacky Shoes
Mechanical Engineering
Bridges Connecting Our
Civil Engineering
World
Broken Bones
Biomedical Engineering
Making Bacteria Glow
Biomedical
13
Engineering design
Learning Strand:
Science and Engineering
Concepts:
All steps of the engineering design
process
Preparation Time:
60 minutes (after materials have
been collected)
Activity Time:
90 minutes (two-classroom periods)
Level of Difficulty: 2 (Scale of 1-5, with 5 as most difficult)
Group Size: 4 – 5 students per group (attention should be paid to make sure that groups
are gender-equitable)
Grade Level: 7 – 8
Cost: The cost of the activity is under $10 per class.
Purpose
The purpose of this activity is to introduce students to the concepts of the engineering
design process and engineering careers. Students will be introduced to the major
engineering disciplines as well as gain exposure to the engineering design process
through a hands-on activity.
Outcomes
By the end of this activity, students will be able to:
1. Identify all steps of the engineering design process;
2. Describe some engineering disciplines; and
3. Have some understanding of the connection between math, science, and
engineering.
14
Overview
Session 1:
Session 2:
Engineering in Our Daily Lives
Background for the Teacher
This activity is designed to provide an overview of the different engineering disciplines
and encourage students to start thinking about engineering. This activity will help
students make the connection between science and engineering.
Ideally, a team of female engineers should come into the classroom and present an
overview of the engineering profession and help lead the activities. Try contacting a
university in your area to ask for student volunteers. Many universities have
organizations for engineering students.
Materials
Per group
• 50 straws
• 5 feet of masking tape
• 2 – 3 tennis balls
Doing the Activity
Session 1
Explain to the students that you would like them to work as a team to design something.
Give each student a copy of the Straw Towers worksheet and help them work through the
activity.
Explain to students that they have just acted as engineers. Engineers work in teams and
use the engineering design process to solve problems.
Hand out the second worksheet. The engineering design process is very similar to the
scientific method used in your science classes. Engineers use their knowledge of math
and science to solve problems. For example, when building the straw tower the students
15
needed to use some math skills to determine how many straws it would take to reach the
required height. They also applied some physics principles to stop the tower from
toppling over. Using knowledge they already possessed, they were able to design a straw
tower.
Session 2
Ideally, a team of female engineers should come into the classroom and present an
overview of the engineering profession. They may want to use the Introduction to
Engineering presentation available at www.stemteams.org, or they can design their own
presentation.
Optional Homework Assignment:
Ask students to compare and contrast the scientific method and the engineering design
process and explain why they are important.
16
Worksheet 1
Straw Tower Activity
Challenge: You’re stranded on an island and are running out of food. You see a
ship passing and want to signal it. You decide to build a tower and attach a light
to the top. The ship is moving quickly, so you only have 15 minutes to build your
tower before the ship will be out of range. Your goal is to build the tallest tower
possible that will support the weight of the signal light.
Procedure:
1. Your teacher will put you in a group with 4 other students to solve this
challenge.
2. You will use a tennis ball to represent the signal light and straws and masking
tape to build the tower.
3. You will have 5 minutes to plan your design before the 15-minute time limit
begins.
17
Step 8:
Redesign
Step 5:
Construct a
Prototype
Step 6:
Test/Evaluate
Solution
18
Step 1:
Identify
the Problem
Solutions
Step 3:
Develop
Possible
Step 2:
Research
the
Problem
Step 4:
Select a
Solution
Engineering Design Process
Step 7:
Share
the Solution
Worksheet 2
Teacher’s Guide: Engineering in our Daily Lives
Teachers or engineers please read the following to the students and ask them to
make a note each time they hear an object or word they think was created by
engineers. Underlined words are all engineering related. There are 45 words
underlined
Do you know how engineering affects your life everyday? Engineering is part of
almost everything you do, from the moment you wake up until you go to bed at
night. Listen to the following and note any items you hear that you think might be
created by engineers:
Your alarm clock went off at 6:00 am this morning but you just didn’t want to move
yet, so you hit the snooze alarm several times. Finally you roll out of bed, turn on
the light, and head for the stereo to put on a little morning music.
After a nice long hot shower, you dry off with one of those great smelling towels just
washed in the best smelling fabric softener. You throw on your favorite shirt, pair
of jeans, and sneakers, do your make-up if necessary and quickly dry your hair with
that super fast hair dryer of yours. After using your electric toothbrush and
favorite toothpaste you are ready to head down to breakfast.
Ah, breakfast the most important meal of the day. Of course, you are running late
so you just grab a quick glass of orange juice and pop a bagel in the toaster. You
grab your backpack and make it to the corner just in time to catch the school bus
which narrowly misses getting in an accident because the traffic light at the busy
intersection near school isn’t working right. It’s a really bumpy ride; wouldn’t it be
great if someone would fix all those potholes in the road?
At school, you are looking forward to another great day; especially science class
with Mrs. ________________. You are going to be doing an experiment today using
chemicals and Bunsen burners. Sounds like fun. For history class you need to do
some research on the internet using the computers in the library.
After school you get to relax because Ms. ______________- didn’t give you any
homework tonight. You watch a little TV , spend sometime on the computer instant
messaging , get a couple of calls on your cell phone, and spend the time until dinner
listen to your favorite music on your MP3 player!
You are in charge of cooking dinner tonight so you check the freezer to see if there
are any frozen dinners you can heat up in the microwave. You’re in luck!!
After dinner, you spend some time playing video games with your little brother or
sister and then head up to bed. On your way upstairs you stub your toe and head to
the bathroom for a band aid. You grab some ibuprofen for the pain and head off to
bed.
19
By Katherine S. Ziemer, Tracy Carter, and Saloni Bhardwaj
With special thanks to Cheryl Hall, Hannah Goon,
Mark Knapp, Shannon Ingraham, and Paula Leventman
The Great Orange Squeeze
Overview
The Great Orange Squeeze module is designed to generate student interest in science,
math, and engineering by building a connection between engineering careers and helping
society. It also incorporates active learning, experience-oriented tasks, and inquiry-based
learning of the design process. The Great Orange Juice Squeeze module is the result of a
joint effort between Northeastern University, Raytheon Corporation, the Josiah Quincy
Upper School, and the Grover Cleveland Middle School. The goal of this joint venture is
to develop science and engineering activities that are gender-, culture-, and classequitable as well as interactive and fun. In addition, the female engineers from
Northeastern University and Raytheon Corporation support the teachers in class
activities, and their presence in the classroom provides engineering role models for
students.
Gender Equity
In order to ensure gender equity during execution of The Great Orange Squeeze, special
attention should be paid to the following points:
•
•
•
•
•
•
•
•
•
Teacher has equal expectations for all students.
Written materials and verbal instructions use gender-free language.
Relevance of activity to students' lives is stressed. Benefits to society are also
noted.
"Hands-on" experience is required for all students.
Small group work is used.
Activity develops science process skills.
Exercise does not demand one "right" answer.
Activities do not utilize materials and resources exclusively familiar to white,
male students.
Career information relevant to the activity is presented.
Science and Engineering Concepts
The Great Orange Squeeze addresses many science and engineering concepts and
illustrates both the differences and the interdependencies between science and
engineering. Specific topics described in the Massachusetts Science and Engineering
Frameworks are listed below.
20
Massachusetts Science and Engineering Frameworks Addressed in
“The Great Orange Squeeze”
1) Earth and Space Science: Heat Transfer in the Earth System
2) Life Science: Energy and Living Things
3) Physical Sciences
a) Properties of Matter
b) Elements, Compounds, and Mixtures
c) Heat Energy
4) Technology/Engineering
a) Materials, Tools, and Machines
b) Engineering Design
c) Communication Technologies
d) Manufacturing Technologies
e) Transportation Technologies
Module Description by Activities
This module is a series of six activities. This module is intended to be flexible and
adaptable so that some activities may be left out or expanded upon depending upon what
aspects of science and engineering the teacher wishes to emphasize. Prior to the first
activity, students should be exposed to a presentation describing engineering careers that
answers the questions, “What is an Engineer?” and “What does and Engineer Do?”
Example presentations are provided in the chapter Introduction to Engineering in this
manual and in the extensions section of Activity 1 of this chapter.
Activity 1, “Manufacturing and Transportation of Orange Juice,” presents a challenge
designed to generate student interest and require the use of both science and engineering
concepts to solve. The challenge is as follows:
In the United States, many school children do not receive proper
nutrition. Vitamin C is especially important for growing children.
This important vitamin is needed everyday for a strong immune
system, to resist infection, and to maintain the body’s ability to
heal itself. An 8-ounce glass of orange juice contains 100% of the
daily-required vitamin C.
As an engineer at Tropicana you are trying to sell your orange
juice to the Director of Food Services for the Boston Public
Schools breakfast program. However, due to recent budget cuts,
the director will not buy it unless it meets the budget constraint of
$0.25 per student.
How can you get nutritious, good-tasting orange juice from Florida
to Boston in an affordable way?
21
In this activity students are introduced to the engineering design process and they work
on the first three steps: identify the need or problem, research the problem, and develop
possible solutions. First, the students identify the problem from the challenge statement.
Then they research different transportation systems that will be able to deliver orange
juice to the final destination and determine the cost associated with each system to see if
any meet the budget constraint. The students also research the different types and costs of
commercial orange juice to see how these costs influences their decision. By the end of
the activity, students must conclude that due to budget constraints the solution is to
provide concentrated orange juice to the schools.
Activity 2, “Heat Transfer in the Production of Orange Juice,” is science-based. The
students investigate different forms of heat transfer and discover how they work. The
students use conduction, convection, and radiation to concentrate orange juice. By the
end of the activity, they must choose one method of heat transfer to manufacture their
concentrated orange juice.
Activity 3, “Flowsheets and Procedures: Engineers’ Communication Tools,” addresses
the “communication of solutions” step of the engineering design process. Every
manufacturing process, independent of the complexity of the process, must have a
flowsheet and a procedure. In this activity, the students must draw a flowsheet and write
a procedure for a simple process, producing a new snack product. This activity leads into
Activity 4, “Orange Concentration Prototype I.” Here the students design a prototype of
a process (Step 5 of the Engineering Design Process) to concentrate their orange juice by
choosing their best heat transfer method. They must also create a flowsheet and
procedure for their process. They will discover the need for more science to complete
their flowsheet, procedure, and prototype.
In Activity 5, “Orange Concentration Flowsheet and Prototype II,” students must
experimentally determine the amount of fresh juice to add to different concentrations of
orange juice to meet the taste quality requirement. Then they will finalize their flowsheets
and prototype with this new science information and determine the cost per 8-ounce glass
of juice produced.
Finally in Activity 6, “Orange Concentration Process: Test and Retest,” students must
demonstrate their process and evaluate their product’s ability to meet the challenge. Then
students will present their solution to the class incorporating their flowsheet and
procedure and recommending improvements to their process design.
22
Implementation
Educators should pick and choose activities that are relevant to their course objectives.
Many of the activities can be used independently of the others and with a variety of
implementation strategies. For each activity, one strategy is suggested, but alternatives
are mentioned in the text. The “Extensions” section of each activity provides
opportunities for more in-depth coverage of the topics and, in some cases, additional
related activities.
23
Part One: Manufacturing and Transportation of Orange Juice
Learning Strand:
Physical Science
Engineering Design
Manufacturing Technologies
Transportation Technologies
Concepts
Concentrate
Cost Analysis
Density
Evaporation
Homogeneous Mixture
Mass
Pasteurization
Transportation Systems
Volume
Preparation Time:
60 minutes
Activity Time:
90 minutes
Level of Difficulty:
1
(on a scale of 1 – 5, with 5 as most difficult)
Group Size:
4
Purpose
The purpose of part one of this activity is to introduce students to the “Great Orange
Squeeze” module and to motivate them to use both science and engineering concepts to
complete the challenge of the Great Orange Squeeze. In “Manufacturing and
Transportation of Orange Juice,” students will:
1) Understand the challenge of the Great Orange Squeeze in terms of the first
three steps of the engineering design process
2) Understand the background information necessary to approach the challenge’s
possible solutions
3) Discover the need for both science and engineering to solve the challenge
24
Outcomes
1)
2)
3)
4)
Identify the problem statement
Identify and describe cost-effective transportation systems
Discuss the role of cost and quality in an effective engineering solution
Understand the need to remove water from the orange juice in order to
develop possible solutions to the challenge
5) Understand the need to discover the science of heat transfer in order to
engineer a process to remove water from orange juice
Other skills practiced in this activity include brainstorming, analytical thinking, and
information gathering.
Overview and Connections
In this activity students are introduced to the challenge of delivering low cost, good
tasting orange juice from fresh oranges in Florida to Boston. (There are many locations
that can be chosen for the final destination; however, the location should be a place that
students can relate to.) The critical constraints that must be conveyed are that there is a
budget limit and fresh juice spoils in 48 hours.
When solving any engineering problem, engineers use the design process. There are eight
steps.
1.
2.
3.
4.
5.
6.
7.
8.
Identify the need or problem
Research the problem
Develop possible solutions
Select the best possible solution(s)
Construct a prototype
Test and evaluate
Communicate the solution(s)
Redesign
This module will engage the students in the first three steps of the design process. The
first step in the design process is to identify the need or problem. The students will read
the challenge and identify what they need to accomplish. The next step is to research the
problem, which means examining the current state of the issue and current solutions, as
well as exploring other options via the Internet, library, or interviews. The third step is to
develop possible solutions by brainstorming, using math and science, articulating
possible solutions in two and three dimensions, and refining these possible solutions.
25
Activity Synopsis
•
•
•
•
•
Introduce the challenge through a presentation and worksheets
Discuss modes of transportation and orange juice
Make unit conversions for cost analysis
Conduct a taste test of types of orange juice
Conclude with a discussion
Background
In this activity, students will be playing the role of engineers. Their challenge is to costeffectively deliver orange juice from Florida to its final destination. Engineers are
involved in every aspect of delivering a product to the consumer. Engineers design the
process to manufacture the product. They deliver a product that meets the demands of the
consumer, including cost and quality considerations. Environmental engineers design the
safety systems for the process to ensure a healthy work environment. Engineers design
the packages that the product is shipped in, and they design a system to deliver the
product to the consumer. Process engineers need a solid understanding of science to
design a process, and manufacturing and transportation engineers need to know the
design process to plan a distribution system.
Orange Juice
Orange juice is a homogeneous mixture. It is made up of natural sugars, acids, other
soluble solids, and water. The juice comes from the juice sacs in the orange. Only 50% of
the total weight of the orange is juice.
Orange juice can be purchased by the consumer in many different forms:
•
•
Fresh Orange Juice: The orange is squeezed and the juice packaged. The juice
comes in plastic containers or cardboard cartons and can be drunk immediately.
Chilled fresh orange juice will spoil after two days. This is the most expensive
form of orange juice and is priced by the seller. It can cost as much as $21.25 per
gallon (Consumer Prices 2003), although it is typically sold in single serving
sizes.
Pasteurized Orange Juice: Fresh orange juice is pasteurized to kill harmful
bacteria. This form is sold in cartons, bottles, and jugs clearly labeled "not from
concentrate.” This form of juice also comes ready to serve and when properly
chilled, it has a shelf life of between 45 days and two months. This is the next
most expensive form, costing approximately $6.25 per gallon (Consumer Prices
2003).
26
•
•
o Pasteurization:
The pasteurization process is named for the French scientist Louis
Pasteur. Pasteurization is used to partially sterilize liquids and
some solids to kill harmful bacteria such as E. coli and Salmonella.
This also increases the shelf life of the products since bacteria are
the cause of “spoilage.” Pasteurization is used in processing milk,
orange juice, wine, and beer, as well as cheese.
o Orange Juice and Pasteurization:
Oranges naturally have bacteria present. When the oranges are
squeezed, bacteria enter the juice. If bacteria aren’t removed, the
juice will mold and spoil. Fresh orange juice should be heated to
160° F (71.1° C) to ensure that harmful micro-organisms are
destroyed.
Reconstituted Orange Juice: This type of orange juice is concentrated and then
reconstituted. It is ready to serve and comes in plastic containers or cardboard
cartons. Properly chilled, it has a shelf life of 60 days, and it costs approximately
$3.60 per gallon (Consumer Prices 2003).
Frozen Concentrate of Orange Juice: Since orange juice is a heterogeneous
mixture, its components can be separated by their boiling points. Orange juice
concentrate is made by heating orange juice for an extended period to remove the
natural water. However, as the water evaporates, delicate compounds also
dissipate in the heat giving the juice a "cooked flavor." In order to combat the
“cooked flavor” after concentrating, engineers add a small amount of fresh juice
to the concentrate to enhance the flavor. While concentrating does affect the
flavor, by removing 75% of the water, the cost to the consumer decreases by 85%.
By removing water, the cost to ship the product to its final destination is reduced
and this cost reduction is passed on to the consumer. Frozen juice costs
approximately $3.40 per gallon (per gallon of reconstituted juice) (Consumer
Prices 2003).
After concentrating the orange juice, manufacturers then freeze the juice
concentrate. Freezing the concentrate extends the shelf life up to two years.
Frozen concentrate comes in plastic containers or cardboard and metal containers.
To serve, it must first be mixed with water to reconstitute the juice.
Quality
The quality of the orange juice can be measured in many ways including taste, shelf life,
and amount of vitamin C. Taste is a qualitative measure that students can explore through
a taste test of various types of commercially available juices, as described in this activity.
To improve the taste of concentrated orange juice, manufacturers add fresh orange juice
to the concentrate prior to freezing. The students can experiment with the impact of fresh
juice on the taste of concentrated juice in parts five and six of this activity.
27
Spoilage and shelf life are a function of the type of orange juice. Fresh orange juice will
spoil after 48 hours. Chilled, pasteurized juice has a shelf life of between 45 days and two
months. Chilled, reconstituted juice has a shelf life of approximately 60 days. Frozen
concentrate has a shelf life of up to two years. In determining an effective mode of
transportation, spoilage of the juice should be considered.
Vitamin C is often added to commercially available juice of many types. The
concentration process does break down the naturally occurring vitamin C in oranges. A
simple bench top test for vitamin C content is part of the Extensions for part five of the
activity.
Cost and Units of Measure
Engineers use many different units of measure, and often they need to convert from one
unit to another. Liquids are often described using volumes, but shipping companies give
prices in terms of mass. Engineers must be able to calculate the mass of a given volume.
This can be done either by measuring the mass of a given volume, or if the density of the
substance is known, the engineer can calculate it mathematically. Some useful units of
measure and some equivalents are listed below:
Volume:
Fluid ounces: 1 fl oz = 29.57 mL
Gallons: 1 gal = 3.7854 L
Liters: 1 L = 1,000 mL (milliliter)
Density:
The density of water is 1 g/mL.
Density can be determined by measuring the mass of a given volume.
Mass:
Ounce: 16 oz = 1 lb
Pound: 1 lb = 453.59 g
Kilogram: 1 kg = 1,000 g
Example Conversion Sheet:
1. Determine the weight of 8 fluid ounces in pounds.
•
Convert fluid ounces to millimeters [Note: 1 fl oz = 28.4 mL]
(8 fl oz)(28.4 mL/1 fl oz) = 227.27 mL of OJ
28
•
Convert volume to mass using density [Note: density of water = 1g/mL and the
density of fresh OJ is similar. However, you can determine the exact density of OJ
by measuring the mass of a given volume.]
(227.27 mL)(1g/1mL) = 227.27 g of OJ
•
Convert grams to pounds [Note: This is the mass of 8 fl oz of OJ.]
(227.27g)(1lb)
453.6g
= 0.50 lb
2. Determine the cost per 8-ounce glass of orange juice for each method of shipping.*
•
Shipping by PLANE = $3.00/lb
(0.50 lb)($3.00/lb) = $1.50 per 8 fl oz
•
Shipping by TRUCK = $0.78/lb
(0.50 lb)($0.78/lb) = $0.39 per 8 fl oz
•
Shipping by TRAIN = $0.72/lb
(0.50 lb)($0.72/lb) = $0.36 per 8 fl oz
•
Shipping by BOAT = $0.66/lb
(0.50 lb)($0.66/lb) = $0.33 per 8 fl oz
*Note that none of these shipping methods meet the $0.25/8 fl oz serving budget
constraint! So, transporting fresh orange juice will not meet the challenge.
Transportation
There will be some sort of transportation system involved in supplying the orange juice to
the final destination. Not all modes of transportation are applicable to all destinations (no
ship transportation to Kansas, for example).
The cost to ship by plane is $2.80/lb, by ship is $0.55/lb, by train is $0.60/lb, and by
truck is $0.66/lb. (Prices quoted are for bulk commercial next day air and ground delivery
from Florida to Boston by UPS.com. Prices effective in summer 2003.) Note relationship
of cost to weight. Therefore, the more an item weighs, the more it costs to ship it.
29
Materials
Per Student
• Activity worksheets
• 3 cups (optional taste test)
• Samples of different varieties of orange juice for tasting (optional)
Per Group of 4 Students or More
• 1 balance (maximum weight 1 kg)
• 1 250 mL graduated cylinder
Preparation for Activity
1. Schedule the activity. This activity will take 90 minutes and can be divided into
two class periods, with the first class period devoted to introducing the challenge,
discussing transportation issues, and determining cost data. Then, for homework,
students can look at home or in a local grocery store for orange juice products.
The second period will cover the students’ knowledge of orange juice products.
They can brainstorm how to solve the challenge of decreasing the cost while
maintaining the quality of the orange juice.
2. Provide students with different types of orange juice to taste. Types include
fresh (hand-squeezed or purchased from store), pasteurized, reconstituted, and
concentrated.
3. Assign students to search the web for information on orange juice, or print
relevant information from the following websites:
www.tropicana.com/biz/about/process.htm
www.ultimatecitrus.com/pdf/fcoj.pdf
www.minutemaid.com
4. Consider health concerns. Students will be drinking the juice, so the cups need
to be clean. The juice also needs to be refrigerated.
5. Update and copy the activity sheets. Choose a location for the challenge that the
students can identify with. Check the prices of orange juice at the local grocery
store. Check the UPS.com website for shipping prices reflective of the
destination.
6. Assign the students to groups. Students should work in groups of at least four
students.
7. Review gender equitability activity checklist. (See Reference Section.)
30
Doing the Activity
NOTE: there are many ways to implement this activity. The steps below and the
worksheets and presentations are guides. You may wish to lengthen or shorten the
activity to meet your needs.
2. Introduce the challenge. A PowerPoint presentation is provided on
www.stemteams.org to help present this activity to the students. First students are
reminded that engineers work with almost everything we eat, drink, wear, touch,
see, and hear in our daily lives.
2. Distribute the challenge worksheet. Next the challenge is stated to the class.
In the United States, many school children do not receive proper nutrition.
Vitamin C is especially important for growing children. This important
vitamin is needed every day for a strong immune system, to resist
infection, and to maintain the body’s ability to heal itself. An 8-ounce
glass of orange juice contains 100% of the daily-required vitamin C.
As an engineer at Tropicana you are trying to sell your orange juice to the
Director of Food Services for Boston Public Schools breakfast program.
However, due to recent budget cuts, the director will not buy it unless it
meets the budget constraint of $0.25 per student.
How can we get nutritious, good-tasting orange juice from Florida to the
breakfast programs in Boston (or your destination) in an affordable way?
Extension topics that can be discussed at this point are the nutritious benefits of
orange juice versus other juices.
3. Discuss the engineering design process. When engineers are faced with a
problem, they use the engineering design process as a systematic approach to
solving the problem. The steps of the design process are:
1)
2)
3)
4)
5)
6)
7)
8)
Test and evaluate
Redesign
31
4. Identify the need and problem. In this case the need is to provide kindergarten
students with a nutritious breakfast. And the problem is how to get orange juice
from Florida to Boston that only costs $0.25 per student.
5. Group work on researching the problem. Split the class into groups and ask
them to work on Worksheets 1 and 2.
6. Class discussion on Researching the Problem. In this example we ask how do
we physically get orange juice from Florida to Boston (or your destination). The
main modes for mass transportation of industrial products are planes, trains,
trucks, and ships. Fresh orange juice can be sent to Boston by many different
modes of transportation, and in this case all modes of transportation (plane, ship,
train, and truck) are possible.
As an engineer, when considering which mode of transportation to use there are
three variables that need to be considered:
a. The amount of time it takes to transport orange juice from initial to final
destination
b. The cost to transport orange juice from initial to final destination
c. The taste of the juice and whether or not it has spoiled by the time it
reaches the final destination
While fresh orange juice can be sent to Boston by many different modes of
transportation, the delivery time is affected by the choice. It takes a matter of
hours by plane but days to weeks by ground and water.
The cost to ship by plane is $3/lb, by ship $0.66/lb, by train $0.72/lb, and by
truck $0.78/lb. Note the relationship of cost to weight. Therefore, the more an
item weighs, the more it costs to ship it.
The taste of orange juice is affected by how it is handled. All modes of
transportation must be outfitted with a cooling system to keep the juice cold.
However, even when chilled, fresh orange juice will spoil after only 48 hours.
This makes it difficult, if not impossible, to produce fresh orange juice in Florida
and distribute it outside the area. Although a plane can move it in a matter of
hours, the juice still has to be put on the shelves and the consumers have to be
present to purchase it. Students might suggest shipping the oranges to the final
destination and then producing the juice locally. That is how we can have fresh
juice locally. However, it is not cost effective to transport oranges, since only
50% of the total weight is juice.
7. Calculate the cost to ship. Using the given information, the cost to ship an 8
ounce serving of fresh juice can be calculated to see if it meets the budget
constraint. Since the cost is indicated in $/lb, some unit conversion is required.
Worksheet 3 and the Conversion Sheet guide students through the unit
32
conversions. Alternatively, an Excel spreadsheet can be used (see Extensions). If
students are not familiar with unit conversions, some background may be
necessary.
In order to calculate the shipping cost, volume (8 ounces) must be converted to
mass (lb). In order to do this, the density of orange juice must be used. The
density of fresh juice can be approximated as the density of water (1 g/mL) for the
sake of simplicity, or the actual density can be determined by finding the mass of
a specific volume of the juice. You can ask students to do this in their groups. The
students should use the 250 mL graduated cylinder and the balance to measure the
mass of 235 mL (~8 ounces) of fresh orange juice. Divide the mass by the volume
to determine the density.
Once the volume is converted to mass, the mass is then multiplied by the shipping
cost to determine the cost for shipping an 8 ounce serving. In this example the
cost limit is $0.25/serving. If the cost is greater than $0.25/serving, another
calculation can be made to determine how many ounces can be shipped for $0.25.
If you multiply $0.25 by the inverse of the cost, you can determine the weight,
and then by using the density you can determine the volume. By doing this
exercise, it can be estimated how much water needs to be removed from the juice
to ship it to meet the budget constraint. It is an estimate because the density of the
juice changes as the water is removed since this is a mixture and NOT a pure
substance.
8. Assign Worksheet 4 and the OJ Survey for homework. Ask students to look at
home and in the grocery store to find the different varieties of orange juice. Ask
them to search the web or their reading to find the differences between fresh,
pasteurized, reconstituted, and frozen concentrated orange juice.
9. Serve the class different forms of orange juice. Ask the students to split into
groups and write comments on the cost and quality of different types of orange
juice.
10. Class discussion on buying orange juice (Worksheet 4 and OJ Survey).
Orange juice can be purchased by the consumer in many different forms:
•
•
Fresh orange juice: The orange is squeezed then packaged; to serve just pour
and drink. It comes in plastic containers or cardboard cartons. Chilled fresh
orange juice will spoil after two days. This is the most expensive form of
orange juice.
Pasteurized orange juice: Fresh orange juice is pasteurized to kill harmful
bacteria. This form is sold in cartons, bottles and jugs clearly labeled "not
from concentrate”; this also comes ready to serve. When properly chilled, it
has a shelf life of between 45 days and two months. This is the next most
expensive form, costing approximately $6.25/gallon (Consumer Prices 2003).
33
•
•
•
Reconstituted orange juice: This is orange juice that has been concentrated
and then reconstituted with added water. It is ready to serve and comes in
plastic containers or cardboard cartons. Properly chilled it has a shelf life of
two months, and it costs approximately $3.60 (Consumer Prices 2003).
Frozen concentrate of orange juice: Orange juice concentrate is made by
heating orange juice for an extended period to remove the natural water. After
concentrating the orange juice, manufacturers then freeze the juice
concentrate. Freezing the concentrate extends the shelf life up to two years.
Frozen concentrate comes in plastic containers or cardboard and metal
containers. To serve it must first be mixed with water to reconstitute the juice.
Frozen juice costs approximately $3.40/gallon of reconstituted juice
(Consumer Prices 2003).
Tang: Tang may also be suggested as a form of orange juice, but this is an
artificial orange drink. The list of ingredients is supplied in the Extensions
section at the end of this activity.
11. Group work on developing possible solutions. Divide the class into their groups
and have them work on Worksheet 5.
12. Class discussion on developing possible solutions. The students will find that no
mode of transportation will meet the budget constraint, so they must try to use
their scientific knowledge to suggest a solution to this problem. Since cost is
directly related to weight, scientists and engineers must work together to reduce
the weight by removing water. Thus the only economical solution is to
concentrate the juice by removing the water. How? We explore the science of heat
transfer in Activity 2 to discover how juice is concentrated.
Discuss the group’s findings on the quality of different types of orange juice.
Answers will vary.
The economic benefits of concentrating the juice must be balanced with a quality
decision since concentrating affects the taste. Therefore, engineers must test to
determine how much water to remove and how much fresh juice needs to be
added to enhance the taste. The unit conversion sheet used to determine the cost
of transportation will be expanded to include these and other factors as the
students move to Activities 5 and 6.
13. Clean up. Refrigerate remaining orange juice. Throw away juice cups. Collect the
worksheets for review.
34
STUDENT WORKSHEET
The Challenge: The Great Orange Squeeze!
In the United States, many school children do not receive proper nutrition.
Vitamin C is especially important for growing children. This important
vitamin is needed every day for a strong immune system, to resist infection,
and to maintain the body’s ability to heal itself. An 8-ounce glass of orange
juice contains 100% of the daily-required vitamin C.
As an engineer at Tropicana you are trying to sell your orange juice to the
Director of Food Services for the Boston Public Schools breakfast program.
However, due to recent budget cuts, the director will not buy it unless it
meets the budget constraint of $0.25 per student.
How can we get nutritious, good-tasting orange juice from Florida to the
breakfast programs in Boston in an affordable way?
35
STUDENT WORKSHEET
Name _________________________
Activity #1: Worksheet 1 - Transportation
Date ___________________
Fill in the chart below to answer the following questions:
1. Name possible means of transportation for moving the orange juice from Florida to
Massachusetts.
2. Identify variables that must be considered when choosing a mode of transportation.
3. What are the advantages and disadvantages associated with each type of
transportation?
Type of Transportation
Advantages
36
Disadvantages
STUDENT WORKSHEET
Name _________________________
Activity #1: Worksheet 2 - Transportation
Date ___________________
1. Complete the following chart indicating how the type of transportation selected could
affect time taste and cost.
Transportation
Time
Taste
37
Cost
STUDENT WORKSHEET
Activity #1: Worksheet 3 – Cost to Ship
Name _______________________________
Date _____________
The Orange Juice Challenge
RESEARCH THE PROBLEM: FORMS OF TRANSPORTATION
HOW LONG DOES IT TAKE?
~1500 miles)
Distance from Boston to Florida (e.g. Miami
Approximate Travel Time
Plane: 3.5 hours (expedia.com)
Truck: 26 hours (mapquest.com)
Train : 36 hours (amtrak.com)
freight ships are slow, 20 knots/hr (23
Ship: 65 hours
miles/hr)
HOW MUCH DOES IT COST?
Use the prices below to determine the cost of transportation for an 8
ounce serving of orange juice. Show your work.
8 oz. = _______ lb.
(1 lb = _________oz.)
plane ($3.00/lb)
train ($0.72/lb)
truck ($0.78/lb)
boat ($0.66/lb)
Rating the Forms of Transportation
A) Write the forms of transportation under “Travel time” in order from
best to worst. Repeat for “cost”.
Rating
Travel
time
Cost
Best(4)
(3)
(2)
Worst(1)
B) Total the points earned for each form of transportation.
boat
train
truck
plane
________
________
________
________
Conclusion:
38
STUDENT WORKSHEET
Conversion Sheet
1) Determine the weight of 8 fluid ounces in pounds.
• Convert fluid ounces to millimeters [Note: 1 fl oz = 28.4 mL]
(8 fl oz)(28.4 mL/1 fl oz) = 227.27 mL of orange juice
• Convert volume to mass using density [Note: the density of water is
1g/mL and the density of fresh orange juice is similar. However, you
can determine the exact density of orange juice by measuring the mass
of a given volume.]
(227.27 mL)(1 g/1 mL) = 227.27 g of orange juice
• Convert grams to pounds [Note: This is the mass of 8 fluid ounces of
orange juice.]
(227.27 g)(1 lb)
453.6 g
= 0.50 lb
2) Determine the cost per 8 ounce glass for each method of shipping.*
• Shipping by PLANE = $3.00/lb
(0.50 lb)($3.00/lb) = $1.50 per 8 fl oz
• Shipping by TRUCK = $0.78/lb
(0.50 lb)($0.78/lb) = $0.39 per 8 fl oz
• Shipping by TRAIN = $0.72/lb
(0.50 lb)($0.72/lb) = $0.36 per 8 fl oz
• Shipping by BOAT = $0.66/lb
(0.50 lb)($0.66/lb) = $0.33 per 8 fl oz
*Note that none of these shipping methods meet our $0.15/8 fl oz serving budget
constraint!
39
STUDENT WORKSHEET
Name _________________________
Activity #1: Worksheet 4 - Buying Orange Juice
Date ___________________
Use your experience to answer the following questions.
1. List the varieties of orange juice that you find in the store.
________________________________________________________________________
________________________________________________________________________
2. Compare the difference between the following types of juice.
a. fresh orange juice
__________________________________________________________________
__________________________________________________________________
b. reconstituted orange juice
__________________________________________________________________
__________________________________________________________________
c. frozen concentrate
__________________________________________________________________
__________________________________________________________________
40
STUDENT WORKSHEET
Name __________________________
Date __________________
OJ Survey
Directions: Answer the questions below based on your own or your
family’s consumer habits. Then, work together with your “Super 8”
group and collect data for your orange juice survey.
A) You, Your Family, and OJ
1. How often do you drink orange juice? (per year)
_______________________________________________________________
2. Why do you drink orange juice?
_______________________________________________________________
3. How much orange juice does your family drink in a year?
_______________________________________________________________
4. Who purchases the groceries in your family? ___________________Why does
he/she buy orange juice?
__________________________________________________________________
5. What do you think are the ingredients in orange juice?
__________________________________________________________________
________________________________________________________________
6. How much do you think a half gallon of Tropicana costs?
_______________________________________________________________
41
7. Do you think you get the U.S. recommended daily allowance of vitamin C
everyday? ________ Why?
__________________________________________________________________
________________________________________________________________
8. What are some foods that are high in vitamin C?
______________________________________________________________
______________________________________________________________
B) Now, in your “Super 8” group compile the data into one table (to be handed in) based
on answers for questions 1 and 2.
BONUS HOMEWORK
“Where’s the Vitamin C?”
A) Examine the nutrition label of ten different types of foods or beverages. (Choose a
variety.) Record the percentage of the U.S. recommended daily allowance for vitamin C
that one serving of that item provides.
B) Write a conclusion based on your collected data.
42
STUDENT WORKSHEET
Name _________________________
Activity #1: Worksheet 5 - OJ Comparison
Date ___________________
1. Name at least two ways that can you decrease the cost of orange juice yet maintain
the quality.
2. Explain how the cost and quality of fresh orange juice compares with that of frozen
orange juice.
43
Conclusions
By the end of this activity, the students should:
1) Be able to identify the problem. (How do you get orange juice from
Florida to Boston that costs $0.25 per student?)
2) Identify the main mode of transportation such as planes, trains, trucks and
ships. They should also determine that although planes are the fastest
mode of transportation, they are the least cost effective. However, the
most cost effective mode of transportation, by ship, is not fast enough to
ensure a fresh product.
3) Realize that fresh juice is the most expensive, but quality juice can be
produced more cheaply as frozen concentrate.
4) Determine that the cost associated with shipping orange juice is directly
proportional to the weight of the product distributed. In order to decrease
the cost, weight must be removed from the product. Therefore, water must
be removed from the juice.
5) Suggest ways to physically remove water from the juice such as by
heating.
Vocabulary
Concentrate: A mixture that has a lot of solute dissolved in it.
Density: The measurement of how much mass of a substance is contained in a given
volume.
Evaporation: The process that occurs when vaporization takes place only on the surface
of a liquid.
Homogeneous mixture: Two or more substances that are mixed together but not
chemically combined.
Mass: A measure of how much matter is in an object.
Pasteurization: A process that raises the temperature of liquids and some solids to
partially sterilize them and kill harmful bacteria such as E. coli and Salmonella.
Volume: The amount of space that matter occupies.
References
http://www.minutemaid.com
http://www.tropicana.com/index.asp?ID=60
http://www.ultimatecitrus.com/pdf/fcoj.pdf
44
Criteria for Equitable Science Activities
•
•
•
•
•
•
•
•
•
•
Teacher is enthusiastic and has equal expectations for all students.
Written materials and verbal instructions use gender-free language.
Relevance of activity to students' lives is stressed.
"Hands-on" experience is required for all students.
Small group work is used.
Activity develops science process skills.
Exercise does not demand one "right" answer.
Activities do not use materials or resources exclusively familiar to white, male
students.
Career information relevant to the activity is presented.
Examples of female and minority role models are included in the follow-up.
For more information see the following website:
Equity, Excellence & 'Just Plain Good Teaching'
www.enc.org/topics/equity/articles/document.shtm?input=ACQ-111551-1551
Extensions
Nutrition:
Orange juice contains several vitamins and minerals that are important for maintaining
good health. Among these are:
Vitamin C:
Daily consumption of vitamin C is important for developing a strong
immune system, resisting infection, and maintaining the body’s ability to
heal itself. An 8-ounce glass of orange juice typically contains at least
100% of the U.S. recommended daily allowance of vitamin C, whereas a
glass of apple juice may contain only 20%
Potassium:
This mineral is important for maintaining proper blood pressure, keeping
the nervous system vital, and regulating the fluid balance in the body.
Orange juice contains approximately 10% of the U.S. recommended daily
allowance of potassium.
Folate:
Folate is a B-vitamin. It is required for normal maintenance and growth of
cells. It can help reduce the risk of certain cancers, heart disease, and
stroke. It also reduces the risk of birth defects. Orange juice contains
approximately 15% of the U.S. recommended daily allowance of folate.
45
Artificial Orange Juice:
Tang is an artificial orange drink. It costs $2.50/gallon, and it is made with the following
ingredients:
Sugar, fructose, citric acid (provides tartness), calcium phosphate (prevents caking),
potassium citrate (controls acidity), ascorbic acid (vitamin C), orange juice solids, natural
flavor, titanium dioxide (for color), xanthan and cellulose Gums (provide body), yellow
5, yellow 6, niacinamide, artificial flavor, vitamin A palmitate, vitamin B6, riboflavin
(vitamin B2), BHA (preserves freshness), and folic acid.
Excel:
Introduce Excel for formulas in unit conversions. Graphing can also be introduced in
preparation for Activity 2.
46
In
Part Two: Heat Transfer in the Production of Orange Juice
Learning Strand:
Physical Science
Engineering Design
Concepts:
Conduction
Evaporation
Heat Transfer
Temperature
Preparation Time:
45 minutes
Activity Time:
90 to 120 minutes
Convection
Heat
Radiation
3
(on a scale of 1 to 5, with 5 as most difficult)
Group Size:
4
Purpose
The purpose of this activity is for students to discover the science of heat transfer in
order to solve the challenge of the great orange squeeze. In “Heat Transfer and the
Production of Orange Juice,” the students will:
1) Experiment with heat transfer using conduction, convection, and radiation
2) Understand the process of evaporation
3) Discover the rate of heat transfer under different heating conditions
Outcomes
At the end of this activity the students will be able to:
1. Identify the different types of heat transfer
2. Understand the impact of evaporation on the concentration and density of the
mixture
3. Evaluate the efficiency of each type of heat transfer in concentrating the orange
juice
Other skills practiced in this activity include brainstorming, analytical thinking, and
gathering information.
47
CONNECTIONS TO “THE GREAT ORANGE SQUEEZE”: At this point, the
students understand the shipping weight-to-cost relationship and have decided that
concentrating the orange juice is the best way to provide low-cost, good-tasting orange
juice to kindergarten breakfast programs in Boston. Now they will play the role of
scientist to discover the characteristics of the three forms of heat transfer (conduction,
convection, and radiation) and will observe their affect on the heating of orange juice.
This is part of researching the problem (Step 2 of the engineering design process).
This activity leads into Activity 3 where students will learn how engineers communicate
their findings through the use of processes, flowsheets, and procedures.
.
The eight steps in the engineering design process:
1.
2.
3.
4.
5.
6.
7.
8.
Test and evaluate
Redesign
CONNECTIONS TO THE ENGINEERING DESIGN PROCESS: Design step two
(research the problem) is illustrated and practiced in this activity. Students must develop
possible solutions for concentrating their orange juice and choose the best one based on
what they have observed.
OVERVIEW OF THIS ACTIVITY: In “Heat Transfer in the Production of Orange
Juice,” students will engineer possible solutions to how they will concentrate orange juice
using the tools available to them. In this activity, students will experiment with heat
transfer to understand the natural phenomena of heat, temperature, and evaporation and
then they will use this understanding to solve an engineering problem of how to
effectively concentrate fresh orange juice in order to supply economical and good quality
juice to distant locations.
48
Background
Evaporation is one industrial method used to separate a liquid mixture such as orange
juice. This type of separation makes use of the fact that the components of the mixture
have different boiling points. The boiling point is the temperature at which a liquid
becomes a gas. Since orange juice is made of water and soluble solids, the water can be
removed by boiling the juice. (The boiling point of water is 100°C or 212°F.) The
negative side to this method of separation is that some of the soluble solids are heat
sensitive and degrade. This has the effect of changing the flavor of the juice. In order to
combat the loss of flavor, small amounts of fresh juice are added to the concentrate.
Engineers and scientists work together to determine how much fresh juice needs to be
added to the concentrate for maximum consumer appeal.
When an engineer designs an evaporation process, there are many variables that must be
monitored. Two critical variables are temperature and volume. The engineer must know
how hot the evaporator is and how much liquid is in it. These variables can be measured
experimentally. The engineer is also interested in the rate of evaporation or the volume of
liquid vaporized in a certain amount of time. This can be calculated by measuring the
remaining volume with time.
Heat Transfer
An engineer also has to choose a method by which to heat the liquid. This involves
choosing a method of heat transfer. Heat is the movement of thermal energy from a
higher temperature to a lower temperature. Thermal energy is the total energy of all
particles, whereas temperature is the average energy (kinetic) of all particles. Heat is
typically measured in joules or Btu’s, and temperature in Fahrenheit or Celsius. There are
three methods of heat transfer: conduction, convection, and radiation.
Conduction
Heat is transferred by conduction without the movement of matter. Some examples
of conduction are:
•
•
•
•
A cup on a hot plate: Heat is transferred by conduction between the hotplate
(hot) and the cup (cold) and then between the cup (hot) and the liquid (cold).
A hot pack: Heat is transferred from pack (hot) to hands (cold); the result is that
your hands feel warm.
Rubbing hands together: Friction (hot) generates heat that transfers to hands
(cold); hands get warm.
Holding ice in hand: Heat transfers by conduction from hands (hot) to the ice
(cold); hands get cold and ice melts.
49
•
•
Breathing on window: Heat transfers by conduction from breath (hot) to the
window (cold); the moisture in the breath condenses on the cold window.
Ice in a drink: Heat transfers by conduction from the warm beverage (hot) to the
ice (cold), which cools the beverage.
Convection
Heat is transferred by convection by the movement of particles within a fluid. Some
examples of convection are:
•
•
•
•
•
•
A hair drier is forced convection. A fan moves the hot air molecules over cold wet
hair.
A hand drier is the same as a hair dryer. Hot air is blown over cold wet hands.
In breathing on hands, warm breath is moved over cold hands.
A fan mixes hot and cold air.
Hot food is cooled by blowing cold air over it.
Hot chocolate is cooled by stirring.
Radiation
In radiation, heat is transferred by electromagnetic waves. Radiation does not require
the presence of matter to transfer thermal energy. Some examples of radiation are:
•
•
•
•
•
Light bulb (hot) warms surrounding air (cold).
Heat lamp (hot) warms food (cold).
Radiator (hot) warms surrounding air (cold).
Hot potato (hot) warms surrounding air (cold).
Sun (hot) warms the earth (cold).
When choosing a method of heat transfer, engineers look at the rate of heat transfer. They
measure the increase of temperature with time. They balance that data with the cost of
heating to choose the best method for the process.
50
Materials
Per class
•
•
paper towels
refrigerator
Per group of 4 students or more
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
hair dryer
heat lamp
hot plate
stainless steel pot
2 glass cups
measuring cup
1 liter of orange juice
3 stopwatches
3 thermometers
ruler
3 metal spoons
1 pair of safety glasses/person
oven mitt
balance
1 250 mL graduated cylinder
funnel
2 ring stands
CAUTION:
Before running the activity, make sure that there is enough power to supply all the
heating elements for the entire class. Seek building supervisor to determine the limits of
the circuits in the classroom. The current draw is 2 amps for a 250 W, 120V GE Infrared
heat lamp, 10 amps for a 1200 W, 120 V Toastmaster single burner hot plate (model #
6431), and 15 amps for a 1875 W, 125 V Revlon hair dryer. If you cannot find this
information, the activity should be conducted by assigning one heating unit per group.
The students can also do this as an assignment. See the Extensions section.
1. Identify the workstations to make sure that students have enough space to do the
activity.
2. All cooking materials must be clean so that the students can consume the product.
If possible, materials should be strictly dedicated to the orange juice kit.
51
3. This activity can be run in either a lab or a classroom. The materials should be
distributed to activity stations in advance to save classroom time.
4. The worksheets should be printed for each student. Students should be broken
into groups of at least 4.
Doing the Activity
NOTE: It is assumed that students have had exposure to heat transfer and temperature
prior to this activity. If not, an additional lecture may be needed.
Student groups are given three containers of orange juice (volume = 200 mL),
thermometers, timers, a hot plate, a hair dryer, and a heat lamp. Each member of the
group should be assigned a task. One student should stir the solutions, one should
monitor the time, one should observe the temperature, and one should record the results.
Students measure the temperature increase with time for heating the orange juice by
conduction (hot plate), convection (hair dryer), and by radiation (heat lamp). Students
also observe water evaporation (steam rising from the surface of the heated liquid) and
measure the volume of the orange juice before and after heating. Suggested worksheets
are provided to aid in data collection.
Ideally, the heating portion of this activity should run for 40 minutes to allow time for a
reduction in volume by all methods of heat transfer. If this is not possible, it can be run in
20 minutes, which is enough time to allow substantial volume change by conduction, but
not so much by either convection or radiation. See the Extensions section for further
details.
Although the description of the activity below involves all groups using all three of the
heat transfer methods, the activity has been successfully implemented where each group
observes conduction and either convection or radiation. The students then share their data
so that all groups analyze the results of all three heat transfer methods.
1. Obtain all materials. Supply all materials and worksheets to the lab stations for
the students prior to the start of class.
2. Put on safety glasses. Since the students will be working with boiling liquids, it
is important to stress safety. This includes using safety goggles to prevent
splashing of hot liquids in the eyes and using oven mitts to handle hot surfaces.
3. Label one glass cup “hairdryer,” the second glass cup “heat lamp,” and the
stainless steel pot “hotplate.”
4. Measure the mass of each glass cup and the stainless steel pot and record the
results.
5. Pour 200 mL of orange juice into the glass cup labeled “hair dryer.”
52
6. Measure and record the mass of the juice.
The students will need to subtract the weight of the container from the combined
weight of the container and the juice to determine the weight of the juice.
7. Pour 200 mL of orange juice into the other glass cup labeled “heat lamp.”
9. Pour 200 mL of orange juice into the stainless steel pot.
The glass cups MUST NOT be placed on the hotplate because they will crack.
Before placing cups on or under heating equipment make sure they are turned off.
11. Place the stainless steel pot in the center of the hot plate.
12. Place the hairdryer 30 cm above the glass cup.
The hair dryer must be placed at least 30 cm above the cup or else the juice will
be blown out of the container.
13. Place the other glass cup 20 cm under the heat lamp.
Use clamps to secure the heat lamp in place.
14. Concentrate the orange juice.
After checking to see that students are working safely, allow them to plug in the
hot plate, hair dryer, and heat lamp.
15. Turn on the hot plate on high (setting 6).
16. Turn on the hair dryer on high.
17. Turn on the heat lamp.
18. Start the stopwatch; it should be counting up from 0 minutes.
The students will be recording the time at which the temperature is taken. This
will NOT be at regular intervals, but should not be more than 3 minutes apart.
19. Stir all orange juice containers continuously to make sure the temperature is
uniform.
It is important that the students stir the contents with a metal spoon and not with a
thermometer, especially if the thermometers are glass, since this would be a safety
hazard. The students should also use an oven mitt to handle the spoon since it will
get warm over time.
20. Measure the temperature of each container of orange juice and record your
results on the data sheets.
In order to take an accurate measurement, the bulb of the thermometer must be
completely submerged in the orange juice. Keep the thermometer submerged until
the temperature is stable.
21. Record any observations you may make during the course of your experiment.
This may include but not be limited to steam rising from the liquid, color changes,
and consistency changes in the liquid.
22. After 40 minutes, turn off all heating equipment.
In order to see a significant decrease in the volume of liquid on the hotplate, 40
minutes is necessary.
23. Measure and record the final mass of the orange juice heated by the hot plate.
24. Measure the final volume of the orange juice heated by the hot plate by pouring
the orange juice into a graduated cylinder and recording the results.
The students must use a graduated cylinder to measure the final volume so that
the measurement is precise.
53
25. Reconstitute the orange juice.
While the orange juice is in the graduated cylinder, add enough water to make the
volume 200 mL.
26. Pour the orange juice into a cup and label it with your name and method of
heating.
27. Place the orange juice in the refrigerator overnight. (Or cool by placing in an ice
bath for 5 minutes.)
28. Taste orange juice and rate on a scale of 1 – 5, where 1 tastes the best and 5 tastes
the worst.
29. Measure and record the final mass of the orange juice heated by the hair dryer.
30. Measure the final volume of the orange juice heated by the hair dryer by pouring
While the orange juice is in the measuring cup, add enough water to make the
volume 200 mL.
heating.
the worst.
35. Measure and record the final mass of the orange juice heated by the heat lamp.
36. Measure the final volume of the orange juice heated by the heat lamp by pouring
While the orange juice is in the measuring cup, add enough water to make the
volume 200 mL.
heating.
the worst.
41. Calculate the mass of the juice and the starting and ending densities.
The masses are calculated by subtracting the weight of the cup from the mass of
the cup plus the juice. The densities are calculated by dividing the starting mass
by the starting volume, and by dividing the ending mass by the ending volume for
each method of heat transfer.
After the activity is complete and the students have filled out the data sheets, discuss the
following:
• Which type of heat transfer is at work for:
o Hot plate-conduction, hair dryer-convection, and heat lampradiation
54
•
Heat
Transfer
Method
Conduction
Convection
Radiation
Compare and contrast each method:
Maximum
Temperature
(°C)
~100°C
< 100°C
<100°C
Rate (Fast,
Medium,
Slow)
Fast
Medium
Slow
Observation
During
Heating
Evaporation
Taste (Good, Observation
Better, Best) After
Heating
The students should be able to decide which method they would choose to heat their juice
in the condenser. This is based on the rate of heat transfer, meaning which method
removed water the fastest.
55
Procedure
Heat Transfer Using Conduction, Convection, and Radiation
Materials:
• hair dryer
• hot plate
• 2 glass cups
• 1 liter of orange juice
• 3 thermometers
• 3 metal spoons
• 1 oven mitt
• 250 mL graduated cylinder
• 2 ring stands
• heat lamp
• stainless steel pot
• measuring cup
• 3 stopwatches
• ruler
• pair of safety glass/person
• balance
• funnel
Procedure:
1. Obtain all materials.
2. Put on safety glasses.
3. Label one glass cup “hairdryer,” the second glass cup “heat lamp,” and the stainless
steel pot “hotplate.”
4. Measure the mass of each glass cup and the stainless steel pot and record the results.
5. Measure 200 mL of orange juice into the glass cup labeled “hair dryer.”
7. Measure 200 mL of orange juice into the other glass cup labeled “heat lamp.”
9. Measure 200 mL of orange juice into the stainless steel pot.
Before placing cups on or under heating equipment, make sure they are turned off.
56
11. Place the stainless steel pot in the center of the hot plate.
12. Place the hairdryer 30 cm above the glass cup.
13. Place the other glass cup 20 cm under the heat lamp.
57
14. Concentrate the orange juice.
17. Turn on the heat lamp.
19. Stir all orange juice containers continuously to make sure the temperature is uniform.
20. Measure the temperature of each container of orange juice and record the results on
the data sheets.
21. Record any observations you may make during the course of your experiment.
22. After 40 minutes, turn off all heating equipment.
23. Measure and record the final mass of the orange juice heated by the hot plate.
24. Measure the final volume of the orange juice heated by the hot plate by pouring the
orange juice into a graduated cylinder and recording the results.
26. Pour the orange juice into a cup and label it with your name and the method of
heating.
27. Place the orange juice in the refrigerator overnight. (Or cool by placing in an ice bath
for 5 minutes.)
28. Taste the orange juice and rate on a scale of 1 – 5, where 1 tastes the best and 5 tastes
the worst.
29. Measure and record the final mass of the orange juice heated by the hair dryer.
30. Measure the final volume of the orange juice heated by the hair dryer by pouring the
heating.
for 5 minutes.)
the worst.
35. Measure and record the final mass of the orange juice heated by the heat lamp.
36. Measure the final volume of the orange juice heated by the heat lamp by pouring the
heating.
for 5 minutes.)
the worst.
41. Calculate the mass of the juice and the starting and ending densities.
58
STUDENT WORKSHEET
Name _________________________
Date ___________________
Activity #2: Heat Transfer in the Production of Orange Juice
Procedure for the Hair Dryer Method
Materials:
triple beam balance
thermometer
stopwatch
funnel
glass cup
ring stand
masking tape
orange juice
metal spoon
safety glasses
graduated cylinder
metric ruler
paper towels
ice bath (in a cooler)
Part A: Procedures for hair dryer method:
1. Measure and record the mass of the measuring
cup.
2. Pour 200 mL of orange juice into the measuring cup.
3. Measure and record the mass of the measuring cup with orange juice in it.
4. Pour the 200 mL of orange juice into the glass cup.
5. Before placing cups under heating equipment make sure it is turned OFF!
6. Place the hairdryer 30 cm above the glass cup. The hair dryer must be placed at
least 30 cm above the cup or else the juice will be blown out of the container.
7. Ask the teacher to check your experimental set-up before turning on the heat
source.
10. Stir the orange juice continuously with a metal spoon to make sure the
temperature is uniform. (Do not stir with the thermometer or you’ll break it!) Use
an oven mitt to handle the spoon, since it will get warm over time.
11. Record the exact time and temperature of the orange juice, starting at “0 minutes,”
and record approximately every 2 minutes on the data sheets.
NOTE: In order to take an accurate measurement, the bulb of the thermometer
must be completely submerged in the orange juice. Keep the thermometer
submerged until the temperature is stable.
12. Record any other observations you make during the experiment. This may include
steam rising from the liquid and color and consistency changes in the liquid.
13. After 20 minutes, turn off the heating equipment.
59
Part B: Reconstituting the Orange Juice (AFTER heating is done)
1. Measure and record the final mass of the orange juice after heating.
2. Measure and record the final volume of the orange juice by pouring it into a
measuring cup.
3. Calculate the density of the orange juice both BEFORE and AFTER heating.
(mass of the measuring cup with orange juice) – (mass of the measuring cup) =
mass of the orange juice
4. While the orange juice is in the measuring cup, add water, enough to make the
total volume of the reconstituted orange juice equal to 200 mL.
heating.
7. Taste the orange juice and rate on a scale of 1 – 5, where 1 tastes the best and 5
tastes the worst.
60
STUDENT WORKSHEET
Name _________________________
Date ___________________
Procedure for the Hot Plate Method
Materials:
triple beam balance
thermometer
stopwatch
funnel
stainless steel pot
measuring cup
masking tape
orange juice
metal spoon
safety glasses
graduated cylinder
paper towels
oven mitt
Part A: Procedures for hot plate method:
1.
2.
3.
4.
5.
Measure and record the mass of the measuring cup.
Pour 200 mL of orange juice into the measuring cup.
Measure and record the mass of the measuring cup with orange juice.
Pour 200 mL of orange juice into the stainless steel pot.
Make sure it is turned OFF! Place the stainless steel pot on the center of the hot
plate.
6. Ask the teacher to check your experimental set-up before turning on the heat
source.
temperature is uniform. (DO NOT stir with the thermometer or you’ll break it!)
Use an oven mitt to handle the spoon since it will get warm over time.
10. Record the exact time and the temperature of the orange juice, starting at “0
minutes,” and record approximately every 2 minutes on the data sheets.
11. Record any observations you may make during the course of the experiment. This
may include steam rising from the liquid and color and consistency changes in the
liquid.
12. After 20 minutes turn off the heating equipment. Go to part B.
61
measuring cup.
3. Calculate the density of the orange juice both BEFORE and AFTER heating.
4. While the orange juice is in the measuring cup, add enough water to make the
heating.
tastes the worst.
62
STUDENT WORKSHEET
Name _________________________
Date ___________________
Procedure for the Heat Lamp Method
Materials:
triple beam balance
thermometer
stopwatch
funnel
glass cup
ring stand
masking tape
oven mitt
orange juice
metal spoon
safety glasses
graduated cylinder
metric ruler
paper towels
Part A: Procedures for heat lamp method:
1.
2.
3.
4.
5.
Measure and record the mass of the measuring cup.
Pour 200 mL of orange juice into the measuring cup.
Measure and record the mass of the measuring cup with orange juice.
Pour 200 mL of orange juice into the glass cup.
Before placing cups under heating equipment make sure it is turned OFF! Place
the heat lamp 20 cm above the glass cup.
6. Ask the teacher to check your experimental set-up BEFORE turning on the heat
source.
temperature is uniform. (DO NOT stir with the thermometer or you’ll break it!)
Use an oven mitt to handle the spoon, since it will get warm over time.
10. Record the EXACT time and the temperature of the orange juice, starting at “0
minutes,” approximately every 2 minutes on the data sheets.
steam rising from the liquid and color and consistency changes in the liquid.
12. After 20 minutes, turn off the heating equipment.
63
measuring cup.
3. Calculate the density of the orange juice both before and after heating.
4. While the orange juice is in the measuring cup, add enough water to make the
heating.
7. Taste the orange juice and rate it on a scale of 1 – 5, where 1 tastes the best and 5
tastes the worst.
64
STUDENT WORKSHEET
Name _________________________
Activity #2: Data Sheet 1
Date ___________________
Part A: Concentrating the Orange Juice Data Sheet
Type of heating unit:________________ Type of heat transfer:_________________
Recorder: ____________
Stirrer: ______________
Timer: ______________
Temperature Taker: _______________
1. Mass of container:__________________
2. Starting volume of orange juice:__________
3. Mass of container and juice:__________
Time
(hr:min:sec)
Temperature
(oC)
Observations
65
STUDENT WORKSHEET
Name _________________________
Activity #2: Data Sheet 2
Date ___________________
Part B: Reconstituting the Orange Juice Data Sheet
Type of heating unit:___________________
1. Mass of container:______________________
2. Ending volume of orange juice:__________
3. Mass of container and juice:__________
Calculations and Results:
1. Starting Density of Juice:
Density =
Starting Mass of OJ
Starting Volume of OJ
=
___________
=
____________
2. Ending Density of Juice:
Density = Ending Mass of OJ =
Ending Volume of OJ
_________________
3. Volume added to reconstitute juice:________________
66
=
____________
Conclusions
At the end of this activity students should:
1. Identify heat from the heat lamp as radiation, heat from the hairdryer as
convection, and heat from the hotplate as conduction.
2. Understand that by evaporating a homogeneous mixture the density and the
concentration increase.
3. Determine that the hotplate removes the largest amount of water the fastest.
Vocabulary
Boiling point: the temperature at which a liquid becomes a gas
Conduction: the transfer of thermal energy between particles within a substance
Convection: the transfer of thermal energy by the movement of currents within a fluid
Evaporation: the process that occurs when vaporization takes place only on the surface
of a liquid
Heat transfer: the transfer of thermal energy by conduction, convection, or radiation
Heat: the movement of thermal energy from one substance to another
Radiation: the transfer of energy by electromagnetic waves
Temperature: the measure of the average kinetic energy of the particles in a substance
References
1. Frozen Concentrated Orange Juice from Florida Oranges
http://www.ultimatecitrus.com/pdf/fcoj.pdf
2. Science Explorer: Physical Science. Upper Saddle River, NJ: Prentice Hall, 2002.
440 – 442.
Extensions
Reducing the Activity Time:
Students can run the heating units for 20 minutes instead of 40 minutes, but they will
need to be more careful with their post-measuring volume readings since the decrease in
volume will be smaller. The teacher will then have to prepare 40 minute concentrated
samples ahead of time for the class to taste test.
67
Excel
Students can use Microsoft Excel to graph results instead of graph paper.
Density
The density of the orange juice before and after condensing can be determined by using
the equation: density = mass/volume. This will show students how concentrating the
orange juice affects the density.
Before Heating
Density = Mass of the OJ before heating
Volume of the OJ before heating
After Heating
Density = Mass of OJ before heating – Mass of OJ directly after heating
Volume of OJ after heating
Another Possible Heat Transfer Device:
A microwave can be used to show radiation instead of the heat lamp.
Procedures for microwave method:
1. Measure and record the mass of the measuring cup.
2. Pour 200 mL of orange juice into the measuring cup.
3. Measure and record the mass of the measuring cup with orange juice in it.
4. Pour 200 mL of orange juice into the microwave-safe, glass cup.
5. Place the glass cup in the microwave.
6. Ask the teacher to check your experimental set-up BEFORE turning on the heat
source.
7. Turn on the microwave on high for 40 minutes.
steam rising from the liquid or color changes and consistency changes in the
liquid.
9. After 40 minutes turn off the heating equipment.
10. Measure and record the final mass of the orange juice heated by the microwave.
11. Measure the final volume of the orange juice heated by pouring the orange juice
into a graduated cylinder and recording the results.
heating.
tastes the worst.
Note: The students will not be able to record the temperature during the heating process.
68
Part 3: Flowsheets: One of an Engineer’s Communication Tools
Learning Strand:
Materials, Tools, and Machines
Engineering Design
Communication Technologies
Concepts:
Symbols
Procedures/Instructions
Effective Engineering Communication
Planning on paper or building a prototype
as a design step in the engineering process.
Preparation Time:
60 minutes
Activity Time:
90 minutes
Time Required – 2 class periods. Class period 1: Intro to flowsheets and whipped cream
demonstration. Class Period 2: New snack food activity and wrap-up discussion.
Level of Difficulty: 3
Group Size: groups of 2
Purpose
The purpose of this activity is to introduce students to manufacturing processes and to the
use of flowsheets as an important communication tool for engineers. In “Flowsheets: One
of an Engineer’s Communication Tools,” students will:
1) Identify manufacturing processes they are familiar with.
2) Understand that a process consists of equipment, tools, and the procedures of
how to operate the equipment and tools to make a desired product.
3) Understand that a flowsheet contains symbols for equipment and tools,
identifies steps and connections between equipment, identifies raw materials,
and identifies process variables.
4) Create a flowsheet composed of symbols and procedures to communicate a
manufacturing process.
5) Use a flowsheet of a manufacturing process to make a product.
6) Understand the importance of the engineering design steps, which include
developing solutions and a prototype before actually making a product.
69
Outcomes
1) Identify a manufacturing process
2) Develop a flowsheet and a procedure for a simple manufacturing process they
are familiar with
3) Identify raw materials and process variables in a flowsheet
4) Follow a flowsheet and procedure to produce a product
5) Recognize a flowsheet of an orange juice concentration process
6) Understand how to use a flowsheet in the design process
Other skills practiced in this activity include logical thinking, analytical thinking, and
effective communication.
CONNECTIONS TO “THE GREAT ORANGE SQUEEZE”: Engineers use science
to make products that solve our society’s problems. Many products are made through a
manufacturing process. In “The Great Orange Squeeze,” the students, as engineers, make
concentrated orange juice through an evaporation and condensation manufacturing
process to provide low cost, good tasting orange juice to kindergarten breakfast programs
in Boston. Students have already discovered the science of heat transfer (Activity 2) and
learned that conduction is the most efficient way to transfer heat to the orange juice with
our tools. They are now ready to use this information to help them solve the challenge.
CONNECTIONS TO THE ENGINEERING DESIGN PROCESS:
There are eight steps in the engineering design process:
1.
2.
3.
4.
5.
6.
7.
8.
Test and evaluate
Redesign
Design steps 3 (develop possible solutions), 4 (select the best possible solution), 5
(construct a prototype), 7 (communicate the solution), and 8 (redesign) all involve
creating and testing ideas and communicating those ideas to others. Flowsheets are one of
the tools that engineers use to communicate their ideas. Flowsheets are like directions of
how to make the product, and they include both symbols pictorially representing the idea
70
and written words giving information and directions, called procedures. At the end of this
activity, students will be ready to prototype their orange juice concentration processes by
using a flowsheet and the prototype supplies (Activity 4).
OVERVIEW OF THIS ACTIVITY: In “Flowsheets: One of an Engineer’s
Communication Tools,” students will first discover what a manufacturing process is and
observe a flowsheet being used through discussion and the whipped cream
demonstration. Students will also be exposed to an industrial-scale manufacturing orange
juice concentration process (through either a tour or a virtual tour). Then the students, in
groups of two, will create a flowsheet for making a new snack food. The groups will then
swap flowsheets and try to follow them to make the desired product (a new snack food).
Background for Teacher
Engineers use science to make products that solve our society’s problems. Many products
are made through a manufacturing process. In “The Great Orange Squeeze,” the students,
as engineers, make concentrated orange juice through an evaporation and condensation
manufacturing process to provide low cost, good tasting orange juice to kindergarten
breakfast programs in Boston.
Students are now ready to be engineers and use what they have learned from science to
help them solve the problem of providing orange juice in an affordable way. The next
step engineers need to take is to develop possible solutions and evaluate them, and then
design and prototype their best solution. Flowsheets are used in all of these steps, as well
as in the final step of redesign. Flowsheets are like directions of how to make the product,
and they include both symbols pictorially representing the idea and words giving
information and directions, called procedures. So, before the students can begin to design
possible solutions to the condensation of orange juice, they need to understand what a
manufacturing process is and how to communicate designs and ideas about
manufacturing processes through flowsheets.
What is a Manufacturing Process?
A manufacturing process is a collection of tools or machines, the connections between
them, and how the tools are used together to produce a product. Manufacturing processes
are used to produce everything from anti-cancer drugs to ballpoint pens. The
manufacturing process starts with raw materials and converts those materials into a useful
product. How the tools or machines are used together to produce a product is called the
procedure for the process. Procedures can be thought of as directions that contain
important information about how the process is to be operated. This important
information includes process variables like temperature, pressure, and flowrates, as well
as safety information like “thermal gloves should be worn because pipes get very hot.”
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An analogy for a manufacturing process that the students will be familiar with is the
process of preparing food. Baking a cake from a mix is a manufacturing process where
eggs and oil are two of the raw materials. The procedure for baking a cake includes
specified amounts of eggs and oil, as well as other ingredients, that are mixed together in
a specific way. The batter is then baked in a tool (oven) for a specific amount of time at a
specific temperature, and oven mitts are used for safety when removing the cake from the
oven.
Other considerations in a manufacturing process include the cost of each step, the
environmental impact of each process step, and the quality of the product. To continue
with the cake baking analogy, the cost and quality balance can be seen in whether you
choose to by organic or generic ingredients and how that impacts both the cost of the
cake and its flavor. The environmental impact can be illustrated by considering what
happens to the residual batter when the mixing bowl is washed. The sewage treatment
system destroys the harmful bacteria in raw eggs before the rinse water is discharged to
the ocean. The concepts of cost and quality will be further explored in Activities 4 and 5.
What is a Flowsheet?
Flowsheets are one of the tools that engineers use to communicate their ideas. Flowsheets
are like directions of how to make the product, and they include both symbols pictorially
representing the idea and words giving information and directions, called procedures.
When engineers design processes based on science, they start by designing on paper. On
paper, the engineers use flowsheets to communicate both the machines and procedures
used in the process. It is very important for engineers to be specific and clear and to
consider all aspects of the process: equipment, steps to take (procedures), raw materials
(what you start with), safety, and environmental impact.
Examples of two flowsheets are given in Figures 1 and 2, from a simple example to a
more complex example. The goal of all flowsheets is to clearly and specifically
communicate a process. As long as this goal is met, there is a lot of flexibility for the
students to explore in developing their flowsheets. Note that in each flowsheet there are
eight key elements:
1.
2.
3.
4.
5.
6.
7.
8.
Symbols/pictures
Key or legend
Procedures
Order
Raw materials
Tools
Process variables
Safety and environmental impact
72
5. Raw Materials
2. Key
Ingredients
3 Large
Eggs
1 1/3 cup
Water
½ Cup Oil Dry Mix
3. Procedure
4. Order
1
Directions for Baking
7. Process
Preheat oven to 350°F.
Grease and lightly flour baking pan. Variables
6. Tools
2
Mix ingredients together in a bowl for 30 sec at low
speed.
Beat ingredients for 2 minutes on high speed.
Pour contents of bowl into baking pan and place in
oven.
1. Picture
3
Bake for 30 minutes, or until a toothpick inserted in
the center comes out dry. Cool for 15 minutes.
Handle hot objects with oven mitts.
8. Safety
Figure 1: Simple Flowsheet for
Baking a Cake
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1. Picture
5. Raw Materials
Water
Washing
Sorting
Grading
Fruit Unloading
Blending
Water Reuse
4. Order
Refrigerated
Tank
(Concentrated
&Fresh Juice)
Concentrate
Evaporator
Juice Extractor
Fresh Juice
Addition
Freezer
-15°C
Can Filler
2. Key
Pulp and Peel to Animal
Feed and Fertilizer
3. Procedure
Distributor
7. Process
Variables
6. Tools
Note: Evaporator and Concentrate
Tank are HOT. Use protective
thermal safety gloves when
operating manual valves.
8. Safety
Figure 2: More Complex Flowsheet for
Producing Concentrated Orange Juice
This sketch is based on the flowsheet of Richard F. Matthews, Frozen Concentrated
Orange Juice from Florida Oranges, Fact Sheet FS 8, a series of the Food Science
and Human Nutrition, Florida Cooperative Extension Service, Institute of Food and
Agricultural Sciences, University of Florida. Publication date: April 1994. See the
following website for more information: www.ultimatecitrus.com/pdf/fcoj.pdf.
74
Figure 3: Example of a Poor Flowsheet for
Making Whipped Cream
Add cream to a bowl.
Cream
75
Taste
Sugar
Mix
Add a capful of vanilla.
Add two pinches of sugar into the
bowl.
Example of Poor Flowsheet
Flowsheet for Making Whipped Cream:
Time: 5 min
Temp: 4ºC
Speed: High
Mixer
Cream
Figure 4: Example of a Good Flowsheet for
Making Whipped Cream
Sugar
Vanilla
•
•
•
•
•
•
•
•
•
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Put on safety glasses.
Check to make sure mixer is NOT
plugged in.
Add 1 pint of 4ºC whipping cream to
a chilled 2-liter stainless steel bowl.
Add 3 teaspoons granulated white
sugar.
Add a ½ tsp of vanilla.
Place bowl on mixer stand. Lower
beaters into bowl and lock into place.
Plug in electric mixer and mix on high
speed for 5 minutes.
Unplug mixer, unlock and remove
beaters, and wipe beaters clean.
Using a spatula, remove the whipped
cream and place on partner’s nose.
Example of Good Flowsheet
Flowsheet for Making Whipped Cream:
Orange Juice Manufacturing Process
There are several types of orange juice manufacturing processes corresponding to the
several types of orange juice that are available in the grocery store: fresh, pasteurized,
reconstituted, and frozen. A brief description of each of the types and the manufacturing
process for each type is provided in the Teacher’s Background of Activity 1. The frozen
orange juice manufacturing process is repeated and expanded here for convenience.
What is Frozen Concentrate of Orange Juice?
Juice from oranges with 75% of the water removed and some small amount of fresh juice
mixed in is called concentrate. Frozen concentrate comes in plastic containers or
cardboard and metal containers. Freezing the concentrate extends the shelf life of orange
juice up to two years. To serve, the juice must first be mixed with water to reconstitute it.
While concentrating does affect the flavor, removing water reduces the cost to ship the
product to its final destination. By removing 75% of the water through the concentration
process, the cost to the consumer decreases by 85%.
How Do They Make Frozen Concentrate of Orange Juice?
Below is a simplified procedure for producing frozen concentrate. (This procedure is
from www.floridajuice.com/floridacitrus/whereojbar.htm.)
1) Oranges are picked from trees and brought to the orange juice manufacturing
plant.
2) Oranges are washed and sorted so that only high-quality, clean oranges are
sent to the juicing machines.
3) Oranges are squeezed in the juice extractors.
4) Strainers are used to remove seeds, peel, and pulp.
5) Pieces of peel and sometimes pulp are dried to make cattle feed.
6) The fresh juice without the peel and pulp is fed to evaporators. Evaporators
are used to remove the water from the juice. Orange juice concentrate is made
by heating orange juice for an extended period to remove the natural water.
(Since orange juice is a heterogeneous mixture its components can be
separated by their boiling points.) The water that is removed is recycled and
reused to wash the fresh fruit (raw materials) in step 2.
7) Fresh juice, from before the evaporation stage, is added to the concentrate. As
the water evaporates from the juice, the heat destroys delicate compounds in
the mixture and gives the juice a “cooked flavor.” In order to combat the
“cooked flavor” after concentration, engineers add a small amount of fresh
juice to the concentrate.
8) Juice is chilled to form a slush.
9) Slush concentrate is packaged in plastic or cardboard containers.
10) Concentrate is frozen and shipped to its final destination.
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Orange Juice Flowsheet
The best way to communicate the frozen concentrate orange juice manufacturing process
is pictorially through a flowsheet. Below is a flowsheet describing the above procedure.
Water
Washing
Sorting
Grading
Water Reuse
Fruit Unloading
Blending
(Concentrated
&Fresh Juice)
Refrigerated
Tank
Concentrate
Evaporator
Juice Extractor
Fresh Juice
Addition
Freezer
-15°
Can Filler
Distributor
Feed and Fertilizer
thermal safety gloves when operating
manual valves.
Websites that contain background information, flowsheets, and pictures are available at
the following locations: www.ultimatecitrus.com/pdf/fcoj.pdf and
www.floridajuice.com/floridacitrus/whereojbar.htm.
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Materials
Demonstration
•
•
•
•
•
•
•
•
1 pint of whipping cream
2 tablespoons of sugar
thermometer
timer
spatula
bowl
mixer
vanilla
Activity
Per group of 2 students or more
• worksheet
• pen or pencil
• ruler
• spoon
• food coloring
(Other materials may be substituted based on availability.)
Maximum of one serving each:
• jelly beans
• chocolate
• licorice
• candy-covered chocolate
• marshmallows
One of either:
• apple
• 2 graham crackers
One of either:
• whipping cream
• frosting
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•
Read through background for an introduction to flowsheets.
•
Set up for the whipped cream demonstration:
1. Choose a demonstration area that has a power outlet.
2. Gather all materials and store in a refrigerator until ready to use.
3. Print out examples of good and poor whipped cream demonstration flowsheets.
•
Set up for the snack activity:
1. Identify the workstations to ensure that students have enough space to operate the
activity.
2. Gather materials. All materials must be clean so that the students can consume the
product. If possible these materials should be strictly dedicated to the orange juice
kit.
3. Set up workstations. This activity can be run in either a lab or a classroom. The
materials should be distributed to activity stations in advance to save classroom
time.
4. Print worksheets. One worksheet should be printed for each group of at least 2
students.
Doing the Activity
When engineers design processes based on science, they start by designing on paper.
Their plans include symbols and flowsheets to communicate both the machines used and
the procedure used in the process.
Show examples of flowsheets to your students and talk through the process steps. It is
very important to be specific and clear and to consider all aspects of the process:
equipment, steps to take (procedures), raw materials (what you start with), safety, and
environmental impact. In the introduction to this activity, be sure to stress that when you
are following someone’s procedure, you follow it exactly!
The lecture should address these three key questions:
1. What do engineers do?
Engineers use science to make products that solve our society’s problems.
2. What is a manufacturing process?
A manufacturing process is a collection of tools or machines, the connections
between them, and how the tools are used together to produce a product.
80
3. How do engineers communicate their ideas about a manufacturing
process?
They use flowsheets and procedures.
4. Look at some flowsheets and procedures and discuss the key features.
1. Symbols/pictures
2. Key or legend
3. Procedures
4. Order/direction
5. Raw materials
6. Tools
7. Process variables
8. Safety and environmental impact
It is recommended that students take a fieldtrip to a local manufacturing plant. (See the
Extensions section for more information.) However, if such a trip is not feasible, see the
following website for pictures that give a better idea of what orange juice processing
equipment looks like: www.floridajuice.com/floridacitrus/whereojbar.htm.
81
Whipped Cream Process
By demonstrating the use of a flowsheet for making whipped cream, students can begin
to see the value of flowsheets as a communication tool as well as the importance of
making flowsheets as clear and specific as possible. A demonstration that includes
following a well-defined flowsheet and a faulty one can be a fun and valuable learning
experience.
Some examples for faulty flowsheets include the following: does not have a key to
describe equipment, is drawn in the wrong order, or does not include safety information.
Some examples for faulty procedures include the following: does not include a mixer, has
you measure an ambiguous amount of sugar, or does not tell you the order of the steps.
Some tips on making whipped cream include:
1) Whipping cream must be cold (4°C), and it helps if the bowl and beaters are
chilled as well.
2) Cream must be whipped at high speed.
3) Adding sugar and vanilla improves taste.
Using the attached flowsheet and procedure (Figures 3 and 4) or something similar, show
a poor flowsheet and procedure and demonstrate following it. Then show the attached
good flowsheet and procedure and demonstrate following it. After the demonstration, the
students should discuss what was wrong with the faulty flowsheet and what was right
with the well-defined flowsheet. They should reference the eight key elements for a
flowsheet and identify them on the two flowsheets.
New Snack Flowsheet
This exercise gives the students a chance to practice making a flowsheet on a simple
manufacturing process that they are familiar with. Then they practice making a product
by following another group’s flowsheet. Any process that the students can design a
flowsheet for, and can reproduce from a flowsheet, in the allotted time may be substituted
for the snack exercise. Other examples: brushing your teeth, making S’mores, dancing
the Hokie Pokie, building with blocks, etc. See the Extensions section for a “Make a Pet
Hero” challenge.
In the introduction to this activity, be sure to stress that when you are following
someone’s procedure, you follow it exactly! As described in the Extensions section,
allowing the students to present their creations from another’s group flowsheet, or
comparing digital pictures of the intended and the actual creations, can be both fun and
enlightening for the students. Student often want to re-engineer their flowsheet when they
see what another group has produced from their original flowsheet.
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1) Present challenge:
New Snack Challenge:
You are a design engineer for the Holiday Candy Company. Your job is to
create a new holiday treat for eighth graders across the globe. You must
design the snack and how to make it (the snack process) so that your
company can produce your snack. As a good engineer, you know that first
you must create possible snack ideas and choose the best one. Then, you
need to design your snack process and test your snack process to see if it
works. To test your snack process you must create a flowsheet of your
process and see if the senior process engineer (another group) can make
your snack according to your intended design.
2) Pair the students in groups of two.
3) Show all possible materials for the snack and explain any rules.
Example: The following foods are available: graham crackers, jelly beans,
an apple, whipped cream, chocolate, frosting, licorice, candy-covered
chocolate, and marshmallows. Either an apple or two graham crackers,
either one serving of frosting or one serving of whipped cream, and one
serving per group of all other materials may be used.
4) Ask each group to draw a flowsheet for making their new holiday snack food.
Groups may play with the allotted material as they are creating their snack and
their flowsheet. Worksheets are provided to aid in this task. Large pieces of
butcher paper work well for flowsheets.
5) When the students have completed the task, the groups swap flowsheets.
6) The students must then make the snack from another group’s flowsheet
(following it exactly!). A worksheet is provided to help students evaluate each
other’s flowsheets.
7) After they have assembled their snack, the students should decide if the flowsheet
was successful. This can be done through presentations, sharing pictures, or just
class discussion.
8) Finally, the students can eat their products.
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Connections to The Great Orange Squeeze
To wrap up this activity a connection needs to be made between the holiday snack
activity and concentrating orange juice. Returning to the discussion on manufacturing
processes, most manufacturing processes begin on the benchtop, meaning that the process
is done on a small enough scale to be done on a table. From there the process is made into
a larger producing process called a scale-up, and then if that is successful, it is made into
a full manufacturing process, producing mass quantities of the product. The snack
process is similar to the benchtop process of squeezing orange juice. All you need to
produce a glass of orange juice is a reamer, a strainer, oranges, and a cup. A scale-up
model may include powering the reamer instead of using your hand, having a larger
strainer and container, and using more oranges. The scale-up model will produce one to
two gallons of orange juice. The manufacturing process automates most of these actions
and produces half a million gallons of juice per day.
Activity 4 will require the students to design a prototype (Step 5 of the Engineering
Design Process) of a process to concentrate their orange juice by choosing the best heat
transfer method based on the results of Activity 2. Using what they have learned from
this activity, the students must also create a flowsheet and procedure for their process. A
review worksheet is provided as part of the Extensions section to help prepare the
students for Activities 4, 5, and 6.
84
Procedure
Materials:
• worksheet
• ruler
• food coloring
• pen or pencil
• spoon
Maximum of one serving each:
• jelly beans
• chocolate
• licorice
• candy-covered chocolate
• marshmallows
One of either:
• apple
• 2 graham crackers
One of either:
• whipping cream
• frosting
Procedure:
1. Read the design challenge:
You are a design engineer for the Holiday Candy Company. Your job is to
create a new holiday treat for eighth graders across the globe. You must
design the snack and how to make it (the snack process) so that your
company can produce your snack. As a good engineer, you know that first
you must create possible snack ideas and choose the best one. Then, you
need to design your snack process and test it to see if it works. To test your
snack process you must create a flowsheet of your process and see if the
senior process engineer (another group) can make your snack according to
your intended design.
2. Draw a flowsheet on the poster paper for a new holiday snack. Be sure to include
the eight key elements for a flowsheet. Remember to be specific; someone will
have to follow your directions!
3. After you have completed your flowsheet, give it to another group to follow to
make your snack.
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4. You will receive a flowsheet from another group. Follow it to make their snack.
Answer these questions on the back of their flowsheet:
a. Does it have the eight key elements? If not, what is it missing?
b. Are the pictures clear? What would help you understand them better?
c. Is the procedure clear? What would make it easier to understand?
5. When you have made the snack and completed the questions, return the flowsheet
to the originators.
6. Check to see if your flowsheet and procedure produced the desired snack. If not,
make the appropriate changes to your flowsheet and procedure. Look at the
comments on your flowsheet and make the appropriate changes.
86
STUDENT WORKSHEET
Name _________________________
Activity #3: Flowsheets 1
Date ___________________
1. What are the eight key features in a flowsheet?
1. ________________________________________________
2. ________________________________________________
3. ________________________________________________
4. ________________________________________________
5. ________________________________________________
6. ________________________________________________
7. ________________________________________________
8. ________________________________________________
2. Give three examples of a flowsheet:
3. List three ideas for a holiday snack:
Note – update worksheets!
Flowsheet
87
STUDENT WORKSHEET
Name _________________________
Date ___________________
Group #:________________
Group Roles:
Group Leader Name:________________
People working on Sheet 1:__________________________________________
People working on Sheet 2:__________________________________________
Holiday Snack Company
1. Name of your snack:
2. Check to be sure you have all the key elements in your flowsheet:
Sheet 1
Sheet 2
1.
2.
3.
4.
5.
6.
7.
8.
Symbols/Pictures
Key or Legend
Raw Materials
Tools
Procedures
Order/Direction
Process Variables
Safety and
Environmental Impact
88
STUDENT WORKSHEET
Name ___________________________
Date _____________
Classwork
Evaluation of Flowsheet: Period ______ Group # ______
Name of Design: __________________________________
Directions: After building the snack from the flowsheet, circle your rating of the
flowsheet that you are testing.
1. Procedures and Order
Missing
Poor
Satisfactory
Excellent!
2. Pictures and Key
Missing
Poor
Satisfactory
Excellent!
3. Raw Materials and Tools Missing
Poor
Satisfactory
Excellent!
4. Safety/Environmental Impact
Missing
Poor
Satisfactory
Excellent!
COMMENTS
A) Describe the TWO BEST FEATURES of the flowsheet:
I.
II.
B) Give YOUR TWO BEST SUGGESTIONS to improve the flowsheets (NOT the
design of the product, but the flowsheet itself):
I.
II.
89
Conclusions
By the end of this activity, students should:
1. Identify a manufacturing process as a collection of tools or machines, the
connections between them, and how the tools are used together to produce
a product.
2. Develop a flowsheet and a procedure for manufacturing a new holiday
treat.
3. Identify the raw materials and process variables in their holiday treat
flowsheet.
4. Follow a flowsheet and procedure to produce a holiday treat.
5. Recognize a flowsheet of an orange juice concentration process.
Vocabulary
Flowsheet: Directions of how to make a product. Includes both symbols
pictorially representing the idea and written words giving information and
directions.
Manufacturing Process: A collection of tools or machines, the connections
between them, and how the tools are used together to produce a product.
Procedure: Written directions that follow the flowsheet.
Process Variables: Quantities that must be controlled in the process.
Raw Materials: The starting materials, which are turned into useful product.
References
Websites on Orange Juice:
www.minutemaid.com
www.tropicana.com/biz/about/process.htm
www.floridajuice.com/floridacitrus/whereojbar.htm
Websites with Flowsheets:
www.xbox.com/en-US/support/hardware/xboxconnect.htm
www.floridajuice.com/floridacitrus/whereojbar.htm
90
Extensions
Multiple Design Attempts
Depending on the length of time allowed for the activity, the groups can explore the
element of choosing the best design from multiple designs, as part of the engineering
process. This concept is also explored in Activities 4 and 6 but can be added to Activity 3
to more completely cover the engineering design process steps 1 through 8. (See
Overview and Connections section.)
Presentation of Results
Have students give presentations on following another group’s flowsheet. If possible,
take digital pictures of the intended snack and the actual snack after following the
flowsheet. Students will really benefit from actually seeing what their snack was
supposed to look like. If time permits, let students redesign their flowsheets.
Possible Performance Assessment Activity
Students can develop flowsheets based on Activity 2 instead of on a new snack. Split the
class into groups for the hot plate, heat lamp, and hair drier or have all groups work on
the hot plate apparatus. Give each group all the materials used in Activity 2 for each setup. Students will work together to determine how to set up the apparatus and design a
flowsheet. If all three heat transfer set-ups are used, have students share their flowsheets
with the class. Make sure to focus on the hot plate flowsheets since students will use this
material for the rest of the activities.
Locations in Massachusetts for Manufacturing Field Trips:
Boston:
Deer Island: sewage treatment plant
Littleton:
Veryfine: juice manufacturer
Review Quiz
The following three pages are quizzes or homework assignments used to review the first
three activities in preparation for Activities 4, 5, and 6.
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STUDENT WORKSHEET
Name __________________________
Class____________
Date ___________________
Review (1 – 3)
The Great Orange Squeeze: Understanding Concepts in Activities 1 – 3
1. Describe the challenge presented by The Great Orange Squeeze.
2. List the steps for the engineering design process. Describe how each specifically
relates to the challenge of The Great Orange Squeeze.
3. What are the eight key features that are present in a well-made flowsheet?
4. Determine the cost of shipping an 8-ounce glass of orange juice from Florida to Boston
according to the cost/pound ($/lbs.) for each mode of shipping. (Note: density of orange
juice = 1g/mL.) Hint: How many ounces of orange juice are in 1 lb.?
BOAT:
PLANE:
TRAIN:
TRUCK:
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5. What VOLUME of orange juice can you ship for $.25 according to the cost of for each
mode of shipping?
BOAT:
PLANE:
TRAIN:
TRUCK:
6. How can you reduce the weight of the orange juice? How much of this substance
would have to be removed in order to have an 8-ounce glass cost only $.25 for each mode
of shipping?
BOAT:
PLANE:
TRAIN:
TRUCK:
93
7. At an orange juice manufacturing plant in Florida, 1million gallons of orange juice are
produced every day. How many gallons of water are produced to concentrate an 8-ounce
glass for each mode of shipping?
BOAT:
PLANE:
TRAIN:
TRUCK:
8. What do you propose should be done with all the water extracted from the juice when
concentrating it?
94
Part 4: Orange Concentration Flowsheet and Prototype I
Learning Strand:
Engineering Design
Concepts:
Symbols
Planning on Paper or Building a Prototype
Preparation Time:
60 minutes
Activity Time:
90 minutes
Time Required: 2 class periods
3
Group Size:
4 to 5 students
Purpose
The purpose of this activity is to have the students apply what they have learned about
flowsheets and processes in Activity 3 to create a flowsheet and a prototype of the
concentration process based on what they learned from science in Activity 2. In “Orange
Concentration Flowsheet and Prototype I,” students will:
1. Apply the science from Activity 2 to determine the best possible solution for
heating their orange juice;
2. Apply the science from Activity 2 to design a prototype orange juice
concentration process;
3. Create a flowsheet composed of symbols and procedures to communicate their
process;
4. Begin to understand the relationships among the process, the product cost, and
the product quality;
5. Discover the need for more science to complete their flowsheet and prototype;
and
6. Understand the importance of engineering design steps 3, 4, and 5, which
include developing solutions, selecting the best solution, and developing a
prototype before actually testing a solution or making a product.
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Outcomes
1. Choose the best possible heat transfer mechanism for the orange juice
concentration process;
2. Show a preliminary prototype for the orange juice concentration process;
3. Show a preliminary flowsheet and procedure for the prototype process;
4. Discuss the information needed to complete the flowsheet and the prototype;
and
5. Discuss the impact of the process on the cost and quality of the orange juice
product.
Other skills practiced in this activity include logical thinking, analytical thinking, group
decision-making, and effective communication.
CONNECTIONS TO “THE GREAT ORANGE SQUEEZE”: At this point the
students understand the shipping weight-to-cost relationship and have decided that
juice to kindergarten breakfast programs in Boston. They have played the role of scientist
to discover characteristics of the three forms of heat transfer (conduction, convection, and
radiation), and have observed the heating of orange juice. They have learned about
processes, flowsheets, and procedures. Students are now ready to become engineers and
use the science they learned about heat transfer to help them solve the problem of getting
low cost, good-tasting orange juice from Florida to Boston.
This activity leads into Activity 5 by providing the motivation for needing to understand
more science in order to specify the process variables needed for a complete flowsheet
and procedure. This activity also introduces the impact of process design choices on
product cost and quality. The concept of the process impact on cost and quality is
reinforced in Activity 5.
CONNECTIONS TO THE ENGINEERING DESIGN PROCESS: Design steps 3
(Develop possible solutions), 4 (Select the best possible solution), 5 (Construct a
prototype), 6 (Test and evaluate), and 7 (Communicate solutions) are illustrated and
practiced in this activity. Students must develop possible solutions for the heating process
to concentrate their orange juice (Step 3) and choose the best one (Step 4) based on what
they learned in Activities 2 and 3. Students construct a preliminary flowsheet and
prototype (Step 5) for their best solution. They then evaluate their solution and realize
that they need more information about process variables in order to solve the problem
(Step 6). At the end of this activity, students will be ready to “go back to science” to
96
discover the time and volume and taste relationships with heating the orange juice to
remove water (Activity 5). This reinforces the message that science and engineering are
different and interrelated careers.
OVERVIEW OF THIS ACTIVITY: In “Orange Concentration Flowsheet and
Prototype I,” the students will engineer possible solutions to how they will concentrate
orange juice using the tools available to them. They will choose the best solution based
on what they have learned about the three methods of heat transfer in Activity 2 and what
they learned about the Tropicana® process in Activity 3. Although there will be many
different possible solutions, the best solution will use the hot plate as a tool for heat
transfer by conduction based on the time versus temperature charts from Activity 2. The
students will create a flowsheet with a procedure and a prototype of their best solution.
They will evaluate their design and determine that they are missing information on
critical process variables, such as how long to heat the orange juice and how much fresh
juice to add after concentration. The class will discuss the relationship between these key
process variables and the cost and quality of the product (concentrated orange juice) in
light of the challenge to provide low-cost, good-tasting orange juice to kindergarten
breakfast programs in Boston.
The activity is outlined for several mini-breakout activities with classroom discussion
between them. Alternatively, students can be left on their own after a brief introduction.
Engineers use the science you have observed to design and build a manufacturing process
to concentrate orange juice that tastes good and can be sold at an affordable price.
Processes are designed to use science for a purpose. Now that we have some science
information, we next need to understand what a process is and what it contains so that we
can create a solution to our orange juice supply problem.
The hot plate, the hair dryer, and the heat lamp are three different tools that use the
science of heat transfer. Through discovering science (Activity 2), the students have
learned that:
1. the three methods of heat transfer (conduction by the hot plate, convection by
the hair dryer, and radiation by the heat lamp) produce different time versus
temperature curves;
2. conduction (the hot plate) is the most efficient heat transfer method to heat the
orange juice with the tools provided;
3. one consequence of heating the orange juice is that the volume of the orange
juice goes down and steam comes off the liquid; and
4. the taste of the orange juice changes as you heat it.
97
Activity 3 introduced students to the engineering communication tools of flowsheets and
procedures, as well as to a real manufacturing process for the concentration of orange
juice.
In Activity 4, the students will follow the next steps (specifically 3 – 7) in the engineering
design process so that they can ultimately design their own orange juice concentration
process.
The eight steps in the engineering design process are as follows:
1.
2.
3.
4.
5.
6.
7.
8.
Test and evaluate
Redesign
The students have already tested several systems that would condense orange juice.
However, only one system concentrated the juice in a timely fashion—the hot plate.
Students may consider this as the end of their assignment, since they have condensed the
orange juice and now all they have to do is package and freeze it to meet their cost
constraints; however, engineers need to consider several other factors before designing a
process.
In addition to taste and cost, engineers need to consider safety and the environment when
designing a process. Therefore their goals of the process should include:
• to produce concentrated orange juice
• to make sure the orange juice tastes good when used by the customer
• to make the product affordable
• to make the product safely (not hurt any workers)
• to make the product without damaging the environment
Orange Juice Concentration Process Review
Below is a schematic of a typical orange juice concentration process. The students are
going to prototype steps 9 through 12 represented in this schematic. As they develop their
prototype (which includes a flowsheet and procedure), they will realize that they do not
have enough information to meet the five goals above. They will be missing the
relationships between taste and the balance of heating time and taste and the amount of
fresh juice added. This leads them to Activity 5.
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Water
Washing
Sorting
Grading
Water Reuse
Fruit Unloading
9
Blending
(Concentrated and
Fresh Juice)
Refrigerated
Tank
Concentrate
Evaporator
1
Juice Extractor
Fresh Juice
Addition
Freezer
-15°
12
1
Can Filler
Distributor
Feed and Fertilizer
thermal safety gloves when
operating manual valves.
Steps in the production of frozen concentrated orange juice
(information from www.ultimatecitrus.com/pdf/fcoj.pdf)
Evaporation and Condensation
Evaporation occurs when matter changes from liquid to gas. Temperature affects the
evaporation rate of a liquid. At the boiling point of a liquid, the kinetic energy of the
molecules allows for dissociation from the liquid, by adding more heat energy, the
evaporation rate increases. (For more information about evaporation, see Teaching
Elementary Science: A Full Spectrum Science Instruction Approach by William and
Mary Esler.)
99
In the orange juice process, water is evaporated from the juice to concentrate the juice
sugars and solids; this decreases the weight of the product for shipping. Approximately
75% of the volume of the juice is removed as water. Once the juice reaches its final
destination (the consumer), water is then added to reconstitute the juice for drinking.
Orange juice processing plants can concentrate as much as 530,000 gallons of fresh juice
per day. (For more information about this process see www.ultimatecitrus.com/pdf/
fcoj.pdf.)
During condensation, matter changes from a vapor to a liquid. Once heat energy is
removed, the kinetic energy of the molecules decreases, and the vapor condenses into a
liquid.
Condensers are used in the orange juice process to collect the water vapor from the
evaporators. The collected water is recycled within the plant for clean-up and washing of
the fruit. Tropicana® recovers between 100,000 – 400,000 gallons of water per day
depending on the size of the processing plant. (For more information about this process
see www.tropicana.com/index.asp?ID=60.)
Taste Quality
The heat used to evaporate water from the orange juice also causes a breakdown of
several chemicals in the orange juice. This impacts the taste of the reconstituted product.
In order to ensure a good-tasting reconstituted product for the customer, concentrated
orange juice manufacturers add a small amount of fresh orange juice to the concentrated
juice prior to the freezing process. This is seen in step 12 in the flowsheet above. The
students must also add fresh juice to their concentrate in order to control the quality of the
final product. Activity 5 will lead the students through determining how much fresh juice
they want to add to their process in order to produce the taste quality that they desire for
their product. As will become evident in Activity 5, there is a cost associated with both
the addition of fresh juice and the percent concentration of the juice in the students’
process design. (See Cost section below.)
Cost
The continuing costs involved in the production of orange juice can be simplified into the
following categories:
• raw materials (oranges, water, packaging containers)
• energy (heat to evaporate, a means of cooling, electricity to operate
equipment, and general utilities for the facilities)
• labor (people’s salaries and benefits)
• shipping (transportation from manufacturing site to customer)
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Table 1: Cost Analysis Data
Energy
0.0008
Labor
0.00002
Raw Materials
0.00002
Shipping: truck
0.17196
Shipping: train
0.15873
Shipping: boat
0.14551
Shipping: plane
0.66139
cents/minute
processing time
cents/minute
processing time
cents/mL
fresh juice
cents/gm
final product
cents/gm
final product
cents/gm
final product
cents/gm
final product
Other types of costs would be the capital investment to build the facility, the repair and
maintenance of equipment, quality and standards monitoring, and taxes. For this project,
the students will consider the cost of raw materials, energy, labor (employee salaries and
benefits), and shipping. Table 1 below gives rates for each of these items. Shipping costs
are based on 2003 values (See Activity 1.), and other costs are set to show relative impact
on the cost of the students’ product.
An extension project involves using an Excel spreadsheet to determine which of these
cost factors most strongly impacts the final cost of the orange juice for Boston Public
Schools. Through this extension, students see that the shipping cost has the most impact
on the cost per 8-ounce glass, and therefore the more concentrated they make their juice,
the more economical their process. However, they must balance this economic gain by
the quality of the taste of the reconstituted juice. (See Taste Quality section above.)
A good engineer designs processes while considering the cost impacts of his or her
design. For example, since raw materials cost money, the water that is collected from the
evaporation process can be recycled and used to wash off the fresh fruit.
101
Safety
Some engineers spend their whole jobs evaluating the safety of processes and designing
ways to both protect the workers and economically produce the product. Factors that
impact safety are:
• Temperature: Evaporation requires a lot of heat. Process equipment gets
hot, and the hot steam leaving the orange juice must be contained and
handled safely.
• Ergonomics: Any time that workers interact with materials or products,
they must be able to do so without injuring their bodies. For example,
valves must be within reach, and workers should be able to sit while
sorting oranges.
• Personal protective equipment: Employees must wear safety glasses,
gloves, and steel-toed shoes.
Engineers need to specify when insulation needs to be placed on equipment to prevent
workers from burning themselves. During the design process, a good engineer will
consider the safety of raw materials used in the process and choose the safest alternatives.
Environment
Some engineers spend their whole jobs evaluating the environmental impact of processes
and designing ways to both protect the environment and economically produce the
product. Environmental considerations include:
• treating and disposing of waste water
• capturing and treating air pollutants
• monitoring the quality of any liquid or gas emissions (like stacks or
wastewater)
For example, condensing the evaporated water will safely remove the steam from the
environment and the condensed water may then be recycled to other parts of the process
to save on the cost of water.
A good engineer will consider the impact of his or her design on the environment. For
example, pesticides used in the orange groves may contaminate the water used to wash
the fresh oranges. Therefore, an engineer will put in water collection tanks under the
wash tables, so that the water can be decontaminated.
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Materials
For flowsheets
• large paper
• colored markers
• worksheet
For prototype
• hot plate
• duct tape
• stainless steel measuring cup
• plastic bags
• funnel
• straws
• ice
• collecting cup
• thermometer
For condensation demonstration
• hot plate
• glass plate
• ice
• plastic bag
1. Read through background.
2. Set up condensation demonstration in front of class.
3. Show the three heating methods to remind the students what they did in Activity 2.
4. Supply materials. Each group should be supplied with paper and markers to draw
their flowsheet and write their procedure. Display one set of prototype materials for
each group, so that they know what is available.
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Doing the Activity
1. Class Discussion
Challenge: Provide low-cost, good-tasting orange juice to kindergarten breakfast
programs in Boston.
What we have learned:
Activity 1: Concentrate the orange juice in order to economically ship to Boston.
Activity 2: The three methods of heat transfer (conduction by hot plate, convection
by hair dryer, and radiation by heat lamp) produce different time versus
temperature curves. The hot plate is most efficient.
Activity 3: Flowsheets are used by engineers to communicate ideas about
processes.
We have identified the problem (need to concentrate the orange juice in order to meet
cost challenge), and we have researched the problem (from types of orange juice, to
heating methods, to learning how to communicate our design ideas through flowsheets).
Next steps: Design some possible solutions, choose the best solution, and create a
flowsheet and procedure for our best solutions. We are on steps 3 and 4 of the design
process.
In Activity 2, we used different heat transfer techniques to evaporate some of the water
out of the fresh orange juice in order to concentrate the orange juice to reduce its shipping
weight and hence its cost to the Boston Public Schools. In Activity 3, we reviewed a
flowsheet of the Tropicana concentrated orange juice manufacturing process, and we
pointed out the evaporator – the piece of equipment that provides heat and concentrates
the orange juice. What do you think are some differences between the evaporation
processes you tested in Activity 2 and the manufacturing process at a manufacturing
orange juice concentration plant?
•
•
Size: 200 mL of fresh juice (mini process) vs. 2 million liters of fresh
juice (orange juice manufacturing process)
Other process steps and tools: orange sorting, squeezing, freezing, and
canning.
Things to think about when designing the process: The goals of the process are to
• produce concentrated orange juice
• make sure the orange juice tastes good
• make the product cost affordable
• make the product safely – not hurt any workers
• make the product without damaging the environment
104
When engineers design a process, they have to consider not only the science, but also the
quality of the product, the final cost of the product, and the impact of the process on both
the environment (air, water, and soil) and worker safety. Now it is your turn to be an
engineer. You are going to design a prototype process, a small-scale process that can be
tested before a large-scale process is designed and built.
From your observations as a scientist, you have observed different rates of heating and
maximum temperatures reached by the three different tools for heat transfer. Consider
which observations from the science experiment you should consider.
The maximum temperature you observed is related to the feasibility of the process. In
order for the science of evaporation to work, you have to heat the orange juice enough to
evaporate water. Therefore, your process must reach at least 100ºC.
2. Group Work
Using your scientific observations and looking at the materials supplied, design a heating
process on paper using symbols that show your choice of a heat source and the tools you
will use in the heating part of the process. Begin building your prototype so that it reflects
your flowsheet.
Stainless
Steel Pot
OJ
Heat
Source
Figure 1: What this may look like
3. Class Discussion and Condensation Demonstration:
From your observations, what happens when you heat the orange juice?
• evaporation of water, volume decreases
• orange juice and beaker get hot
• taste changes
In a large scale process, there is a lot of water generated, about 100,000 – 400,000 gallons
per day at a typical manufacturing rate.
Considering our goals (quality, cost, environmental protection, and safety of workers),
which ones are impacted by this volume of water and what do you think engineers do to
manage the water generated?
105
•
•
•
water impacts cost (treatment costs, waste disposal cost): recycling water
for washing oranges is one solution
water impacts environment
water could impact safety due to hot steam: condensing for both safety and
reuse of energy and water
Some engineers spend their whole jobs evaluating the environmental impact of processes
and designing ways to both protect the environment and economically produce the
product.
Demonstrate Condensation: Boil water and condense on a glass surface chilled with ice
in a plastic bag.
Show students the tools used for collecting condensation: straws, funnel, duct tape, ice,
plastic bags, and collecting jar.
4. Group Work:
Go back to your flowsheets and design a way of managing your water generation with the
materials provided. Continue building your prototype.
Pipes
Co
n
Funnel
de
ns
er
Stainless
Steel Pot
OJ
Collecting
Jar
Heat
Source
Figure 2: Possible Flowsheet
At this point, further steps could be added to the flow sheet including cooling the orange
juice concentrate, adding fresh orange juice, adding water, and tasting.
106
5. Class Discussion:
We have observed that our equipment (the beaker) gets hot as we heat the orange juice.
Considering our goals (quality, cost, environmental protection, safety of workers), which
ones are impacted by heat, and what do you think engineers do to manage the heat?
• insulation to protect workers
• make hot processes automated to minimize worker involvement
Other safety issues in a manufacturing process include machines and repetitive tasks and
their effects on back strain or muscle injury. Some engineers spend all their time making
sure processes are safe for the workers.
6. Group Work:
Update your flowsheet to show safety as part of your design. Add safety features to your
prototype.
Pipes
Co
Insulation
Funnel
nd
en
s
er
Stainless
Steel Pot
OJ
Collecting
Jar
Heat
Source
Figure 3: Possible Flowsheet
107
7. Class Discussion
Now that we have the equipment (tools) for this part of our process, we need a procedure.
The procedure of a process is how the equipment is used. It is often called an operating
procedure because it tells the workers how to operate the equipment in order to produce a
product that is of high quality and affordable cost. It can often be a list of steps and
important process conditions (called process variables) like temperature and the time for
each step. The first step of our process is heating the orange juice, and we have designed
the equipment to do this. Now we need to know the amount of time we want the orange
juice to be heated and the process conditions that we want to observe.
In our science experiment, what process variables did we monitor?
• temperature
• time
• volume
How are these process variables linked to our process goals?
• Cost: The temperature affects the evaporation rate. The lower the
temperature, the longer it will take to evaporate the liquid.
• Taste: The volume of water that is removed impacts the taste of the
concentrate.
List on your flowsheet the variables that are important to your operating procedure.
• volume change
• time
• temperature
In Activity 5 you will determine the exact process conditions for your concentration
process.
108
STUDENT WORKSHEET
Design a Heating Process
Materials
• large paper
• colored markers
• hot plate
• duct tape
• plastic bags
• funnel
• straws
• ice
• collecting cup
• thermometer
Procedure:
1. Design a heating process on paper using symbols that show your choice of a heat
source and the tools you will use in the heating part of the process.
2. Design a way of managing the water generated from heating the orange juice.
3. Update your flowsheet to show safety as part of your design.
4. List on your flowsheet the variables that are important to your operating
procedure.
Condensation: the process where matter changes from vapor to liquid
Evaporation: the process where matter changes from liquid to gas
109
STUDENT WORKSHEET
Name _________________________
Orange Juice Activity #4: Prototype Design
Date ___________________
Now that you have some experience with flowsheets, procedures, and the heating of
orange juice to produce concentrated orange juice, you are ready to start designing your
orange juice concentration process. Remember that your challenge as a Tropicana
Engineer is to supply good-tasting orange juice to the Boston Public Schools for the cost
of 15 cents for an 8-ounce glass.
Answer Questions 1 and 2 before beginning your prototype design.
1. Name at least 5 goals of your process.
2. Based on what you know about the orange juice concentration process and your
observations from the heat transfer experiments, what ideas from science must
you consider in engineering a prototype for your orange concentration process?
Answer Questions 3 through 7 after designing your prototype.
3. How do you address safety and environmental concerns in your prototype?
4. What process variables do you need to specify to operate your process?
5. How does each process variable impact the cost and quality of your product?
6. What information do you need in order to specify your process variables?
7. How can you find this needed information?
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Extensions
1. Use a spreadsheet of costs to determine which processing parameters most impact the
cost of an 8-ounce glass of orange juice. Discuss how this knowledge will help you
design a process to meet your goal. The spreadsheet is available on the STEM Team
website: www.stemteams.org.
2. Alternative or additional materials include: coffee cans, aluminum pans, and tubing.
See the STEM Team website (www.stemteams.org) for additional ideas.
3. Students may wish to present their plans and discuss alternatives in the classroom.
4. As an alternate approach to reduce class time required for Activities 4, 5, and 6, the
goals of all three can be somewhat condensed and converted into one activity. This
alternative is presented at the end of Activity 6.
5. The scope of the process development can be extended to include the addition of fresh
orange juice after the condensation and cooling step in order to improve taste. (As
written, this is done manually by the students after running their process in Activity 6.)
References
1. www.ultimatecitrus.com/pdf/fcoj.pdf
2. Science Explorer: Physical Science. Upper Saddle River, NJ: Prentice Hall, 2002. 67.
3. Esler, William K. and Mary. Teaching Elementary Science: A Full Spectrum Science
Instruction Approach. Belmont, CA: Wadsworth Group, 2001. 320.
4. www.tropicana.com/index.asp?ID=60
5. members.aol.com/citrusweb/oj_story.html
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Part 5: Orange Concentration Flowsheet and Prototype II
Learning Strand:
Engineering Design
Concepts:
Symbols
Planning on Paper/Building a Prototype
Preparation Time:
60 minutes
Activity Time:
90 minutes
(30 minutes for taste testing and 60 minutes for
determining heating conditions)
3
Group Size:
Group of 4 – 5 students
Purpose
The purpose of this activity is to have students determine how heating time impacts
volume change, cost, and taste. Students need this information to determine how long
they will run their orange juice concentration process and how much fresh orange juice to
add at the end to get the necessary taste quality. At this point students know how they are
going to heat their orange juice, but before they can test their prototype, they must
complete the flowsheet by determining the process variables of heating time and amount
of fresh juice to add. In order to determine these process variables, they need to go back
to the laboratory and experiment with how much the volume changes with time and how
much fresh juice to add to make it taste good. They also need to project the cost of their
process to see if it meets the challenge amount of $0.25 per 8-ounce glass. (As an
extension, measuring the amount of vitamin C can be added to the problem constraints in
this activity. See Extensions section.)
In “Orange Concentration Flowsheet and Prototype II,” students will:
1. Experimentally determine the amount of fresh juice to add to different
concentrations of orange juice to meet the taste quality requirement;
2. Estimate the cost of an 8-ounce glass of juice produced by their process;
3. Finalize their flowsheets and prototype with this new science information; and
4. Present their flowsheet and prototype to the class (optional).
112
Outcomes
By the end of this activity, students will be able to show a complete flowsheet, procedure,
and prototype for their process.
Other skills practiced in this activity include mathematical analysis, analytical thinking,
and effective communication.
Connections and Overview
CONNECTIONS TO “THE GREAT ORANGE SQUEEZE”: At this point, students
understand the shipping weight-to-cost relationship from Activity 1 and have decided that
juice to Kindergarten Breakfast Programs in the City of Boston. They have played the
role of scientist to discover characteristics of the three forms of heat transfer (conduction,
convection, and radiation) and have observed the heating of orange juice (Activity 2).
They have learned about processes, flowsheets, and procedures (Activity 3). They have
also constructed a preliminary flowsheet and prototype for their best solution (Activity
4). They now need to finish their procedure by determining their process variables. This
activity leads into Activity 6 where they will finish and test their prototype and begin
redesigning their process.
(Develop possible solutions), 4 (Select best possible solution), 5 (Construct a prototype),
6 (Test and evaluate), and 7 (Communicate solution) are illustrated and practiced in this
activity. Students must “go back to science” to discover the relationships between time
and volume and time and taste when heating the orange juice to remove water. This
reinforces the message that science and engineering are different and interrelated careers.
OVERVIEW OF THIS ACTIVITY: In “Orange Juice Concentration Flowsheet and
Prototype II,” students will determine the setting to be used on the hotplate, the amount
of time that they will heat their orange juice, the volume of water they expect to remove,
and the amount of fresh juice they need to add to enhance the taste of their product. They
will then incorporate this information into their process flowsheet and procedure. They
may also test the vitamin C content of their juice at different points in their procedure
(See Extensions section.)
What is the prototype design missing?
• Temperature setting on the hotplate
• Time to concentrate which is directly related to the volume evaporated
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•
•
Volume of fresh orange juice added for taste
Projected cost of the orange juice
The temperature setting will affect the rate at which the water is evaporated from the
juice. The higher the temperature setting, the shorter the time it will take to concentrate
the juice. The time is needed to determine how long the process should run. Since orange
juice is made up of water and soluble solids, the water can be removed by boiling the
juice. (The boiling point of water is 100°C or 212°F.) The negative side to this method of
separation is that some of the soluble solids are heat sensitive and degrade. This has the
effect of changing the flavor of the juice. In order to combat the loss of flavor, small
amounts of fresh juice are added to the concentrate. Engineers and scientists work
together to determine how much fresh juice needs to be added to the concentrate for
maximum consumer appeal.
In the real manufacturing process, three times the volume of concentrated juice is added
as water to reconstitute the juice. So if the students begin with 200 mL of fresh juice, the
final juice concentrate volume plus fresh juice should be approximately 50 mL. The juice
sugars and solids concentration of fresh juice is 12%. The sugars and solids concentration
is 65% for concentrate before fresh juice is added, and 42% by volume for concentrate
after fresh juice is added.
In this activity, students will track the time versus volume of the remaining orange juice
in order to determine the desired heating time for their process. They will then taste the
reconstituted juice for various amounts of fresh orange juice added to determine the
amount of fresh orange juice to mix with the concentrate from their process to produce
the quality of taste that they desire.
The cost impact can either be developed by the students with worksheets by hand or by
using Excel, or this can be done through a lecture with the teacher using Excel to show
students the projected cost of their design. It is valuable for students to see the cost
impact of design as one of the considerations of engineering. An example Excel
spreadsheet is available on the STEM Team website: www.stemteams.org.
114
Materials
•
•
•
•
•
•
•
•
•
•
hot plate
stainless steel measuring cup
timer
thermometer
fresh orange juice
water
sample cups (should hold 150 mL at a minimum)
pipettes
flowsheet and procedure from Activity 4
metal rulers
1. Read through background.
2. It is recommended that each group be split into two sub-groups so that the taste
testing and the concentrating can be happening at the same time.
3. Prepare multiple samples of four different concentrations of orange juice.
Students will use these samples to determine approximately how much fresh juice
should be added to their final product. Samples should have 25%, 50%, 75%, and
90% of the original volume removed.
4. To get a desired concentration, pour a certain amount of fresh orange juice into a
pot on stove and heat until it boils down to 100 mL.
Percent
Concentrated
Fresh OJ
Final Volume
25%
133 mL (about ½ cup)
100 mL
50%
200 mL (about ¾ cup)
100 mL
75%
400 mL (1 ½ cups)
100 mL
90%
1000 mL (4 ⅓ cups)
100 mL
1 cup = 8 ounces = 240 mL
Formula
Y = X / (1-Z)
X = mL of concentrate desired (at least 10 mL per group)
Y = volume of fresh juice to add
Z = % concentrate (0.25, 0.50, 0.75, 0.90)
115
Each taster in the group will need 10 mL of each concentrate per taste. The number of
options students are allowed to experiment with (and the number of tasters per group)
will determine the amount of concentrate needed for the class. The worksheets are set
up for four different combinations for each of the four concentrates. It is
recommended to have two tasters per group. Following this model, each group needs
80 mL of each concentrate so that they can add varying amounts of fresh juice to find
the best tasting combination. An Excel spreadsheet is available on the STEM Team
website (www.stemteams.org) and an example is shown below.
A Tropicana fresh orange juice carton contains 64 oz (or 1920 mL). Therefore, for a
class of 35 with 5 member groups and 2 people tasting per group, 4 combinations can
be made for each concentration. Five cartons of fresh juice are needed to produce all
the concentrate needed for Activity 5. The Excel spreadsheet can calculate the
amount needed for your class.
Class Size
35
Number of students
tasting per group
2
Number of combinations
allowed
4
Number of groups
7
concentrate needed*
560
mL 25%
560
mL 50%
560
mL 75%
560
mL 90%
* based on 10 mL per taste per person
Z
% final
concentrate
%
25%
50%
75%
90%
X
Y
input mL of
amount of fresh juice to heat to produce XmL
concentrate needed of Z concentrate
mL
~cups
mL
~cups
560
560
560
560
2 1/3
2 1/3
2 1/3
2 1/3
Total:
747
1120
2240
5600
9707
3 1/9
4 2/3
9 1/3
23 1/3
40.44
number of 64 oz containers needed:
5.1
116
NOTE: The students should start with 10 mL of the concentrate and add various
combinations of water and fresh juice to determine taste quality. The total volume of
water and fresh juice must add up to the correct volume for reconstituting the specific
concentrate. For example:
Percent volume removed
25%
50%
75%
90%
Amount of liquid to add
to 10 mL concentrate to
reconstitute
3 mL
10 mL
30 mL
90 mL
Thus, an example worksheet for 50% concentrate would look like:
Percent
Volume
Removed
50%
50%
50%
50%
Amount of
liquid to add to
10 mL
concentrate to
reconstitute
10 mL
10 mL
10 mL
10 mL
Amount of
fresh orange
juice added
Amount of water
added
0 mL
4 mL
7 mL
10 mL
10 mL
6 mL
3 mL
0 mL
Taste
5. Each group should be supplied with their flowsheet and procedure from Activity 4.
They also need materials to make measurements for heating, concentrating, and
adding fresh juice to their concentrated product. A worksheet for the data to be
collected is also recommended.
6. If students are to develop the economics of the process from unit conversion analysis
(see background), a lecture or class time may be needed. Alternatively, students can
fill out a worksheet after the laboratory activities or use Excel either individually or as
a class to see the economic impact of the different designs.
117
Doing the Activity
Begin the experiment by allowing students to taste test the concentrates. They will need
four 50 mL samples of concentrated orange juice, 50 mL of fresh juice, and 100 mL of
water. They will need a worksheet on which to record their results. Their results should
include the percentage concentrate; the volumes of concentrate, fresh juice, and water;
and the taste results.
Co-currently (or sequentially), students need to determine the settings (temperature
setting, time, and volume loss) for achieving that concentrate. Then using their current
flowsheet design, the next steps and procedure can be completed.
PROCEDURE
Pipes
Co
Insulation
nd
en
Funnel
se
r
Stainless
Steel Pot
•
Add 200 ml OJ to SS
Pot.
•
Turn on Heater to
setting 6.
•
Run system for 35
minutes for 30 ml of
concentrate and add
20 ml of fresh juice.
OJ
Collecting
Jar
Heat
Source
Figure 4: Example Flowsheet with Procedures and Settings
Cost Comparisons
Fresh OJ at start (mL)
Processing time (min.)
Fresh juice added (mL)
Volume final product (mL)
Cost per 8 oz glass
reconstituted (cents)
200
200
200
200
200
200
35
10
110
45
10
85
45
25
100
35
25
125
15
0
160
35
10
110
22.412
118
17.337 20.389 25.464 32.563
22.412
Procedure
Materials:
• hot plate
• timer
• thermometer
• fresh orange juice
• water
• orange juice concentrates
• sampling cups
• pipettes
• Flowsheet and Procedure from Activity 4
Procedure:
Note: Procedures A and B may be done simultaneously to keep all group members
occupied during the heating time.
A. Determining the Amount of Fresh Juice:
1. Take 16 sampling cups and label four cups with 25%, four with 50%, four with
75%, and four with 90% concentrate.
2. Measure out 10 mL volumes of each concentration into each labeled sampling
cup.
3. Beginning with the 25% concentrate, determine how much liquid you need to add
to reconstitute the juice. Enter that information into the data table.
4. Of the total volume, choose four different volume combinations of fresh juice
plus water that add up to that total volume and enter that information into the data
table.
5. Add those volumes to each cup, then taste. Record your taste results. Pass this on
to your other teammates.
B. Determining the Time, Volume, and Temperature Conditions:
1. Set up the hotplate and place the stainless steel measuring cup with 200 mL of
juice on top of the heating element.
2. Choose a temperature setting. Record this on the data sheet.
3. Based on your taste testing, you know the final concentration you are trying to
reach. (If you have not heard from the tasters yet, go ahead and get started. They
will let you know when to stop concentrating.) Determine how much volume you
need to remove to reach that concentration.
4. Measure the diameter of the measuring cup and record this value on your data
sheet. You will need this number to calculate the volume of the orange juice in the
measuring cup at each time interval.
119
5. Measure the height of the orange juice in the measuring cup and record it in the
first line (the START condition) in your data table.
6. Calculate the starting volume of orange juice and record it in your data table.
Note: This volume should be close to 200 cm3. (Why?)
7. Turn your hot plate to the desired setting and start the timer. Carefully and slowly
stir the orange juice as it is heating.
8. Measure the temperature at five-minute intervals and measure the height of the
liquid in the measuring cup at each time. Record results on the data sheet. Be
careful since the liquid will be VERY HOT!
9. Stop the experiment when the volume reaches the amount desired, or you run out
of time.
C. Determining Process Variables and Cost and Updating the Flowsheet:
1. Use the worksheet to project the cost of an 8-ounce glass of orange juice made by
your process.
2. Based on your cost, concentration time, and taste results, decide as a group what
your process variables are going to be (hot plate setting, time of heating, amount
of fresh juice added to concentrate).
3. Modify your flowsheet from Activity 4 to show this new information. Your
flowsheet for the prototype should now be complete.
120
STUDENT WORKSHEET
Name _________________________
OJ Activity #5: Taste Test for Fresh Juice Added
Percent volume
removed
Amount of
liquid to add to
10 mL
concentrate to
reconstitute
Amount of
fresh orange
juice added
25%
25%
25%
25%
50%
50%
50%
50%
75%
75%
75%
75%
90%
90%
90%
90%
121
Date ___________________
Amount of water
added
Taste
STUDENT WORKSHEET
Name _________________________
OJ Activity #5: Laboratory Data
Date ___________________
Data to collect during laboratory:
cm
Diameter of measuring cup:
Heating Time
Height of Orange
(min.)
Juice
(cm)
0
Start:
Hot plate setting: ____________
Volume of Orange
Percent Volume
Juice
Removed
(cm3)
(%)
Start:
0
Example Calculations:
Volume of Orange Juice (V):
V = (measured height)(3.14)(diameter of measuring cup/2)2
Percent Volume Removed (%):
% = (starting volume – V)/(starting volume)
Observations During Heating:
My process will heat for ___________ minutes, and I will add __________________ mL
of fresh juice after concentrating.
122
STUDENT WORKSHEET
Cost Worksheet
Energy
cents/minute processing time
0.0008
Labor
cents/minute processing time
0.00002
Raw Materials
cents/mL fresh juice
0.00002
Shipping
cents/gm final product
0.17196
0.15873
0.14551
0.66139
truck
train
boat
plane
mL of fresh OJ (starting)
minutes processing time
mL of fresh juice added
volume final product (mL)
gm final concentrated product
density of final concentrated product
(gm/mL)
use a density of 1 gm/mL if mass of final concentrated product is not measured
The cost for a product includes the cost of raw materials, energy to operate the
process, labor to operate the process, and cost to ship the product.
raw materials
(mL fresh OJ start + mL fresh OJ
added)(cents/mL)
Energy
(minutes processed)(cents/processing time)
Labor
(minutes processed)(cents/processing time)
123
Shipping
(gm final concentrated produced)(cents/gm)
Total cost for gms produced (sum of all parts)
Cost per gm (Total/gm produced)
Percent concentrated
(Ending volume)/(Starting Volume)
Density of concentrate (from above)
gm per 8 oz glass reconstituted
(8 oz)(% concentrated)(29.57 mL/oz)(density of
concentrate gm/mL)
Cost per 8 oz glass reconstituted
(cost per gm)(gm per 8 oz glass)
124
References
1. http://www.ultimatecitrus.com/pdf/fcoj.pdf
members.aol.com/citrusweb/oj_story.html
Extensions
1. Cost Analysis to Guide Design
Prior to performing the laboratory activity, use an Excel spreadsheet to perform the cost
analysis and change each process variable one at a time to determine the impact each
variable has on the cost of an 8-ounce glass of orange juice. Use this information to help
determine the process variables you hope to achieve with your design. An example Excel
spreadsheet is available on the STEM Team website: www.stemteams.org.
2. Testing for Vitamin C
A simple iodine test can be used to compare the vitamin C content of the various juice
concentrates. The number of iodine drops added to the solution up to the point that it
permanently changes color is proportional to the amount of vitamin C in the juice. That
is, the more drops of iodine you add before the color change, the higher the vitamin C
content of the concentrated juice. Students can use this as a quality control measure along
with taste to determine how much fresh juice to add to their concentrate from their
process. Another fun activity is to compare the amount of vitamin C in various types of
store-bought juices or other fruity drinks.
You will need the following materials for each student:
Orange juices or various juice drinks
a pipette for starch addition
a pipette for iodine addition
a plastic cup for each beverage
iodine solution
starch solution (consisting of one part baking soda to five parts water)
plastic spoons or stirring rods
Procedure:
1. Pour each beverage into a separate plastic cup (about 1/3 full or about 1 ounce).
2. With a pipette, add 10 drops of the starch solution to each cup. Stir thoroughly.
3. Begin adding the iodine to one of the cups of juice, one pipette drop at a time. Stir the
solution after each drop. Count the drops as you add them.
4. Keep adding, stirring, and counting drops until the juice turns a dark color. If the juice
turns color initially but then returns to its original color while stirring, continue to add
iodine drops.
125
5. Record the number of drops needed for the juice to permanently change color.
6. Repeat the above procedure for each juice you are testing.
126
112
Part 6: Orange Juice Concentration Process: Test and Retest
Learning Strand:
Engineering Design
Concepts:
Symbols
Procedures
Planning on Paper and Building a Prototype
Preparation Time:
60 minutes
Activity Time:
60 minutes
3
Group Size:
Group of 4 to 5 students
Purpose
The purpose of this activity is to have students test their process solutions, evaluate their
product in terms of cost and quality, and suggest a redesign strategy. In “Orange Juice
Concentration Process: Test and Retest,” students will
1.
2.
3.
4.
Demonstrate their process in the laboratory;
Evaluate their product’s ability to meet the challenge;
Present their solution to the class using their flowsheet; and
Recommend improvements to their process design.
Outcomes
1. Relate the Orange Juice project to all eight engineering design steps;
2. Effectively communicate an engineering design with a flowsheet and
procedure; and
3. Discuss the differences and interdependencies of science and engineering.
Other skills practiced in this activity include analytical thinking and effective
communication.
127
Connections and Overview
CONNECTIONS TO “THE GREAT ORANGE SQUEEZE”: At this point, students
understand the shipping weight-to-cost relationship from Activity 1 and have decided that
juice to kindergarten breakfast programs in Boston. They have played the role of scientist
to discover characteristics of the three forms of heat transfer (conduction, convection, and
radiation) and have observed the heating of orange juice (Activity 2). They have learned
about processes, flowsheets, and procedures (Activity 3). They have also constructed a
preliminary flowsheet and prototype for their best solution (Activity 4). They have
finished their procedure by determining their process variables (Activity 5). This activity
concludes the module, and in this activity the students must finish and test their prototype
and begin redesigning their process.
(Test and evaluate), 7 (Communicate the solution), and 8 (Redesign) are illustrated and
practiced in this activity. Students must build and test their prototype and evaluate its
performance and suggest ways to improve the process.
OVERVIEW OF THIS ACTIVITY: In “Orange Juice Concentration Process: Test
and Retest,” students will build and test their prototype based on their flowsheet and
procedure. After testing, they should evaluate their design and suggest ways to improve it
or what to do next in the process.
At this point students should build and run their prototype process exactly as they have
specified in their flowsheet and procedure. Designs will vary in terms of the time of
heating, the amount of fresh orange juice added, and the amount of initial volume
reduction (a function of the time of heating and the hotplate temperature). Students
should present their final design and the cost of their orange juice. They can have a
“Taste Off” of their final reconstituted orange juice so that the class can judge their
product.
The activity should be concluded by discussing the interaction between engineering
(using science to design processes) and science (finding out more information needed for
design) in creating a real solution to the problem.
128
Cost and Quality Analysis
The continuing costs involved in the production of orange juice can be simplified into the
following categories:
• raw materials (oranges, water, and packaging containers)
• energy (heat to evaporate, a means of cooling, electricity to operate
equipment, and general utilities for the facilities)
• labor (people’s salaries and benefits)
• shipping (from manufacturing site to customer)
Other types of costs are the capital investment to build the facility, the repair and
maintenance of equipment, quality and standards monitoring, and taxes. For this project,
the students will consider the cost of raw materials ($0.0000002 per starting mL of fresh
orange juice), energy ($0.000008 per minute of processing time), labor ($0.0000002 per
minute of processing time), and shipping ($0.0000146 per gram of concentrated product).
An extension project involves using an Excel spreadsheet to determine which of these
cost factors most strongly impacts the final cost of the orange juice for Boston Public
Schools. Through this extension activity, students will see that the shipping cost has the
most impact on the cost per 8-ounce glass of juice. Therefore, the more concentrated they
make their juice, the more economical their process. However, they must balance this
economic gain by the quality of the taste of the reconstituted juice. (See Taste Quality
section above.)
The heat used to evaporate water from the orange juice also causes a breakdown of
several chemicals in the orange juice. This impacts the taste of the reconstituted product.
In order to ensure a good-tasting reconstituted product for the customer, concentrated
orange juice manufacturers add a small amount of fresh orange juice to the concentrated
juice prior to the freezing process. This is seen in step 12 in the flowsheet above. The
students must also add fresh juice to their concentrate in order to control the quality of the
final product.
Materials
•
Flowsheet and Procedure as developed in Activities 4 and 5
Materials for prototype:
• hot plate
• duct tape
• plastic bags
• funnel
• straws
• ice
129
•
•
•
•
•
collecting cup
thermometer
measuring cup
orange juice
water
Make sure all materials are on hand and all flowsheets and procedures are finished.
Doing the Activity
Groups should work independently to complete and test their prototype. They should
build their prototype and then test to see if their procedure works. After completing their
test, they should evaluate their design and suggest any changes that they would make to
improve it. If it worked to their satisfaction, they should suggest what the next process
should be in producing concentrated orange juice.
Groups should present their processes, flowsheets, and procedures. They can calculate
the cost of their process for an 8-ounce glass of orange juice and see if the challenge
was met. They should also determine how close their actual process came to the
predicted costs determined in Activity 5. They should discuss their results and their redesign ideas. Finally the class can taste test each other’s product to determine which
tastes the best.
130
STUDENT WORKSHEET
Testing the Prototype
Materials:
•
•
•
•
•
•
•
•
•
•
•
•
•
flowsheet and procedure developed in Activities 4 and 5
hot plate
duct tape
stainless steel measuring cup
plastic bags
funnel
straws
ice
collecting cup
thermometer
measuring cup
orange juice
water
Procedure:
1. Build the prototype according to your flowsheet.
2. Test the prototype by following your written procedure.
3. Evaluate your design.
a. Did it perform as you expected it to?
b. What improvements would you make to the prototype?
c. What improvements would you make to the procedure?
d. If it worked to your satisfaction, what would the next step in the process
be to produce frozen concentrate?
131
By Erica Thrall, Ayala Galton,
Olga Nikolayeva, Jessica Louie, Diem Tran, and Anna Swan
Solar-Powered Chocolate Factory
Learning Strand:
Materials, tools, and machines
Engineering design
Concepts
Properties of materials (insulation,
reflection, absorption)
Solar energy
Electric circuits
Preparation Time (for teacher):
120 minutes
Activity Time:
585 minutes (thirteen 45-minute class periods)
Level of Difficulty: 3 (scale of 1 to 5, with 5 as most difficult)
Group Size: 2 students
Grade Level: 7 to 8
Cost: The cost of the activity is $160 per class of 25 students.
Purpose
The purpose of this activity is to reinforce the steps in the engineering design process;
give students experience in choosing appropriate materials and constructing prototypes;
and show how solar energy can be used for passive heating and the generation of
electricity. In “Solar Chocolate Factory,” the students will:
1.
2.
3.
4.
5.
develop a better understanding of solar energy;
research material properties (insulation, reflection, and absorption);
learn about convection, radiation, and conduction;
experiment with electric circuits; and
practice working as a team.
132
Outcomes
1. apply the engineering design process to solve a problem;
2. work as a team to choose materials and build a prototype;
3. explain how solar energy can be used for passive heating or generation of
electricity; and
4. demonstrate basic knowledge of electric circuits.
There are eight steps in the engineering design process:
1.
2.
3.
4.
5.
6.
7.
8.
identify the need or problem;
research the problem;
develop possible solution(s);
select the best possible solution;
construct a prototype;
test and evaluate;
communicate the solution(s); and
redesign.
In this activity, students will take part in six of the eight steps. They will research a
problem, develop possible solutions, select the best possible solution, construct a
prototype, test and evaluate the prototype, communicate the solution, and discuss how
they would redesign the prototype.
OVERVIEW OF THIS ACTIVITY: In “Solar Chocolate Factory” students learn about
solar energy, heat capacity, and heat transfer. The unit is framed as a bid the students
make to get a contract to improve the efficiency of a solar-powered chocolate factory by
also melting the chocolate after sunset. They use a 200-Watt bulb to model the sun and
design a “factory” that uses passive heating and heat storage to melt a chocolate chip. The
factory will heat up during a 5 minute “daytime” (lamps on), and the stored energy will
be used to melt chocolate during a 3 minute “nighttime” (lamps off). Students learn the
fundamentals of electric circuit theory and figure out how to put solar panels and
thermoelectric coolers together to cool melted chocolate into shapes of their own design.
133
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 9
Day 10
Day 11
Day 12
Day 13
Heat transfer demo
Lecture about heat and light
Design factory
Build factory
Data taking
Rebuilding and more data taking
More testing
Melt chocolate with factory
Introduction to electric circuits
Thermoelectric coolers
Testing with solar cells
Final testing
Guest speaker
Time required will vary depending on size of class and ability level of students.
In this activity there are three themes: the engineering design process, energy, and
electricity. This activity focuses mainly on energy. Students will learn about conservation
of energy; renewable energy sources, such as the sun; forms of energy, such as heat and
light; and how energy can be harnessed and used for work. Some basic electric circuit
theory will be introduced to help students use solar panels and thermoelectric coolers, and
the steps of the engineering design process will be reinforced.
What is Energy?
Conservation of Energy
Energy is the ability of a system to do work (i.e., move an object, drive turbines, power a
motor, etc.). Energy can be neither created nor destroyed. This fundamental law is called
conservation of energy. This might contradict everyday experience. For example, when a
cup of coffee cools, its heat energy seems to be lost. In fact, the energy has not been
destroyed; it has just left the cup and helped heat the room a small amount.
Types of Energy
There are many types of energy. Some examples are mechanical energy, electrical
energy, light energy, and heat energy. Mechanical energy is the energy of motion (kinetic
energy) or stored energy of position (potential energy). Electrical energy is energy
associated with net movement of electrons. Light energy is the kind of energy that travels
as visible radiation. Heat energy is the kinetic energy of atoms and molecules.
134
The potential energy in a water dam can be transformed to kinetic energy by opening the
gates to create a waterfall. Then the energy in the waterfall can be used to drive turbines.
In this way, potential energy is converted to kinetic energy, to mechanical energy, and
finally to electrical energy.
Like the potential energy in a dam, the electrical energy in a battery can be thought of in
terms of potential and kinetic energy. A battery has potential energy (voltage) that comes
from the separation of positive and negative charges. When the charges are allowed to
flow, the moving charges, or current, are in the form of kinetic energy. This can be used
for some purpose, such as to power a motor, heat the filament in a light bulb, or toast
bread.
Light and heat radiation energy are closely related. Both are electromagnetic waves.
Radiation from the sun includes ultraviolet (UV) light, visible light, and infrared light
(heat). Matter can absorb radiation and become hot. Heat energy in matter is related to
the kinetic energy of particles in the substance. The more the particles vibrate, the hotter
the object is.
Heat Transfer
Heat energy is the motion of molecules and travels by radiation, conduction, or
convection. Heat transfer through solids is called conduction, heat transfer through
moving gas or liquid is called convection, and heat transfer through space is called
radiation.
All three types of heat transfer can be demonstrated with a cup of tea. First, a cup of
water is heated in a microwave. A microwave oven heats water through radiation. In
radiation, energy travels as electromagnetic waves. These waves can travel through
empty space. In this way energy from the sun reaches Earth. The water molecules vibrate
with the waves, and the friction from the motion heats up the water.
When the cup of tea is removed from the microwave, heat is transferred from the tea to
the surrounding air through convection and radiation. In convection, heat travels by
actual flow of the warmed fluid (either a liquid or a gas). Convection causes warm air to
rise and cool air to fall.
If a metal spoon is placed in the tea, the spoon is heated through conduction. Heat travels
from the hot to the cold end of the spoon because the hotter molecules are moving with
greater speed. They bump into the cooler molecules and cause them to move faster. As
the fast molecules jostle the slow ones, heat moves up the spoon.1
Renewable vs. Nonrenewable Energy
Most energy used by people to heat their homes, power light bulbs, and perform other
tasks comes from fossil fuels like coal, oil, and natural gas. Fossil fuels were formed
hundreds of millions of years ago when trees and plants sank to the bottom of swamps
1
“Convection, Conduction, and Radiation.”
http://www.mansfieldct.org/schools/mms/staff/hand/convconrad.htm
135
and were covered by dirt and rocks. Over time, the water was squeezed out of the plants
and they turned into coal, oil, and natural gas. Fossil fuels are in limited supply, and as
the population grows and people around the world increase their standard of living, fossil
fuels are expected to become scarce. These are nonrenewable resources.
Some types of energy are not in limited supply; they are constantly being regenerated.
Examples include wind power, solar energy, biomass, and geothermal energy. Wind
power comes from convection from solar heat and air currents from the earth’s rotation.
Solar energy comes from the sun. Biomass stores energy from the sun in plants.
Geothermal energy comes from the earth’s core. (The term “renewable energy” is in
some way a misnomer since eventually the sun will burn out and the earth’s core will
cool down, but for practical purposes these energy sources will last forever.)
Solar Energy
The type of renewable energy modeled in this experiment is solar energy. The sun’s
surface is about 4700 degrees Celsius and radiates most energy in the visible range. In
this activity, a 200-watt bulb will be used instead of sunlight. The filament in the bulb is
only about 1000 degrees Celsius, so 80% of the energy from the bulb is radiated in the
near infrared instead of the visible part of the spectrum. Radiation passes through some
substances, is reflected by some, and is absorbed by others. Students should take
advantage of this fact when they design their solar houses. They want to allow energy to
enter their houses and then trap it inside.
Solar energy is free in a sense since no one owns sunlight, but collecting it can be
difficult and expensive. A lot of space is needed to collect enough energy to be useful.
Also, the amount of sunlight available depends on time of day, season, weather, and
geography. Presently, solar energy costs about five times as much as fossil fuels,2 but
with development of solar cell technology and economies of scale, solar energy could
become a more practical option.
A recent breakthrough has made it possible to produce flexible, plastic solar cells that use
the sun’s infrared rays. This new development might make solar cells five times more
efficient. The new plastic solar cells can be sprayed onto other materials. For instance, it
could be sprayed on a sweater and used to power a cell phone. Researchers have high
hopes for their new material. They want to make solar farms in deserts to provide enough
electricity for the entire planet.
Passive Heating
Solar energy can be used in several ways: for passive heating of buildings, for heating
water, and to generate electricity. To take advantage of passive heating, architects design
homes with materials that have a high heat capacity.3 For instance, stone walls have a
2
The price of oil does not take into account the geo-political cost of securing availability of foreign oil.
Specific heat capacity (Cv) is a measure of how much energy it takes to heat one unit mass of material one
degree. A material with high heat capacity can store a lot of energy. Water: Cv=4.18 kJ/kgK, Air: Cv=
1kJ/kgK, Brick Cv= 0.84 kJ/kgK (Note that 1 kg of air is a large volume, ~ 1 m3.)
3
136
high heat capacity and can absorb heat during the day and release it at night. In a cold
climate, one can make use of solar heating by using large windows on south-facing walls
and good insulation. To keep a house comfortably warm in winter and cool in summer,
the roof should be well insulated and reflective (light-colored). Insulation helps keep heat
in in the winter and heat out in the summer by slowing heat transfer. Tiny, closed air
spaces in the insulation limit conduction. Also, foil helps reflect heat.
Many swimming pools are heated by passive solar heating. Water is pumped through a
black plastic solar collector. The dark color helps absorb heat from the sun. The warm
water is pumped back into the pool. Similarly, a solar collector can be used to heat water
used in a house. A large, flat box with a black bottom and transparent top can be placed
on the roof of a house. Water runs through pipes in the box and is heated by the sun.
In designing a building that uses passive heating, or in designing a solar chocolate factory
as in this activity, understanding some basic material properties proves important. One
property to keep in mind is thermal conductivity, or the measurement of the speed at
which heat travels through a material, and another is the absorption and emission of
radiation. Sunlight passes through some substances, is reflected by others, and is
absorbed by the rest. A block coated with lampblack will absorb 97% of visible light,
while a silver-coated block will only absorb 10% and reflect the other 90%.4 Students can
take advantage of the ability of some materials to relect or absorb energy when they
design their houses.
Electricity Generation
In a more technical approach, solar energy can be used to generate electricity. One way
of producing electricity is through photovoltaics or solar cells. Solar cells produce
electricity directly from sunlight. Solar cells are used in calculators, on satellites, and on
roof-tops for home electricity use.
A solar cell is the opposite of a light emitting diode (LED). An LED emits light when
powered by a voltage; a solar cell creates a voltage when light is absorbed. When light
hits a solar cell, light is absorbed in a semiconductor pn junction. The “p” stands for
positive charge (“holes”), and the “n” stands for negative charge (electrons). A pn
junction has a built-in electric potential. When light is absorbed near the pn junction,
electrons are pulled in one direction and the remaining “holes” in the other direction. This
causes a voltage to be built up, which can be used to power a device. (To learn more
about solar cells, consult the Resources section at the end of this unit.)
The power from the sun that reaches the earth, is about 500W/m2. To increase efficiency
in harvesting solar energy, a concentrating solar power system is used. For example, a
parabolic trough (shaped like a cylinder cut in half the long way) uses the sun’s heat to
heat oil, and then the oil heats water, and the resulting steam produces electricity in a
steam generator.
4
sol.sci.uop.edu
137
Students might have played with a magnifying glass to focus the light to a small spot that
gets hot enough to light a fire. When using solar energy, the challenge is to find some
way to trap it, store it, and convert it. The advantages are that it is a renewable resource
and it does not contribute to air pollution or global warming.
What is an Electric Circuit?
The Basics
Some students may have experimenteded with electronics at home by building a radio or
taking apart a TV, but for most kids electric circuit theory will be brand new. Electric
circuit theory is a collection of simple and elegant rules that describe the flow of
electricity. Students will receive a brief introduction to electric circuit theory, so they can
use a solar cell as a battery to run a thermoelectric cooler to cool their melted chocolate.
The simplest electrical circuit consists of a power source (such as a battery), a conductor
(such as a wire) to carry electrical current, a load (such as a light bulb or motor), and
another conductor to close the circuit by carrying the electrical current from the load back
to the power source. Often there is a switch on one of the conductors which opens or
closes the circuit.
Electric Circuit Diagram
A circuit diagram is a drawing that shows how the circuit elements are arranged. In the
circuit diagram above we have a source, a load (the light bulb), and a switch. Once the
switch is closed, current will flow around the closed path.
Current is the flow of charged particles. The power source has two terminals with
opposite polarity. You are familiar with this from daily life. Batteries are marked with (+)
and (-). We think of current as flowing out the positive end and into the negative end. The
polarity matters when you jumpstart your car; you have to match the red jumper cable (+)
with the postive part of your battery and the black jumper cable (-) with the negative part
of your battery. For some devices, such as a light-bulb, it doesn’t matter which direction
the current flows.
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The Water Analogy
The difficulty in understanding electric circuit theory is that it is invisible. You can’t see
the tiny electric charges flowing through a wire. For that reason it is sometimes helpful to
think of current traveling through a wire like water flowing through a stream.
Think of a stream. Why does the water flow? It flows because of gravity. The water at the
top of a hill has potential energy. This potential energy is converted into kinetic energy as
the water flows downhill. Without the potential energy (i.e., without the height difference
from top to bottom) the water would not flow.
Now think of the circuit. The current is like the stream. The current cannot flow without
potential energy. In an electric circuit, the potential is called voltage. Without a voltage,
the current will not flow. The voltage source can be a battery, or in the case of this
activity, a solar panel. A power source is a stored energy difference.
Now, continuing with our water analogy, think of the rocks, pebbles, tree branches and
other obstacles that the stream runs over along its way. These provide resistance and slow
the water. In a similar way, in our circuit, we could add resistors to limit the electrical
current.
Water Analogy Diagram
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Maybe an enterprising individual along the bank of the stream notices all the water
rushing by and thinks, “Hey, I can harness some of that energy!” So this person builds a
water mill and uses the energy to grind wheat into flour. In our circuit, we use the current
rushing by and draw off a stream of electrons to power a load. A load is a device that uses
electrical energy to do work (for example, a light bulb or a thermoelectric cooler). Note
that when water is used to run a water mill or current is used to run a light bulb, the same
amount of water or current exists before and after the load (due to conservation of mass).
As a conclusion to our water analogy, we’re going to think of the word “current.” If a
stream has a strong current that means more water is flowing. With electricity, the current
is a measure of how many charges are rushing by per second.
Definitions
Term
Current
Voltage
Resistance
Power
Symbol Units Definition
I
Amps A measure of the flow of electrons in a wire
V
Volts The potential difference that makes electrons flow
through a wire
R
Ohms Caused by a load, converts energy in a circuit into
another form
P
Watts The rate at which energy is transferred
Ohm’s Law: V = I R
Current, voltage, and resistance are all related by Ohm’s Law. The voltage is equal to the
current times the resistance.
Power: P = V I
You can also calculate the power. Power equals the voltage times the current.
Parallel and Series Circuits
There are two basic ways to arrange circuit elements in relation to one another, in series
and in parallel.
Two elements in series are arranged so that current flows through one and then the other.
Two elements in parallel are arranged so that the current divides and flows through
different paths before coming together again.
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What is the Engineering Design Process?
This activity demonstrates the basic steps of the engineering design process. You can use
this opportunity to introduce the steps to your students, or, if they are already familiar
with them, to review them and discuss how they apply to this unit.
The first step is to identify a problem. In this activity, students will solve two problems
that have already been identified. They will build a factory that uses passive heating to
melt a chocolate chip and use a solar panel and thermoelectric cooler to cool the
chocolate. Students will first conduct research by testing different materials.
Then they will use the information they learned about the materials to design a factory
that will collect heat. Team members will work together on drawing their proposed
solution to the problem, constructing a prototype, and testing the prototype. Then they
will communicate their design with the rest of the class.
Steps in the Engineering Design Process
Throughout this activity the diagram on the next page will appear on student worksheets
to show how each step in the activity relates to the overall design process.
Step 1: Identify the Problem
Step 8: Redesign
Step 2: Research the Problem
Step 3: Develop
Possible Solutions
Step 7:
Communicate
the Solution
Step 6: Test/Evaluate Solution
Step 4: Select a Solution
Step 5: Construct a Prototype
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Materials
Note: Ordering information is provided below for the items marked with an asterisk.
Day 1: Introduction and Heat Transfer Demo
• Thermometer
• Hot plate or candle and matches
• Aluminum foil or copper metal strip
• Glass rod or wooden spoon
Days 3-7: Building and Testing the Factory
Per group of 2 students
• Copies of the worksheets for each student
• Ruler
• Pencil
• Scissors
• Masking tape
• Lamp with 200-watt light bulb
• Light stand
• Thermometer
• Watch with second hand or stopwatch
• Graph paper
Per class
• Cardboard (about 5 large boxes)
• Foam*
• Clear plastic (saran wrap, transparency, or report covers)
• Aluminum foil
• Construction paper
• Sand
• Metal block
Day 8: Melting Chocolate with the Factory
Have same materials available as on days 3-8.
• Chocolate chip
• Toothpick
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Day 9: Introduction to Electric Circuits
• Copies of the worksheets
• Breadboard
• Battery
• Lights
• Thermoelectric cooler
• Wires
Days 10-11: Designing the Cooling Circuit
• Copies of the worksheets for each student
• Two 2-V, 200-mA solar cells for half the groups and two 1-V, 400-mA solar cells for
the other groups*
• Breadboard*
• Thermoelectric cooler*
• Clear plastic tray
• 2 coffee mugs
• Piece of cardboard
• Piece of aluminum
• Lamp with 200-watt light bulb
• Light stand
• Ruler
• Melted chocolate chip
• Plastic strip thermometers*
Day 12: Competing for the Bid
Same materials as day 10 and Solar Chocolate Factory from day 8.
Day 13: Guest Speaker
Your guest speaker may need access to a laptop and projector.
Safety Concerns: This activity involves heat. Make sure that students keep an eye on
their factories during testing. They should immediately turn off the lamp if they see
materials melt or smoke. (Warn them to turn off the lamp before unplugging it to avoid
sparks!) They should keep the lamps at least the recommended distance from their
factories. Have a fire extinguisher on hand.
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1. A few weeks before the activity, order the thermoelectric coolers, solar panels,
breadboards, foam, and thermometers.
*Ordering Information
Item
Lamp
Light bulb
Foam
14" x 18" x 5/8" foam tray
LCD strip thermometer,
16 to 32 degrees Celsius
Mini solar cells
(2-V, 200-mA and 1-V,
400-mA, as explained
above)
Small breadboard, 830
total insertion points
Thermoelectric coolers
(TE-127-1.0-1.5, standard
thermoelectric modules)
Supplier
Contact Info
local hardware
store
Catering Supplies
Price
per
Item
$20.00
$3.00
(305) 443-0112
$0.68
Arbor Scientific
(800) 367-6695
$1.25
LEGO
(800) 362-4308
$4.46
(When you call, ask the customer
service person to label the cells
with correct voltage and current.)
Iguana Labs
(800) 297-1633
$4.50
TE Technology
Inc.
(231) 929-3966
$11.20
2. Contact an engineer who works with solar power or wind power and ask her to visit
your classroom. (You may also want to contact a nearby university and see if they
have a solar car team. One of the students could come and speak.)
3. Collect all the materials.
4. Read the background section for an introduction to energy and electric circuits. You
may also want to visit some of the websites suggested in the Resources section.
5. Plan groups of two students. Consider forming all-girl groups to give girls greater
confidence.
6. You may want to make copies of the background section and have your students read
it for homework.
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Doing the Activity
Day 1: Introduction and Heat Transfer Demo
Prepare
Set up the Heat Transfer Demo.
Introduction
Hand out the Overview worksheet and discuss it with students.
Heat Transfer Demo (about 20 minutes): Convection, Radiation and Conduction
You will demonstrate the three different ways heat can travel. Write convection,
radiation, and conduction on the board and explain.
1. Heat radiation is the emission of infrared waves that can travel through empty space.
(This is how the sun’s radiation reaches earth.)
2. Convection occurs in liquids and gases. When a gas gets hot it expands, gets lighter,
and rises up. (Think of a hot air balloon.) For example, when a candle is lit in space it
will not continue burning as it does on earth. On earth, thanks to gravity, the hot air
expands and rises as it gets less dense. Then cool air flows toward the candle and
carries new oxygen toward the wick. Combustion continues to take place. In space,
with no gravity, and thus no convection, the candle rapidly uses the oxygen in its
immediate vicinity and goes out.
3. Conduction happens when hot, mobile electrons collide with colder electrons and
transfer kinetic energy. In metal, the electrons are mobile, so metals conduct heat
much better than an insulating material like wood. The atoms in an insulating
material also conduct heat but much less efficiently.
Ask students to identify the primary heat transfer mechanism in the following examples:
1. You are cooking with a frying pan with a metal handle on an electric stove. You
notice that you need an oven mitt to hold the handle. How did it get hot? (Conduction.
Note that on a gas stove, the main reason will be convection.)
2. You are sitting in your swimsuit in the sun and are getting hot, so you move into a
cooler spot in the shade under an umbrella. How did the sun heat you? (Radiation.
The difference between the temperature in the sun and the shade gives the
contribution from radiation.)
3. At a candlelit dinner party, your attention wavers and you amuse yourself by holding
your finger above the flame. You notice that even well above the flame your finger
gets hot. What is the main heat transfer mechanism?
(Convection.)
4. In a coffee thermos (a thermos with the wall consisting of two layers of glass with a
vacuum in between), what is the main heat transfer mechanism?
(Radiation. Glass does not conduct heat well, and there is no convection since there is
no air.)
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Demo Procedure
Set up a hot plate (or a lit candle) in the front of the room and turn it on. Check the
temperature:
1. Above the heat source (convection, hot air rises);
2. To the side of the heat source (radiation);
3. To the side of the source, but connected via metal (mainly conduction with some
radiation).
Ask students to predict which area is hottest before you tell them the results. Ask them to
identify the primary heat transfer mechanism in each case. Use a thermometer and
measure the temperature 10 cm to the side of the hotplate and 10 cm above the hot plate.
Allow some time for the temperature to stabilize. Use a tightly folded ribbon of
aluminum foil or a copper strip and place it on the hotplate extending it 10 cm to the side.
The temperature difference between the side of the heat source and the end of the metal
strip will give the contribution from conduction. Try the same procedure with an
insulating material like a glass rod in place of the metal strip.
Day 2: Introduction to Energy
Lecture: Introduction to Energy
On the first day, draw upon the information in the background section to talk to your
students about energy, especially solar energy. Ask kids where they think the electricity
in their home comes from and what some of the problems are with our current
dependence on fossil fuels (i.e., global warming, pollution, unequal distribution of natural
resources, dependence on foreign oil).
The lecture should address these key topics:
1. Forms of energy
2. Energy conversion
3. Energy conservation
4. The power industry
5. Heat capacity
6. Heat transfer
7. Introduction to the design challenge
Let students know that in this unit they will be using a 200-watt incandescent bulb in
place of the sun. Highlight some differences between the sun and the bulb.
1. The bulb has a metal filament. Current passes through the filament, gets hot, and
makes it glow. The bulb will reach about 1000 degrees Celsius. 20% of the energy
produced by the light bulb is light and 80% is heat.
2. In contrast, the sun releases about 50% visible light, 25% UV light, and 25%
infrared radiation. The sun is about 5000 degrees Celsius at the surface.
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Day 3: Designing the Chocolate Factory
Lecture
Remind students that their goal is to let light/heat into the box and store it. Energy can be
absorbed, transmitted, or reflected from a material. Ask students to give examples that
illustrate each of these properties. (Smooth metal will reflect light (a mirror), glass will
transmit energy, and black material will absorb energy.)
Talk about insulation. By trapping air, fiberglass can slow both conduction and
convection.
Talk about heat capacity. Specific heat capacity is a measure of how much energy it takes
to heat one unit mass of material one degree. Different materials have different specific
heat capacities. Materials with low specific heats such as metals require less heat to raise
their temperature than do materials with high specific heats such as water.
Procedure
1. Hand out the “The Engineering Design Process” worksheets. Read the worksheet
instructions out loud while students read along. Explain the design challenge.
Ask them to fill in the box at the bottom of the worksheet.
2. Pass out the “Researching Different Materials” worksheet. Have students work
with their partners to answer the questions. Have them raise their hands when they
are done.
3. As students finish, hand them the “Building Your Test Site” worksheet. Have
students design their prototype and sketch it in the space provided. As students
finish, they should raise their hands so volunteers can discuss their designs with
them.
Days 4–7: Building and Testing
the Chocolate Factory
Preparation
Set up the materials on a table in a central location. Arrange the students’ desks so that
they can work in groups of two.
Starting on day five when students start testing, set up lab stations with lamps already in
place.
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Procedure
Students will build their factories according to their design.
When students are done building, review the safety concerns before students begin
testing. Emphasize that the lamp must be 30 cm above the height of their factory roof.
Also, they should pay attention. If their materials start smoking, they must turn off the
lamp immediately. (Note: You may find that at 30 cm, students have difficulty getting
their chips to melt. Our test classroom used a height of only 15 cm. At that height the
chocolate melts faster, but you have to be more careful about safety concerns. You may
want to experiment with the height before your class begins and decide what height is
appropriate for your class.)
You can let groups test their designs as they finish building, or you can set up more
structured testing and have everyone test at once. This approach works best for large
classrooms. If you only have enough lab stations for half the groups, you can have the
other half act as “quality control.” The quality control groups can be responsible for
making sure the testers do not cheat by moving the lamp closer or melting the chocolate
in their hands.
When testing, remind students that the goal is to have their factory retain heat. The
factory will heat up during a 5-minute “daytime” (lamps on). Then chocolate will be
added at night (lamps off) and melted by stored energy.
Students should record the temperature during testing to determine how well their factory
is working.
After testing, groups will want to redesign their factories. Have a class discussion about
whether their preliminary designs met their expectations and how they might like to
change them in the future.
Day 8: Melt Chocolate with Factory
1. Students follow directions on the “Testing Your Design” worksheet.
Preparation
Set up the lab stations with lamps for testing.
Procedure
Have students test as before. During the “daytime” walk around and hand each group a
chocolate chip on a toothpick. (The toothpick allows students to hold the chocolate
without melting it.) After five minutes, have the groups turn off the lamps and insert the
chips in their factories. Wait three minutes. Then walk around the room and see if the
chocolate melted successfully. You can poke it with a toothpick to check if it is melted.
Students should record the temperature throughout testing, as before.
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Day 9: Introduction to Electric Circuits
Prepare
Gather the materials for the electric circuits lab and demonstration.
Introduction to Electric Circuits (5–10 minutes)
Introduce the basic concepts of an electric circuit. (See background material.)
You can mention Ohm’s law, but it is not necessary for the lab.
Examples to Try in Class
1) Ohm’s Law
A 9 V battery and a bulb with a resistance of 4 Ω are connected in a circuit.
a) What is the power used in the circuit?
P = V*V/R = 9*9/4 = 81/4 = 20.25 W
b) What is the the current through the bulb?
V = R*I , I = V/R = 9/4 = 2.25 A
2) Voltage Sources in Series
a) Find the total voltage in the circuit at
right.
The voltage is added for voltage sources
in series. The total voltage source for this
circuit is Vtot = V1 + V2 + V3.
b) A flashlight with three AA 1.5 V batteries
in series has a total voltage of
Vtot = 1.5 V + 1.5 V + 1.5 V = 4.5 V.
c) What is the current?
The current through the circuit is
I = V/R = 4.5 V/2Ω = 2.25 A.
d) What is the power in the bulb?
The power in the bulb is
P = Vtot * Vtot/R=10.125 W.
3) Loads (Resistances) in Series
a) Find the total resistance in the circuit at
right.
Rtot = R1 + R2 + R3
I = V/Rtot
b) Example: A string of three lights are
wired in series with a 4.5 V battery. Each
bulb has a resistance of 2 Ω. What is the
total resistance?
Rtot = 2Ω + 2Ω + 2Ω = 6Ω.
c) What is the current through the circuit?
I = V/R = 4.5 V/6Ω = 0.75 A
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i
Source
(batteries)
+
+
+
-
Load
(light bulb)
V3
V2
V1
R=2Ω
Switch
“on”
“off”
Source
(battery)
+
-
i
Load
(string of light bulbs)
R1=2Ω
V1=4.5 V
R2=2Ω
R3=2Ω
Switch
“on”
“off”
d) What is the total power used by the circuit?
Ptot = P =Vtot*Vtot/Rto t= 4.5*4.5/6 = 3.37
W
e) How much power does each light use?
P = I*I*R = 0.75*0.75*2 = 1.125 W
Sources
V1
i1
itot=i1+i2
i2
V
2
4) Sources in Parallel
+
Imax
Imax
a) If the voltage source is limited in current,
we can get a higher current by putting the
Switch
sources in parallel so that the currents add.
V1 and V2 are current-limited sources.
“on”
V1 = V2 = 4V
“off”
Imax = 1.2 A
b) If we only had one source, what would the
maximum current be?
The maximum current would be 1A, which limits the voltage drop in the load (R =
2Ω) to V = I*R = 2.4V.
c) Find V, Imax, and Itot.
V= V1 =V2=4V
Imax=2.4 A
Then Itot=V/R= 4V/2Ω =2A, which works fine.
Demonstration and Hands-on Lab of Circuits (30 min.)
Use the student worksheets.
Day 10: Designing the Cooling Circuit
Lecture and Demonstration (10 min.)
• Explain how solar panels and thermoelectric coolers work. Make sure the students
understand that the solar panels will serve as batteries and the TE coolers are the
loads.
• Explain that a single solar cell is not powerful enough to drive the TE cooler and
that they will have to come up with a way to combine the solar cells to get more
power.
• Pass out the materials and ask students to sit near their partners.
• Show how the solar cells can be wired in series or parallel configuration. Go
through examples of what the limiting current and voltage is in each case.
• Attach a TE cooler to a 3 V (two AA batteries in series: 1.5V + 1.5V) to
demonstrate which side of the cooler is the cool side. Have students try this at
their desks as you do it in front of the class.
• Demonstrate how the strip thermometer works and how it can be used to check
how well the TE cooler is working.
• Discuss that the cooler gives a change in temperature for a given power. The cold
side gets colder if the hot side is kept as cool as possible. Discuss the concept of a
heat sink.
150
Load
(light bulb)
R=2Ω
Note: Type 1 solar panels (Vmax = 1 V, Imax = 0.4 A) should be wired in series. When
combined, Vmax = 2 V, I max = 0.4 A.
Type 2 solar panels (Vmax = 2V, Imax = 0.2 A) should be wired in parallel. When
combined, Vmax = 2V, Imax = 0.4A.
Day 11: Testing with Solar Cells
Today students will run their cooling circuits with solar cells rather than batteries.
Day 12: Final Test
Explain to students that today they will compete to see who will win the bid to design a
solar chocolate factory. They will be using everything they learned in this activity to
design a factory that both melts and cools chocolate.
They should set up the factory as on Day 8 and the cooling circuit as on Days 10 and 11.
Once teams are set up, you say “GO!” and all students turn on their lamps at once. After
5 minutes they turn off their lamps, and add their chocolate. After 3 more minutes, they
take the melted chocolate out, form it into a shape, and place the chocolate (in the vat) on
the cooler. Everyone who successfully melts and cools the chocolate wins the bid.
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Day One
Worksheet One
Overview of Solar Chocolate Factory Activity
Day 1
You will learn about heat transfer and energy.
Day 2
You will learn about light and heat.
Days 3 and 4
You will design and build a factory.
Days 5 - 8
You will test the factory, rebuild it, and take more data. You will share data with
your classmates and talk about variables. Then you will run a final test to see if it
can melt a chocolate chip.
Day 9
You will learn about electric circuits and build several circuits.
Days
Days 10 and 11
You will use what you learned about electric circuits to build a cooling circuit
powered by solar cells.
Day 12
You will test your factory to see if you can melt a chocolate chip, shape it into a
new form, and cool it.
Day 13
You will have a guest speaker.
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Day Three
Worksheet Two
Name__________________________________________________________________
The Engineering Design Process
In this activity you get to think like a real engineer. Engineers use math and
science to solve problems. Here is your engineering design challenge:
You want to get a bid on a new project to design a more efficient solarpowered chocolate factory. The client is using solar power because it’s
better for the environment, however right now the factory is not working at
its optimal capacity. The factory melts chocolate using passive solar
heating, and then the chocolate is molded into special shapes and cooled
using solar cells. To increase efficiency, the client wants to also be able to
melt chocolate at night and cool it during the day. The client says she’ll
hire all bidders who can store enough solar energy to melt the chocolate
and who can also design the electrical circuits to cool the chocolate.
Designing a new chocolate factory may seem like a daunting task, but you know
just what to do. You consult your diagram of the Engineering Design Process.
Over the course of the next week, you will follow the steps below to design the
factory.
Step 8: Redesign
Step 3: Develop
Possible Solutions
Step 7: Share
the Solution
Step 8: Redesign
Step 7:
Share the
Solution
Step 3: Develop
Possible
Step One: Identify the Problem
What problem are you trying to solve?
___________________________________
___________________________________
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Day Three
Worksheet Three
Researching Different Materials
Materials
Your goal is to let heat and light into the box and trap it there. You will test
different materials to see what works best, and you will record the temperature
inside your factory for each choice.
1. What properties do you want the roof to have?
___________________________________________________________
2. What properties do you want the walls to have?
____________________________________________________________
3. What properties do you want the chocolate vat to have? (The vat is the
container you place the chocolate in.)
____________________________________________________________
4. The materials available to you are foam, aluminum foil, sand, clear plastic,
water, dark paper, and light paper. You know a little bit about these materials
from daily life. Which one do you think will be good for the walls?
____________________________________________________________
5. Which material will be good for the roof?
____________________________________________________________
6. Which material will be good for the vat?
______________________________________________________________
7. How might a daytime roof differ from a nighttime roof?
______________________________________________________________
8. These are your predictions. Now you can do some testing and find out if you
are right.
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Day Three
Worksheet Four
Building Your Test Site
The first thing you need to do is build a model factory. Then you can test different
materials on the walls and roof and see how well they absorb, reflect, and
insulate. Your goal is to first make the factory as hot as possible, and then turn
the light off and retain the heat for as long as possible. You will use a 200-watt
light bulb in place of the sun. Your model must meet the following criteria:
1. The base of the model should be no more than 15 cm by 15 cm.
2. The lamp must be 30 cm above the roof of the model.
3. There should be a way to insert a thermometer into your model.
4. You should make a window so you can see your chip melting.
Sketch your design below and label the materials:
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Day Four
Worksheet Five
Testing the Factory
1. Set up the lamp.
2. Record room temperature (the temperature at a time of 0 seconds).
3. Insert the thermometer in your factory. Place your house under the 200watt light bulb and turn on the light. Place the lamp 30 cm above the roof
of the factory.
4. Record the temperature every 30 seconds for 5 minutes. You can keep
track of your data in the chart on the “Testing Results” worksheet.
5. Turn off the light after 5 minutes, make any desired adjustments to the
factory, and record the temperature for the next 3 minutes.
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Day Four
Roof
Sides
Vat
Floor
Roof
Vat
Sides
Floor
Roof
Vat
Sides
Floor
Material
0
Testing Results
Worksheet Six
Night (light off)
157
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0
Day (light on)
Time (minutes)
Factory Temperature for Different Materials
Temperature (degrees C)
Day Four
Worksheet Six
158
7. Why do scientists and engineers need to work together?
6. Which material is a good absorber? Reflector? Insulator?
5. Do your results agree with your predictions?
4. What changes if any did you make to retain the heat during cooling off? Why?
3. Did your predictions about materials work out?
2. Which material worked best for the roof during heating? Why?
1. Which material worked best for the walls during heating? Why?
Questions
material. (Dashed lines, pencils, and highlighters are also acceptable.)
2. Write a title on your graph. Make a legend in the top right corner and choose a different color to represent each
1. Make a graph with time on the x-axis and temperature on the y-axis. Plot your data.
Graph Your Results
Day 9
Worksheet Seven
Building Electrical Circuits
A Closed Circuit
Circuit
(Materials: 1.5 V battery and light bulb)
First you are going to design a circuit to
turn on a light bulb. Hold one wire from
the light bulb so that it touches the
positive end of a battery and hold the
other wire so it touches the negative end
of a battery. Congratulations, you
have wired a flashlight! (The light will be dim.)
Batteries in Series
Series.
eries
(Materials: Two 1.5 V batteries and a light bulb)
We are going to get a stronger light by using two batteries in series.
series A battery
has polarity. That means one side is positive (+) and one side is negative (-).To
add the voltages, we stack the batteries making sure that the batteries point in
the same direction. Tape the batteries together so that you don’t have to hold
them. Now take the lamp and hold one wire to the (+) end of the top battery and
the other wire to the (-) end at the bottom battery. What is the voltage that drives
the lamp? Is there any change in the lamp?
Using the Breadboard.
readboard
(Two 1.5V batteries, a light bulb, 2 wires, and a breadboard)
We will do the same circuit again using the breadboard. With the breadboard we
don’t have to hold everything with our hands.
Tape one wire to the top of your battery
stack and the other to the bottom. Stick
the other ends in two different rows in
the breadboard. (All the holes in one
row are connected, but different rows
are not connected.) Use the light bulb
to close the circuit. It will look
something like this.
Polarity
(Two 1.5 V batteries, 2 wires, a buzzer/cooler, and a breadboard)
The current flows from high potential (+) to low potential (-), just like water flows
from high to low. It doesn’t matter for the light bulb which way the current flows; it
will heat the filament and light the bulb in either case. But many components will
only work if the current is flowing in the right direction. Components that have a
polarity will have something to mark the (+) and (-) side. In the case of the buzzer
159
Day 9
Worksheet Seven
and thermoelectric cooler, the (+) side has a red wire
and the (-) side has a black wire. Generally, red is
always used for the (+) side.
Use the breadboard to wire this circuit. If you have
done it right you should hear it or feel it!
5. Add a third battery in series and see what happens to the cooler.
6. Loads in Parallel
(Two 1.5 V batteries, 2 wires, 2 lights, and a
breadboard)
Put two lights in parallel as shown in the drawing.
Now the current can either go through either the first
or the second lamp. Compare this to dividing a river
into two smaller currents that each drive a load
before they meet again at the bottom.
What happened to the brightness of the lamps? What happens if you remove one
light?
7. Make up a new circuit. You can use fans, motors, lights, buzzers, or the TE
cooler. You can use several batteries and try several combinations.
Fan:
Buzzer:
TE cooler:
Motor:
Lights
Polarity: Yes
Polarity: Yes
Polarity: Yes
Polarity: No
Polarity: No
3-13V
3-7 V
2-20 V
1.5-3 V
1.5-6 V
Draw the circuit and describe what it does.
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Day 9
Worksheet Eight
Welcome to Electric Circuits!
Helpful Terms
Term
Current
Voltage
Resistance
Power
Symbol Units Definition
I
Amps A measurement of the flow of electrons in a wire
V
Volts The potential difference that makes electrons flow
through a wire
R
Ohms Caused by a load, converts energy in a circuit into
another form
P
Watts The rate at which energy is transferred
Circuit Elements
Wires are made of metal (good conductor) covered with plastic (good
Wires
insulator). Charges flow through them.
The breadboard is like a grid of wires. Basically it is a way to connect
Breadboard
wires together easily and neatly. (See more on breadboards below.) You
could simply hold two wires so that they touch a battery and a light bulb.
This would work, but your hands might get tired.
Batteries are voltage sources. They make current flow. They have a
Batteries
positive and negative end. We think of current as flowing out the positive
end and in the negative end.
Solar panels are sources. The solar panel uses energy from light and
Solar Panel
converts it into a voltage. Since it has a voltage, the solar panel can make
current flow through a circuit. (Remember: current flows out the (+) end
and in the (-) end.
Thermoelectric Thermoelectric coolers are loads. They draw current from your circuit and
use it to move heat from the hot side of the cooler to the cold side. If you
Coolers
hold the cooler with the wires facing toward you with the red wire on the
right and the black wire on the left, the hot side is facing down. These
coolers work best if you place them on a heat sink, a piece of metal that
helps draw away the excess heat. (The thermoelectric cooler “pumps” heat
from the cold side to the hot side. For more information please visit the
Frequently Asked Questions sections of the TE Technology, Inc. website at
www.tetech.com/techinfo/.)
A light bulb is a load. It uses current from your circuit to heat a filament.
Light Bulb
A fan is a load. It draws current from your circuit and uses it to generate
Fan
wind.
161
Day 10
Worksheet Nine
Breadboard Fact Sheet
Circuits are built on breadboards, which are special platforms with many holes on the
surface and multiple wires underneath. The surface of a breadboard looks like this:
Figure 1 – Breadboard Surface
Photo of breadboard from Iguana Labs website at www.iguanalabs.com.
The circuit components are placed into the holes. The wires in the middle layer of the
board connect the components. The wire layout is shown in Figure 2 below. Note that
there are two sets of long wires at the edges of the board. The middle of the board
contains two strips of shorter wires.
Figure 2 – Breadboard Wire Connections
Photo of breadboard from Iguana Labs website at www.iguanalabs.com.
162
Day 10
Worksheet Ten
Name _______________________________________________________
Cool It! Directions
Now that you have some basic knowledge of electric circuits, you will use that
knowledge to use a solar panel circuit to run a thermoelectric cooler.
You have the following materials available:
•
Solar panels
•
TE cooler
•
Breadboard
Work with your partner to figure out how to connect the circuit elements. Draw a
picture of your circuit in the space below.
Engineering Connection
Nerves in your body are like wires. Small amounts of electricity travel down your
nerves to tell your brain what your eyes are seeing or your fingers are touching.
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Day 10
Worksheet Eleven
Solar Panel Fact Sheet
A solar panel is a voltage source. A solar panel uses energy from light and
converts it into a voltage. Like a battery a solar panel has polarity. In a solar
panel, the red wire is the high voltage (+) and the black wire is the low voltage (-).
A solar panel has a maximum voltage and a maximum current, which are marked
on the back of the cell. There are two types of solar panels available for this
activity.
Type 1: Vmax= 1V and Imax= 0.4 A
Type 2: Vmax= 2V and Imax= 0.2 A
That means that under enough light, the solar cell can produce up to Vmax voltage
and at the most deliver Imax current.
You can put the sources in series to add
voltage, but the current through the sources
will be limited to Imax.
You can put the sources in parallel to add
the currents, but the voltage will be limited
to Vmax.
The solar panels produce a
voltage when light shines on
the surface. If the day is sunny,
try the experiment by a window
in direct sunlight, otherwise use
a 200 watt bulb. If the sun is
bright, what is the maximum
current and voltage supplied to
the TE cooler in this example?
The 200 watt bulb produces more heat than light. If the solar panel gets too hot, it
will not work efficiently. You can try fanning the panels if this happens, or you can
put a transparent sheet between the 200 watt lamp and the solar panel.
164
Day 12
Worksheet Twelve
Thermoelectric Cooler Fact Sheet
The thermoelectric cooler is a semiconductor device. Electric current moves heat
from the cold side to the hot side.
The TE cooler has a red (+) and black (-) wire attached. Connect the red wire to
the positive voltage and the black wire to the negative voltage. Try this with a 3 V
battery first to check which side of the cooler is the cold side.
The TE cooler maintains a temperature difference between the cold and the hot
side. To get the cold side as cool as possible, try to keep the hot side as cool as
you can by removing excess heat. To do this you can use a heatsink. A heatsink
is a device that exchanges heat with air. In this activity, it is simple a metal plate.
Use the strip thermometers to measure the temperature on the cold side and the
hot side.
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Day 12
Worksheet Thirteen
The Ultimate Challenge
On the final day, the client will visit your classroom to see your model factories
at work. She will hire anyone who can successfully melt and cool the
chocolate.
Procedure
1. Set up your factory and cooling circuit.
2. When your teacher gives the signal, turn on your lamp.
3. After five minutes have passed, your teacher will tell you to turn off your
lamp and add the chocolate.
4. After three additional minutes have passed, the client will check to make
sure your chocolate is melted.
5. Then you will place your chocolate vat on the thermoelectric cooler for five
minutes. The client will check to see if your chocolate has cooled.
166
Any steps skipped and why
Conclusions
By the end of this activity, students should be comfortable using the engineering design
process to solve a problem; be able to work as a group to develop a prototype; understand
how solar energy can be used for passive heating and electricity generation; understand
basic electric circuit theory; know how to develop their own circuit to cool chocolate with
a thermoelectric cooler; and be familiar with some forms of renewable energy.
Vocabulary
•
•
•
•
•
•
•
•
•
•
•
prototype
solar energy
passive heating
renewable resources
insulation
reflection
absorption
heat transfer
conduction
convection
radiation
•
•
•
•
•
•
•
•
•
•
•
circuit elements
polarity
breadboard
heat sink
series and parallel circuits
current
voltage
power
resistance
source
load
References
Fossil Fuels: Coal, Oil, and Natural Gas
• Fossil Fuels
http://www.energyquest.ca.gov/story/chapter08.html
Solar Energy
• How Solar Cells Work
http://science.howstuffworks.com/solar-cell.htm
•
North Carolina State University Solar House Design
http://www.ncsc.ncsu.edu/solar_house/NCSU_solar_house_design.cfm
•
Solar Energy – Energy from the Sun
http://www.eia.doe.gov/kids/energyfacts/sources/renewable/solar.html
167
•
Solar Powered Chocolate Factory
http://grenadachocolate.com/homepower_article.pdf
Wind Power
• KidWind Project
http://www.kidwind.org/materials/sciencefairideas.html
Electric Circuits
• Iguana Labs: Basic Definitions and Concepts
http://www.iguanalabs.com/basicdef.htm
•
WhyFiles: Circuits
http://whyfiles.larc.nasa.gov/text/kids/Problem_Board/problems/electricity/circuits2.h
tml
Extensions
•
•
•
•
•
Have students read the article “Spray-On Solar-Power Cells are True Breakthrough”
(http://news.nationalgeographic.com/news/2005/01/0114_050114_solarplastic.html)
and discuss how the steps of the engineering design process were used to invent this
material.
Place the Solar Chocolate Factory in a cooler full of ice and try to get it to melt the
chocolate.
Reverse the problem: Keep the chocolate chip (or ice) from melting. Try insulation or
evaporative cooling. (Place a wet cloth over the box and fan air over the top.)
Have kids add windows to their factories and have a contest to see whose chocolate
melts first.
Make a PowerPoint presentation for your kids about a real solar-powered chocolate
factory. (Information available at grenadachocolate.com/homepower_article.pdf.)
168
By Karen Panetta, Cissy George, Masumi Patel, Katie Cargill,
Erica Wilson, Peter Wong, and Meredith Knight
Binary and Communication Systems
Learning Strand:
Activity Time:
300 minutes, minimum of six classroom
sessions
5
Group Size:
4 – 5 students
Purpose
The purpose of this activity is to introduce students to the concept of binary coding as a
language and its practical applications in digital and communication systems. In this
activity, the students will…
1)
2)
3)
4)
Use math to translate from decimal to alphanumeric representations
Be introduced to the differences between digital and analog design
Talk about the box (board) design and information flow of binary signals
Relate the topics introduced to real world applications, such as digital systems
found in CD-ROMs, video games, digital cameras, and cellular phones
5) Discuss the history of secret codes. This includes examples such as spies and
code breaking during World War II.
6) Discuss the types of engineering skills that were used in this project design. It
is assumed that students will have had an overview of the type of engineering
fields available such as:
Computer Engineering
Electrical Engineering
Human Factors/Human Psychology Engineering
Chemical Engineering
Civil Engineering
Mechanical Engineering
169
Outcomes
By the end of this activity, students will be able to...
1)
2)
3)
4)
Translate decimal to binary representation
Translate binary to decimal representation
Understand the difference between digital and analog designs
Understand how digital systems such as binary code relate to real world
applications, for example in CD-ROMs, video games, digital cameras, and
cellular phones
5) Understand that working with binary is cumbersome, error prone, and difficult
for humans to read
Other skills practiced in this activity include logical thinking and problem solving.
CONNECTIONS TO “BINARY IN A BOX”: As technology in our society
progresses, more things that we use in daily life are becoming digital. Engineers use the
binary system in the design of many of these digital devices.
OVERVIEW OF THIS ACTIVITY: This project is intended to give students a deeper
appreciation for communication systems and an understanding of how binary symbols are
used to transmit information. This write-up is divided into six sections. The first session
includes a general introduction to engineering, and the second is an introduction to
communication systems. The third session will discuss the concept of the binary number
system and its history. In the fourth and fifth sessions, students will learn to decode and
encode binary in a series of activities, and finally, in the sixth session the students will
learn how the binary system is connected to the communication systems they learned
about previously, as well as their everyday lives.
Binary code is used in all digital technology, from CD players to cellular phones
to computers to video games. The properties of binary code allow information to be
interpreted quickly and easily by electronic circuits. Binary notation uses two digits, 0
and 1, to transmit information. The 0 and 1 can represent “off” and “on” or even “open”
and “closed” in an electronic circuit.
In most everyday situations, we rely on a “base 10” number system. This means
that we represent numbers using the following set of ten numerals: 0, 1, 2, 3, 4, 5, 6, 7, 8,
and 9. When we represent numbers above nine (such as ten and higher), the position of
the numerals becomes important. In “ten” the zero is in the ones column (the column
170
furthest to the right) and the one is in the tens column (the column second furthest to the
right); in “eleven” there is a one in the tens column and a one in the ones column; and so
on.
In binary, there are only two numeral options: 0 and 1. When we represent
numbers above one, the location of the numbers becomes important. Representing the
number “two” in binary requires putting a “1” in the second column from the right and a
“0” in the column all the way to the right. (Notice—we can’t call them “ones columns” or
“tens columns” anymore because we’re not in the base ten system.) Three requires a “1”
in the right column with another “1” next to it. Following this logic, the numerals 0
through 9 are represented in binary as follows:
Numerals
zero
one
two
three
four
five
six
seven
eight
nine
ten
Binary
Representation
0
1
10
11
100
101
110
111
1000
1001
1010
A more systematic way of “translating” base ten numbers into binary numbers is
through the following chart. The headings of the columns represent “two” to the power of
the column’s location, starting with 0 at the right most column. (Two to the eighth power
is 128, two to the seventh power is 64, and so forth.) So, to translate the binary number
10110101 into base ten, you would write each one and zero under the appropriate column
heading based on its location, multiply the column heading by either one or zero, and add
up the results.
27
26
25
24
23
22
21
20
128 64
32
16
8
4
2
1
1
0
1
1
0
1
0
1
128
0
32
16
0
4
0
1
128 + 0 + 32 + 16 + 0 + 4 + 0 + 1=181
10110101 translates into 181.
One useful property of using the binary system is that two numbers can be
multiplied in binary and in the base ten systems with the same result. For example,
multiplying two times three using the binary system is:
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10
x 11
10
100
110
two
times three
The result, 110, represents “six” in the list of binary numbers above.
In summary, binary is another set of symbols that can be used to encode
information. The numerals zero and one are used to represent information instead of zero
through nine. For additional information, see the References section.
Materials for Activity
•
•
•
•
access to an Internet connection
worksheets
pennies
binary box
To prepare for this activity, review all of the following components.
Session 1: Introduction to Engineering
This session is intended as a review of the different types of engineering and how
we use engineered products in our everyday lives. This portion will especially showcase
engineering careers that may be interesting to girls.
The American Society of Engineering Education (ASEE) defines engineering as
follows:
Engineering is the art of applying scientific and mathematical principles, experience,
judgment, and common sense to make things that benefit people. Engineers design bridges and
important medical equipment as well as processes for cleaning up toxic spills and systems for
mass transit. In other words, engineering is the process of producing a technical product or system
to meet a specific need.
Engineers have many different types of jobs to choose from, including research, design,
analysis, development, testing, and sales positions. If you are interested in discovering new
knowledge, you might consider a career as a research engineer. If you are imaginative and
creative, design engineering may be for you. The work of analytical engineers most closely
resembles what you do in your mathematics and science classes. If you like laboratory courses and
conducting experiments, look into becoming a development engineer. Sales engineering could be a
good choice if you are persuasive and like working with people.
Engineering work is also organized by traditional academic fields of study. The five largest of
these are chemical, civil, electrical, industrial, and mechanical engineering. There are also more
172
specialized engineering fields, including aerospace, ocean, nuclear, biomedical, and environmental
engineering.1
Teachers may consider asking an engineer to come into the classroom and speak
about her job. Teachers can contact a local university that has an engineering department
(check the university’s website), a local engineering company, or a professional society,
such as the American Society of Mechanical Engineers, the American Society of Civil
Engineers, the Society of Women Engineers, or the National Society of Black Engineers.
Session 2: Presentation on Communication Systems
a. Introduction to Communication Systems
Through this presentation, the students should gain an understanding of
communication systems, including the concepts of a source, encoder,
transmitter, receiver, decoder, storage, retrieval, and destination. Students will
also be introduced to different types of communication technologies and
systems such as audio, visual, printed, and mass communication systems.
b. Introduction to Engineering Fields Involved in Communication Systems
Students should learn more about the types of engineering that are involved
with the construction, maintenance, and use of telecommunication systems.
Specific examples include civil engineering, telecommunications engineering,
and electrical engineering.
Session 3: Introduction to the Binary Number System
(Be sure to point out the contributions of women in computer science.)
During this session, students will be introduced to the concepts of binary language
and the history of the binary number system. This lesson should include the following
main points.
Historic Points
Although it is commonly believed that binary numbers were first used by the
German mathematician Leibniz, new evidence indicates that binary numbers were used in
India before the second century A.D, more than 1500 years before their use in the West.
For example, an ancient musician named Pingala used binary code to notate musical
meters in his text “Chhandahshastra,” which translates to “the science of meters.”
Pingala, however, wrote binary numbers from right to left, rather than from left to right as
we do today, and also started his values with 1, rather than 0. For example, in Pingala’s
form of binary, 0000 would be equal to 1, and 1000 would represent 2. See
http://mathforum.org/epigone/historia_matematica/glaytheldwal for more
information on the use of binary numbers in ancient Indian history.
1
Accessed at www.asee.org/precollege/engineering.cfm#whatiseng in January of 2004.
173
When the German mathematician Leibniz began using binary around 1666, he
was looking for a way to represent logical thought through a universal, mathematical
language. He believed that the universe could be reduced to “on/off” units and used
binary to represent naturally occurring opposites, such as yes and no, on and off, dark and
light, and male and female. It wasn’t until later, when popular belief started supporting
this alternative way of thinking, that Leibniz began to refine his ideas and create the
binary number system. See http://www.gowcsd.com/master/ghs/math/furman/binary/
hist.htm for more information.
Another contributor to binary code was George Boole who created Boolean
Logic. Boole was determined to find a way to encode logical arguments in an indicative
language that could be manipulated and solved mathematically. Around 1954 he
proposed a theory in his document, “An Investigation of the Laws of Thought, on Which
Are Founded the Mathematical Theories of Logic and Probabilities,” that logical
processing could be reduced to only two objects. These objects are now the famous
yes/no, true/false, zero/one approaches. Unfortunately, at the time Boole’s idea was
criticized and ignored by the academic community. More about George Boole can be
found at http://www.kerryr.net/pioneers/boole.htm.
Today binary code is most often used in electronics and computer programs. The
first person to use binary to write a computer program, and still one of the few female
pioneers of the computer age, was a woman named Ada Byron. Ada was mostly selftaught mathematically but communicated frequently with all of the great scientists of her
time and was well respected in the field. She worked most closely with a man named
Charles Babbage, who had created an “analytical engine.” In 1843, she used Bernoulli’s
numbers and made them into something that was readable by the analytical engine,
bypassing the step of the human controller. This project is now widely considered to be
the first computer program. Ada is the only woman to have a computer programming
language named after her. The Pascal-based language ADA is named after Ada Byron.
For more information see http://www.kerryr.net/pioneers/ada.htm.
One of the first computer scientists was a Vassar graduate named Grace Murray
Hopper. She started her career as a math professor and was later hired as a research
fellow for the Bureau of Ordinance Computation Project at Harvard University, where
she did computations on military machines through WWII. Grace’s best-known
contribution to the world of computer science was the invention of the compiler, an
intermediate program that translates English language instructions into the language of
the target computer. She claims she did this because she was lazy and was hoping to go
back to being a mathematician. Grace’s work, including subroutines and formula
translation, foreshadowed many developments that are now the framework of digital
computing. Her work helped bring computer science and technology to where it is today.
More on Admiral Grace Hopper can be found at http://www.sdsc.edu/ScienceWomen/
hopper.html.
174
Mathematical Points
1. Base ten (decimal) notation
2. Place value
3. Exponential notation
4. Numbers as symbols used to communicate information
5. Ways of translating binary numbers into decimals, and decimals into binary
numbers
6. Properties of binary numbers
Resources:
•
History of Binary PowerPoint Presentation
www.stemteams.org
•
Past Notable Women of Computing
www.cs.yale.edu/homes/tap/past-women-cs.html
•
Teaching Tips: Other Activities to Teach Students about Binary Numbers
www.gowcsd.com/master/ghs/math/furman/binary/teach.htm#tips
Session 4: Binary Encoding Activity*
*If teacher has access to the Binary Boxes. If not, then use the alternative binary web-based activity below.
MATERIALS:
• Building switchboards (boxes)
• Table for assigning four digit patterns to letters
• Codes for decoding
DIRECTIONS:
1. Introduction: At the beginning of class, explain to students that they will be
decoding messages using special boards. Each board has its own code for
different letters. There are four different switches; therefore we can have only 16
combinations (24). Each switch will be in one of two different positions: on or
off. On = 1 and off = 0. Each letter has its own code, for example, on this box
(hold up a box), “off, off, off, off” or “0000” lights up a light beneath the letter
“A,” while “1111” represents “S.”
2. Individual activity: Have each student take out a piece of paper and write down
“0000” on the first line and “1111” on the 16th line. Since there are 16 possible
combinations of zeros and ones, have students come up with the remaining 14
combinations of zeros and ones.
175
3. Explanation of boards: Once most
students are finished with the
patterns, explain how to use the
boards. Explain that up = 1 and
down = 0. After you set the
switches in an on/off pattern, press
“reset” and the light will appear.
Write down which letter
corresponds to the pattern.
4. Creating a “key”: Divide the class
into groups. Ideally, there should be two students per box, but there can be up to
four students. Have one student be a “scribe” and the other a “switcher.” The
scribe should work from the list of combinations and tell the other student which
pattern to set. The switcher then reports which light appears. Test all 16
combinations and create a “key” for that box. (Remember, each box is different.)
5. Decoding: Once the group has all
of the letters, then pass out the
code that goes with the box.
(Since each box has only 16
letters, be sure to give the right
code for the right box). Instruct
the students to switch roles, so the
scribe can get a turn switching.
(Often, girls are relegated to the
“note taker” role, so switching
roles is important!) Students use
the key they just decoded to
interpret the message. The group
with the code that says they are the winners gets a prize.
6. Switch Boards: Switch boards and codes and have students decode other codes.
7. Group Discussion: At the
end of the class, collect the
boards and have a full group
discussion using the
discussion questions below.
Be sure to stress how binary
is used in many everyday
forms of technology, such as
computers, CD players,
cellular phones, and video
games.
176
Session 5: Binary Decoding Activity
Create new codes: Explain that the wires can be rearranged so that the combinations now
correspond to different letters. Students rearrange the wires and then try the different
combinations of 0’s and 1’s to come with a new key. Students come up with a new
message using their 16 letters. They write the code for that message and give it to another
group to interpret. Groups should follow the steps listed in the “Binary Encoding
Activity” worksheet.
Session 6: Uses of Binary in Communications
and Everyday Applications
Materials: Everyday Applications of Binary PowerPoint Presentation
This session can be used for review of the binary number system as a method of sending
messages, as well as an interactive discussion of everyday applications of binary
numbers. Some questions to guide discussion include:
1. With only four switches on the box, why couldn’t we use all the letters of the
alphabet? How many switches would we need to include to use all the letters?
2. What else could we use digital systems for?
Possible answers: Video games, CD-ROMs, digital cameras, and cell phones.
3. How long did it take you to translate the message from binary numbers to letters?
How would your life be different if your CD player or cell phone took that long to
decode information?
4. What does it mean when you say your video game system is “64 bit”? How is
something that is “64 bit” different from something that is “32 bit”?
Alternative Activity: Binary Box Online
If binary boxes are not available to your class, you can simulate the activity in Session 4
on the Tufts Binary Box website (http://www.engineering.tufts.edu/stemteams/
binarybox/STEMSrb.html).
1. Have all students visit the website above. The first page will look like the figure
on the next page.
177
2. Have the students click on the
introduction, read it, and then
proceed to the main activity by
clicking on the black arrows.
3. The Binary Box page will look like the figure below. It may be helpful to have the
students copy the binary code onto a sheet of paper and write the letters below the
numbers as they go, or they can use the worksheet provided in the worksheet
section.
178
STUDENT WORKSHEET
Translating Decimal to Binary
Name: _________________________
Explanation: Below are three groups of columns. One group is the “letter”
column; the second group is the “decimal” column; and the third group is the
“binary number” column. Using your understanding of binary numbers,
translate the letter and decimal into a binary number.
Letter
Decimal
10
1
A
0
B
1
C
2
D
3
E
4
F
5
G
6
H
7
I
8
J
9
K
1
0
L
1
1
M
1
2
N
1
3
O
1
4
P
1
5
Q
1
6
R
1
7
S
1
8
T
1
9
U
2
0
V
2
1
W
2
2
X
2
3
Y
2
4
Z
2
5
Binary Number
16
8
179
4
2
1
STUDENT WORKSHEET
Translating Binary to Decimal
Name: ___________________________
Explanation: Below are three groups of columns. One group is the “letter”
column, the second group is the “decimal” column, and the third group is the
“binary number” column. Using your understanding of binary numbers,
translate the binary number into decimal notation.
Letter
Decimal
10
Binary Number
1
16
8
4
2
1
A
1
1
0
0
1
B
1
0
1
1
1
C
1
0
1
0
1
D
1
0
0
1
1
E
1
0
0
0
1
F
0
1
1
1
1
G
0
1
1
0
1
H
0
1
0
1
1
I
0
1
0
0
1
J
0
0
1
1
1
K
0
0
1
0
1
L
0
0
0
1
1
M
0
0
0
0
1
N
1
1
0
0
0
O
1
0
1
1
0
P
1
0
1
0
0
Q
1
0
0
1
0
R
1
0
0
0
0
S
0
1
1
1
0
T
0
1
1
0
0
U
0
1
0
1
0
V
0
1
0
0
0
W
0
0
1
1
0
X
0
0
1
0
0
Y
0
0
0
1
0
Z
0
0
0
0
0
180
Teacher Answer Key
Letter
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Answer Key: Binary - Decimal
Conversion Worksheet
Decimal
Binary Number
10
1
16
8
4
2
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
181
Letter
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Answer Key: Decimal - Binary
Conversion Worksheet
Decimal
Binary Number
10
1
16
8
4
2
1
2
2
2
1
1
1
1
1
5
3
1
9
7
5
3
1
9
7
5
3
1
4
2
0
8
6
4
2
0
8
6
4
2
0
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
0
0
0
0
0
0
0
0
1
0
0
0
0
1
1
1
1
0
0
0
0
1
0
0
0
0
1
1
1
1
0
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
1
0
1
0
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
2
2
2
1
1
1
1
1
182
Note: We decided to create boxes with only four switches. Thus, we had to figure out
which messages we were going to code, then assign different patterns of ones and zeros
(on/off) to different letters in order to create the secret messages for the students to
decode.
Each box is numbered 1 – 10, and each box has its own message.
message
#
1
2
3
4
5
6
7
8
9
10
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
c
d
e
h
I
k
l
n
o
p
r
s
t
u
v
y
b
c
e
f
h
I
l
n
o
p
r
s
u
v
w
y
a
b
c
d
e
I
j
l
n
p
r
s
t
u
v
y
a
d
e
f
h
I
l
m
n
o
r
t
u
w
y
z
b
c
d
e
g
h
j
k
l
o
q
r
t
u
x
y
a
b
e
f
g
h
I
k
n
o
p
r
s
t
u
v
a
b
c
e
f
h
j
k
m
o
p
r
s
t
u
w
a
b
d
e
I
j
k
l
n
o
r
t
u
v
w
x
a
d
e
g
h
I
k
l
m
n
o
r
s
t
v
w
a
d
e
g
h
I
l
n
o
r
s
t
u
v
w
y
Messages:
Message 1: The key to success is discipline.
Message 2: Believe in yourself.
Message 3: Celebrate diversity.
Message 4: You are the winner.
Message 5: You broke the binary code.
Message 6: Engineering is fun.
Message 7: Reach for the stars.
Message 8: Turn an idea into an invention.
Message 9: Imagination is more important than knowledge.
Message 10: You learn new things every day.
183
Codes for Binary Boxes in Binary Numbers
CODE 1
CODE 2
CODE 3
CODE 4
CODE 5
CODE 6
CODE 7
CODE 8
CODE 9
CODE 10
1100
0011
0010
1111
1001
1101
1011
1100
1010
1000
0101
0111
0000
1011
1001
0111
0011
0101
1000
0000
0011
0101
1001
0000
1101
0101
1010
1001
1111
1000
1100
0000
1010
0010
0010
1000
0100
0110
1000
0010
0010
1011
0110
1000
0100
1011
0011
0000
0010
0101
1100
1000
0010
0100
0111
0100
0001
1010
0000
1100
0100
1110
1001
1100
0101
0010
1111
0000
0010
0110
0101
0010
1101
0010
1011
1101
0000
0000
0010
1011
1011
1111
1000
1100
1010
1011
0010
0110
0011
0011
0101
1110
0100
1010
1011
0101
1100
1111
1011
0100
0010
1101
0110
1000
1000
0010
1010
1100
0101
0011
0001
1001
0010
0011
0111
1100
0011
1110
1000
0100
1011
0100
1001
1011
1101
0101
0011
1100
1101
0000
1011
1100
0000
1000
0100
0010
0011
0000
0100
1000
1011
1001
0000
1000
0100
1000
1101
0011
1000
1011
0100
1001
1000
0001
0100
1011
0000
0100
1001
0110
0100
0111
0010
0101
1100
1000
1010
1011
0010
0101
1000
1110
1010
1011
1101
0000
1001
1101
1001
0100
0000
1001
0110
1001
1010
1111
0111
0010
0001
0011
0010
184
0110
0010
0000
1001
0111
0111
0010
1110
1011
0100
0101
0111
0011
1010
0010
1101
0010
1001
1111
0001
0000
1111
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
2
0
4
12
4
2
11
3
7
6
2
4
5
1
Name: ______________________________________
Code 1
Code 2
Code 3
1
2
4
5
10
13
11
2
0
2
0
15
185
12
4
4
5
9
12
STUDENT WORKSHEET
7
6
8
3
4
5
15
7
14
8
11
2
4
12
13
10
10
0
11
11
0
5
2
2
12
6
11
15
3
11
Code 4
Code 5
Code 6
Code 7
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
11
2
15
14
3
8
9
9
0
4
13
12
2
6
5
8
0
0
2
11
10
4
2
9
2
186
9
11
7
11
6
3
11
8
4
13
4
12
2
5
5
3
6
3
13
12
12
6
13
1
8
0
3
9
8
11
14
2
2
12
8
3
10
Code 8
Code 9
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
Binary
Number
Letter
Decimal
5
5
0
11
8
8
8
12
14
0
10
10
3
4
8
11
5
8
13
9
13
0
0
0
3
8
9
187
13
8
13
5
9
11
4
4
2
5
9
3
12
8
0
4
8
11
9
Code 10
Letter
Binary
Number
Decimal
Letter
Binary
Number
Decimal
11
15
4
8
5
12
7
3
6
10
2
188
0
2
9
13
7
2
9
7
15
2
1
14
0
15
STUDENT WORKSHEET
Name: _______________________________
Online Binary Box Worksheet
Use website:
http://www.engineering.tufts.edu/stemteams/binarybox/STEMSrb.html
Binary
Code _______ _______ _______ _______ _______ _______
Letter
_____
_____
_____
_____
_____
_____
Binary
Code _______ _______ _______ _______ _______ _______
Letter
_____
_____
_____
_____
_____
_____
Binary
Code _______ _______ _______ _______ _______ _______
Letter
_____
_____
_____
_____
_____
_____
Binary
Code _______ _______ _______ _______ _______ _______
Letter
_____
_____
_____
_____
_____
_____
Binary
Code _______ _______ _______ _______ _______ _______
Letter
_____
_____
_____
_____
_____
Solution: _______________________________________________________
189
_____
STUDENT WORKSHEET
“You are the Wizard”
Binary Quiz
1. When creating the binary conversion table, HOW do we get the
numbers to fill in the title row? You may use sentences or a
mathematical formula.
2. What are the first five numbers in the title row?
_____, _____, _____, _____, _____
3. Binary: 11001010
Decimal: _______________
4. Binary: 1000111
Decimal: _______________
5. Decimal: 200
Binary:
_______________
6. Decimal: 111
Binary:
_______________
7-9. Name three uses of binary: ___________________
___________________
___________________
10. How many bits are in a byte? __________
190
Sample Rubric for Performance Assessment
Activity Title: Journal Entries
Grade Level 8
Criteria
Pre-visit
Questions
1
Beginning
Student
completed only
1or 2 questions.
2
Developing
Student
completed 3
questions.
3
Proficient
Student
completed all
questions with
grade level
responses.
4
Advanced
Student completed
all questions with
thorough and wellorganized
responses.
Student notes are
Student copied
Student copied
very well done.
Very few notes on
notes sufficiently,
Binary Notes
notes
Shows
binary.
and shows some
sufficiently.
understanding of
understanding.
binary system.
Complete
understanding of
Binary Box lesson
present. Provided
Complete
Did not follow
Understanding understanding of useful feedback
directions well.
of Binary Box
Binary Box lesson both orally and in
Did not work well lesson present. present. Provided writing. Very
Binary Box
with group. Failed Provided useful useful feedback involved in project.
Lesson
to provide useful feedback either both orally and in Expressed interest
in continuing
feedback either
orally or in
writing. Very
working with binary
orally or in writing. writing.
involved in
numbers. Asked
project.
many questions
about the binary
number system.
Teacher Comments:
191
Weight
(X factor)
Subtotal
Conclusions
By the end of this activity, students should:
1. Be able to competently translate decimal to alphanumeric representation
2. Know the difference between a digital and analog system
3. Understand the application of binary code in technology
The teachers who did this unit in their classrooms used two different methods of
assessment. One teacher assessed students based on homework and a quiz. (See attached
quiz.) The other teacher assessed students based on their journal entries in response to
different questions. Both rubrics and assessment tools are included.
Vocabulary
binary: A numbering system that uses 0 and 1 rather than all ten digits. The binary
number system is the system read by most computers and other forms of
technology.
analog systems: In analog systems, waves are used in their original form.
digital system: Systems where analog waves are converted into numbers before they are
used.
alphanumeric representation: A form of data that expresses letters in the form of
binary code.
References
The Socratic Method: Teaching by Asking Instead of by Telling
www.garlikov.com/Soc_Meth.html
A step-by-step lecture by Richard Garlic on binary using the Socratic method.
How Do We Talk to Machines?
spaceplace.jpl.nasa.gov/vgr_fact2.htm
A very simple introduction to binary language designed by NASA.
192
By Anne Sullivan, Emily Shattuck, Peter Wong, and Meredith Knight
Simple Circuits
Learning Strand:
Engineering design
Identifying and using symbols
Concepts:
Electrical engineering design
Communication technologies
Activity Time:
1 – 2 class sessions
2
Group Size:
2 – 3 students
Purpose
The purpose of this activity is to understand how electricity and simple circuits work, and
how switches apply to binary language. Students will also identify and generate symbols
of basic components in a simple electric circuit. In this activity, students will
1. Think about how electricity plays a part in their lives
2. Learn about the different aspects of electricity and the electric circuit
3. Learn about the role of different types of switches
4. Build a simple electric circuit that will illuminate a light bulb
5. Be introduced to the concept of binary code
Outcomes
By the end of this activity, the students will
1. Understand the make-up of electric circuits
2. Combine all the entities of an electric circuit to build a working circuit
3. Understand the universal language of symbols used in electric circuit design
and be able to interpret a diagram representation of a circuit design
4. Understand how binary code plays a role in electronics
Other skills practiced in this activity include teamwork, data recording, and idea
presentation.
193
CONNECTIONS TO THE ENGINEERING DESIGN PROCESS: Students use
electronic circuits and switches on a daily basis. Electrical engineers design circuits as
simple as those used to power calculators and as complex as those used in the operating
system in a car. In this activity, students play the part of the electrical engineer and design
a simple circuit, build it, and redesign it if it does not work properly. Students also
communicate their designs, both in the form of a diagram and symbols, as well as
verbally.
OVERVIEW OF THIS ACTIVITY: After brainstorming about the uses of electricity
and circuits and learning about circuits, voltage, currents, and different types of switches,
students will have all the tools they need to create a working circuit.
Circuits
At the simplest level, circuits must contain three components:
1) Power source: battery, solar cell
2) Load: light bulb, motor, TV
3) Wires
An example of this is shown in Figure 1, with a battery as a power source, a light bulb as
a load, and a switch in one of the wires. The switch allows current to flow or prevents it
from flowing. The red arrows show the direction of current flow.
Power Source
The power source will always have
two terminals—positive and
negative—and will push electrons out
of the negative terminal at a certain
voltage (the difference in charges
between the positive and negative
terminals of the power source). In
order for these electrons to flow from
the negative terminal to the positive
terminal, there must be wires
connecting the two terminals, and if
there is a switch, it must be closed.
When we have some sort of conductor
that allows electrons to flow from the
negative to the positive terminals of
the power source, we have a circuit.
Figure 1: Simple Circuit
194
Load
Since the moving electrons have energy, they can do work. When a load is incorporated
into the circuit, the energy from the moving electrons creates energy in various forms
depending on the load. In the case of Figure 1, the electrons illuminate the light bulb
rather than going all the way around the circuit back to the positive terminal of the
battery.
Units
The three important units used when discussing electricity are voltage (V), current (I),
and resistance (R).
Voltage:
The amount of energy in a power source or the difference in charge
between the positive and negative sides of a power source. The
voltage determines how many electrons will flow through the circuit.
Voltage is expressed in volts.
Current:
The amount of electric charge flowing past a specific point per unit
time or the flow rate at which electrons are flowing through the wire.
Current is measured in amps.
Resistance: The opposition of a load or wire to current passing through it.
Resistance of a load would be how much energy the load takes to
operate, and resistance of a wire would be how much current it
allows through.
The basic equation that ties these three units together is:
V=IxR
This equation states that the current is equal to the voltage divided by the resistance.
Materials
•
•
•
•
•
•
•
•
•
1.5 volt battery
wire (Number 18 or 20 copper wire recommended)
light bulb (flashlight bulb is sufficient)
knife switch
Scotch™ tape
wire strippers (Note: Teacher can show students how to use wire strippers with
insulated wire, or copper, non-insulated wire can be used instead.)
Rubber bands (optional)
Paper clips (optional)
Brass tacks (optional)
195
You may want to instruct students to bring in certain materials from home a few days
before the activity. Possible household items include: aluminum cans, batteries, and
office supplies, such as paper clips and rubber bands.
Group Brainstorm:
1. Ask students to list how many times they use electricity in a typical day. Or,
brainstorm what a day would be like without electricity. Share responses as a class.
Introduction:
2. Simple circuit: Explain that all of these real life applications of electricity include
many simple electric circuits. A circuit is a continuous loop of material that carries
electric current. Electricity works similarly to how water flows through a pipe. Water
is pushed through pipes by a pump, as electric current is pushed through wires by a
battery.
3. Voltage and current: Voltage is the amount of electricity. Current is the amount of
electricity that flows through wires.
4. Switches: Explain that most electronic devices have an on/off switch. (Students are
probably familiar with the power button on a television or computer.) Simple circuits
also have switches that have two positions: on or off. When a switch is on, the circuit
makes a continuous loop, and electricity is conducted. When a switch is off, there is a
gap in the circuit, and electricity does not flow.
a. One example is a “knife” switch in which the parts are visible (shown below).
b. Ask students to think of things that resemble a knife switch.
Examples:
Drawbridge: Vehicles and people can only cross a
drawbridge when it is down. The same applies to electricity. It
can only flow when the switch is closed.
Safety pin: Makes a closed loop when the pin is inside the
clasp. This would represent a simple circuit with a closed
switch.
196
Doing the Activity
Have students break into groups of two or three students and assign them rolls of builder,
drawer, and communicator. Follow the procedure below. Each student in the group leads
where noted, but all students take part in all aspects of the activity.
Procedure
Building the
the Circuit
(Builder is team leader.)
Distribute all materials (except for switches).
1. Allow students to examine all of the materials and start experimenting without any
instruction for at least five minutes.
2. Tell students that the design challenge is to get the bulb to turn on using the materials
provided.
Note: The connection between the wire and other material has to be secure at each
contact location in order for the bulb to light. Scotch tape helps!
3. Once all groups have completed the first task, distribute the “knife” switches. Tell
students that the next task is to make the bulb turn on or off using the switch.
Identifying Symbols
(Drawer is team leader.)
1. Distribute an envelope to each group with the symbols of circuit components.
Wire
Switch (closed)
Bulb
Switch (open)
Battery
2. Allow students to identify symbols. Instruct them to arrange the symbols to represent
their circuit.
3. Tell students to individually draw a representation of their circuit using symbols.
197
Communicating Designs
(Communicator is team leader.)
1. Collect the drawings and redistribute them to other groups or have one student from
each group draw his or her diagram on the board. Explain how engineers use these
symbols to communicate their ideas to other people.
Activity FollowFollow-Up
Introduction to Principles of the Binary Number System:
1. How can you control electricity? Think back to the drawbridge example. How do you
control traffic flow over a drawbridge?
2. What if there were two lights in your circuit? How many switches would you need?
3. Explain that almost all of the electronic devices students thought of at the beginning
of class use a language called binary code. Binary code is controlling electricity flow
using switches and creating certain patterns in order to communicate information.
Group Discussion:
1. What would happen if you replaced the wire in the circuit with a rubber band? Try it.
2. Does it matter where the bulb is connected? Try different configurations.
3. How far away can a switch be from the bulb and still turn it on or off? 10 feet? On the
other side of the building?
4. Think of an example of when it is better to have a switch stay closed. Think of an
example of when it is better to have a switch stay open.
Simple Circuits in Binary Code
(Discuss after binary lesson and Binary in a Box activity.)
1. How are the two possible positions of a switch represented in binary numbers? (0 =
the switch is off; 1 = the switch is on.)
What would a circuit look like with a binary code of 001?
Conclusions
By the end of this activity, students should understand the components necessary to make
a circuit work, what role each element plays in a circuit, and how these components are
assembled. They should also be able to identify the symbols that represent different
components of the circuit and be able to draw a diagram of the circuit on paper. Students
should also know how binary code relates to circuits.
198
Vocabulary
Circuit:
A continuous loop of material that carries electric current
Voltage: The amount of electricity in a circuit
Current: How much voltage is flowing through the circuit at a time
Switch:
An element of a circuit that allows electricity to flow through the circuit or
stops the flow of electricity
References
Books
Schmidt, Victor and Verne Rockcastle. Teaching Science with Everyday Things.
Dubuque, Iowa: Kendall/Hunt Publishing Company, 2002.
Web sites
How Electricity Works: Circuits
science.howstuffworks.com/electricity4.htm
Physics Companion: Electric Current
www.dl.ket.org/physics/companion/ThePC/compan/Current/index.htm
199
By Meredith Knight, Anne Sullivan, Rachel Bill,
Geeta Pamidmukkala, Lisa Goel, and Peter Wong
Wacky
Wacky Shoes
Learning Strand:
Concepts:
Preparation Time:
30 minutes
Activity Time:
Two 45-minute classroom sessions
(Out of 5, 5 is most difficult)
2
Group Size:
3–4
Purpose
The purpose of this activity is for students to design and create a prototype of a shoe that
performs a special function. In this activity, students will…
1.
2.
3.
4.
5.
6.
Decide on a special activity that they want their shoe to do
Design the shoe
Choose appropriate materials
Build the shoe
Test the shoe
Present their design to the class, and describe one type of force on the shoe
(tension, compression, torsion)
7. Redesign if necessary
Outcomes
By the end of this activity, students will have a better understanding of the engineering
design process and of forces that act on the shoe.
Other skills practiced in this activity include group cooperation and presentation skills.
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CONNECTIONS TO THE ENGINEERING DESIGN PROCESS: In this activity
students go through all the steps of the engineering design process, just as professional
engineers do when designing something.
OVERVIEW OF THIS ACTIVITY: Students will decide on a special activity that they
would like to perform and then design a shoe to help them perform this function. They
will determine what special features the shoe will have and what materials they should
use. After designing their shoe, students will draw it and create a prototype. After the
shoes have been completed, students will test their shoes and discuss ways they could be
improved.
In this activity, students will become familiar with the engineering design process. The
steps and how they relate to this activity are as follows:
1. Identify the need or problem.
Decide on a special activity for the shoe to perform.
2. Research the need or problem.
Brainstorm possible ways to accomplish this activity with the shoe.
3. Develop possible solutions.
Sketch different designs for the shoe and think about different materials that could
be used.
4. Select the best possible solution.
Select a design for the shoe that includes all of its features and materials.
5. Construct a prototype.
Build the shoe with the materials provided.
6. Test and evaluate the solution.
Put on the shoe and try it out.
7. Communicate the solution.
Present the shoe to the class. Explain what it is designed to do and how it
accomplishes this task.
8. Redesign
Describe how the shoe could be improved.
This project also provides an opportunity for students to think about how basic forces
such as tension, compression, and torsion act on the shoe. Before the activity, review
these basic forces with students.
201
A force is any time energy is exerted on an object. It can be in the form of a push, a pull,
a twist, or a combination of all three.
Compression – when something is pressed together
Tension – when something is pulled apart
Torsion – when something is twisted
Materials
A variety of materials can be used for building
shoes. Some good examples include:
• Foam
• Cardboard
• Springs
• Suction cups (plastic shower mats work
well)
• Soda bottles
• Styrofoam
• Shoe laces
• Fabric
• Anything else kids bring from home
Doing the Activity
Divide the students into groups of three or four and outline the activity. All decisions
about the shoe must be decided as a group.
Procedure
The procedure is outlined on the attached
worksheet. Make sure to display the
materials on a table so students can
examine them. Have students plan and
sketch their designs before they start
building their shoe.
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Conclusions
By the end of this activity, students should be able to explain how they accomplished
each step in the engineering design process as outlined in the “Background for Teacher”
section. They should also be able to demonstrate and describe at least one type of force
that acts on their wacky shoe (compression, tension, or torsion).
203
STUDENT WORKSHEET
Team member names:
________________________________________
________________________________________
________________________________________
________________________________________
Engineering Application: Designing a Shoe
Step 1: Brainstorm!
Think about a unique activity where you would need a special kind of shoe. For example, you could make a
shoe that would let people walk on the ceiling, leap over tall buildings in a single bound, or walk over hot
coals without feeling anything. Be creative!!
Now, think of a name for your shoe: Shoe name:____________________________________
What is the special activity this shoe can help you do? (Wash the floor? Walk across thin ice? Write it
down.)
Special activity: _______________________________________________________________
Step 2: Think About It!
What materials should you use to have this shoe be effective? In the “Spiderman Shoe” example, the sole
would have to be able to stick to walls and support the person wearing it. Maybe it would have suction
cups. Remember, you have to be able to attach it to someone’s foot in order to test it at the end.
Write a description of your shoe’s materials below:
204
Step 3: Draw It!
Make a sketch of your design in the box below. Label the materials and the approximate measurements for
the shoe design. (Use your ruler.)
Step 4: Build It!
Use the materials you have been given, as well as any others you bring from home. Be creative, be
resourceful, and have fun.
Step 5: Test It!
Select one person to put the shoe on and walk around.
Step 6: Show It!
Get ready to present it to the class. Make sure you demonstrate one type of force (compression, tension,
torsion) when you present your shoe.
Step 7: Redesign?
What worked well? What other materials would you use? What would you do differently for the next
design?
205
By Connie Boyd, Terri Camesano, Angela Lamoureux, Hilary McCarthy,
Gissel Morales, Robin Scarrell, and Suzanne Sontgerath
Bridges Connecting Our World
‘
Materials, Tools and Machines
Engineering Design
Learning Strand:
Concepts:
Material Properties
Forces (Tension and Compression)
360 minutes (Minimum of seven
classroom sessions)
Activity Time:
Level of Difficulty: 3 (Scale of 1 – 5, with 5 as most difficult)
Group Size: Ideal group size for this project is three. Consider gender make-up of the
group.
Grade Level: 7 – 8
Cost: $20 – $30 per class of 25 students, depending on materials selected
Purpose
The purpose of this activity is to introduce students to different types of bridges, bridge
vocabulary and the forces acting upon bridges. Students will complete a hands-on activity
to reinforce the concepts of bridge design and will conduct research to see the impact of
the bridge on society.
Outcomes
By the end of this activity, the students will be able to:
1. Use appropriate bridge vocabulary;
2. Recognize types of bridges and their advantages and disadvantages;
3. Identify forces such as load, tension, and compression;
4. Develop an idea using the engineering design process;
5. Identify properties of materials; and
6. Understand the relationship between cross-section and strength of material.
Other skills practiced in this activity include logical thinking, analytical thinking,
effective communication within a team, and oral presentation skills.
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CONNECTIONS TO THE ENGINEERING DESIGN PROCESS: Students will be
given a problem and will follow all steps of the engineering design process to find a
solution.
OVERVIEW OF THIS ACTIVITY: In “Bridge Activity” students will apply their
knowledge of forces and the engineering design process to design a prototype bridge that
will fit the design criteria of various scenarios. The prototypes will be evaluated based on
whether they fit the given scenario and can withstand a certain load.
UNIT OUTLINE:
Session 1:
Session 2:
Session 3:
Session 4:
Session 5 and 6:
Session 7:
Session 8:
Introduction to Bridges
Forces Acting on Bridges
Strength of Materials
Project Introduction and Planning
Bridge Construction and Preliminary Testing
Presentation Preparation
Project Evaluation and Final Testing
This activity gives students an opportunity to become comfortable with the engineering
design process. This activity is intended to broaden students’ understanding of the
significance of bridges in the real world.
The engineering design process is a process used by all disciplines of engineering to
solve a problem. The steps of the engineering design process are as follows:
1. Identify the need or problem. The first step is to specify what problem needs
to be solved and who will benefit from this new product.
2. Research the need or problem. Engineers find out as much as they can about
current solutions available for this problem. This may involve patent research,
interviews with experts, or online research.
3. Develop possible solutions: The next step is to brainstorm possible solutions
to the problem. Solutions may be further developed through sketches and
engineering drawings.
4. Select the best possible solution. A team of engineers then reviews all
proposed solutions to determine which best solves the problem identified in
step one. (Of course, other factors, such as cost, play a role here.)
5. Construct a prototype. Next, a model of the solution is created.
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6. Test and evaluate. Engineers develop tests to evaluate whether or not the
solution will work.
7. Communicate the solution. Engineers present their solution to others. At this
stage it is important to consider what impact the new product might have on
society and what the limitations of the solutions might be.
8. Redesign. After testing the prototype and discussing the solution with others,
engineers may make improvements to the original design.
Types of Bridges
There are three main types of bridges in this activity. They are the beam bridge, the arch
bridge, and the suspension bridge. Below is a brief description of each type of bridge.
•
•
•
Beam Bridge: A beam bridge is a horizontal structure that rests on piers. One
common type of Beam Bridge is the Truss Bridge. The Truss Bridge uses
triangles to distribute the load.
Arch Bridge: An arch bridge consists of a curved structure with a stone or
concrete wall that supports one end of the bridge.
Suspension Bridge: A suspension bridge consists of a deck that is suspended
from cables. The cables pass through two main towers on the bridge and are
anchored at the ends of the bridge in anchorages. There are two main types of
suspension bridges, the standard elongated M-shape and the cable stayed Ashape.
Forces on Bridges
Several different forces act on bridges. One type of force is the load. The load is the
weight supported by the bridge. Loads can either be live loads or dead loads. The live
load is due to the cars, people, or animals crossing the bridge. The dead load is due to the
actual mass of the bridge.
All bridges experience forces. There are two main forces that act on bridges—tension and
compression. Tension is a force that acts to expand or lengthen the thing it is acting on.
Compression is a force that acts to compress or shorten the thing it is acting on.
• In a beam bridge, the top of the beam is experiencing compression, the bottom of
the beam is in tension, and the middle does not experience much of either. The
section of the truss with triangles is like the middle of the beam bridge. Thus it
does experience some compression and tension, but the majority of the forces are
on the top and bottom of the bridge.
• A suspension bridge has cables that run from between two anchorages on either
side of the bridge. These cables undergo tension as the load causes them to
stretch. The anchorage also experience tension, but it is dissipated. The deck of
the suspension bridge undergoes compression.
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•
An arch bridge is under compression. The tension force is negligible because of
the curve of the bridge. The compression force pushes outward along the curve of
the arch toward the abutments.
When engineers design, they must choose materials with appropriate properties for their
application. One very critical property of materials is the strength of a material. Some
materials can support a greater load than others. All materials fail at different points. The
yield strength of a material is defined as the minimum stress (load on the material divided
by the cross-sectional area) that causes the material to deform. The yield strength of a
material is dependent on the type of material and the cross-sectional area. The
relationship between the strength of a material and the cross sectional area is almost
always directly proportional. Therefore, if you double the cross-section of a member,
your design can withstand double the load.
Materials
•
•
•
•
•
•
•
•
•
•
•
tape
Popsicle™ sticks
bamboo skewers
spaghetti
glue or glue guns
string
ski
test fixture
weights (canned goods of various sizes work well)
bucket
2 to 4 bricks
Preparation for the Activity
Visit some of the Web sites in the References section to learn more about forces on
bridges. Collect the materials and print the worksheets. Download the “Forces Acting on
Bridges” slideshow from the STEM Teams website at www.stemteams.org.
Doing the Activity
The activity is designed to take place over the course of eight consecutive 45-minute
class periods.
209
Session 1: Introduction to Bridges
References to bridges appear in literature, music, art, and history. Share the introductory
“Bridges Connecting the World” slide show with students to help them learn about
different types of bridges and gain an appreciation for the impact of bridges in their lives.
Homework: Have students bring in a picture of a bridge, identify what type of bridge it
is, and explain why it may have been chosen for that particular location. Ask them to try
to find pictures of unusual bridges.
Session 2: Forces on Bridges
In this session, students will explore the relationship between forces and bridge structure.
Review with students the basic concept of forces. Discuss how forces act on different
types of bridges. Explain to students that the load on a bridge is the mass component of
the F = MA equation. A load can be referred to as a live load or a dead load. A live load
is the weight of whatever sits on, travels over, or hangs from a bridge. A dead load is the
weight of the bridge itself. Explain to students that there are two main forces that act on
bridges: tension and compression.
Hand out the “Tension and Compression” worksheet and give students 20 minutes to
complete it.
1. Show students the “Forces Acting on Bridges” slideshow to explain that tension is
a pulling force and compression is a pushing force.
2. Demonstrate compression and tension by setting a ski on two bridges and then
having one or more students stand on it. Explain how a bridge is similar to the ski.
The top of the bridge is pushed together due to compression and the bottom of the
bridge is pulled apart due to tension. Unlike the ski, the bridge must not bend.
Bridge designers have come up with different methods to prevent bending.
Truss Bridge: The load on a truss bridge is distributed among the members.
The top is in compression and the bottom is in tension. Sketch a truss bridge
on the board and show forces.
Arch Bridge: In an arch bridge the entire load is taken up by the arch and
carried out to the abutments. Arch bridges are always under compression.
Sketch on board
Suspension Bridge: Both tension and compression act on a suspension
bridge. The roadbed is in compression when it is carrying a load. That load is
transferred to the cables through tension. The tension is then transferred to the
210
towers as compression and the force is then dissipated into the ground. Sketch
a suspension bridge on the board.
Homework: Have students find three examples of tension and three examples of
compression at home or at school.
Session 3: Strengths of Materials
Material selection is an important part of engineering design. Engineers are concerned
with how a material reacts in certain situations. In the bridge design activity, one of the
critical properties is the strength of the material. Different materials are able to support
different amounts of weight before they will break. All materials fail at different points.
The yield strength of a material is defined as the minimum stress (load on the material
divided by the cross-sectional area) that causes the material to deform.
Have students complete the “Material Muscle” activity. This activity will introduce them
to the concept that material strength is a function of the type of material and the crosssectional area.
Session 4: Project Introduction and Planning
Divide the class into teams of three students each. Present students with the engineering
challenge. Each student team will design a truss bridge for a certain scenario. Review the
concept of the truss bridge and the strength of a triangle.
Tell students that each team of three engineers will be asked to design a bridge for a
specific purpose. Pass out the “Statement of Project” and “Project Planning” worksheets.
Assign each team one of the bridge building scenarios listed below and give them the
appropriate letter.
Bridge Building Scenarios
• A Yellow Cross supply truck must cross a fast-moving river in order to deliver
supplies to a village in Thailand. A flood has washed away the original bridge.
You must design a new bridge that can be built quickly, so the villagers will not
go hungry.
• The San Diego Zoo has just acquired a new panda. You must design a new bridge
that allows the two pandas to be together or separated depending on the
zookeepers need. Your bridge will span a rock trench that separates the two
halves of the habitat.
• Universe Studios is building a new attraction. You must design a pedestrian
walkway bridge to Gilligan’s Island. This attraction is located on an island in the
middle of a lagoon. Your bridge will serve not only as a walkway, but also as a
waiting area for those waiting to get on the ride.
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•
•
You are responsible for the stage design for a 75 Cents concert. As part of the
stage set-up you need to design a bridge that will be part of the show. Twenty
dancers will perform on the bridge.
You have been commissioned to design a bridge for a bike trail in a nature
preserve. This bridge will provide access from the mainland to an island. Only
bikes and pedestrians will be allowed on the bridge. Your bridge should not
disturb the marsh it is designed to cross.
The letters describing the above scenarios in greater detail will also the actual
dimensions.
Bridge
The Yellow Cross
San Pedro Zoo
Universe Studios
Shady Math
National Preservation
Foundation
Actual Dimensions
100 m long and 16 m wide
Model Dimensions
25 cm long and 4 cm wide
Pass out the “Grading Rubric” worksheet. Explain to students that they will be graded on
many factors including whether the bridge withstands the required load; how well the
bridge fits the given scenario; the quality of the presentation (including detailed
sketches); use of the engineering design process; and, of course, teamwork and
presentation skills. Show the students the fixture that will be used to test the bridges.
Students should be reminded of step three of the engineering design process. Students
should use the “Project Planning” worksheet to begin planning their project.
Session 5 and 6: Building the Bridges
Remind students that their engineering drawings should contain more than one view and
be clearly labeled. After the students have completed the planning phase they may
“purchase materials” by submitting a purchase order for supplies. Hand out the “Purchase
Order” worksheet. Then they should construct their bridge and test it.
Homework
Assign one or more of the following projects to students during the two bridge building
days.
1. A drawing or sketch of the bridge with at least three views and some dimensions
labeled
2. A diagram of forces acting on the bridge
3. A description of the site including environment, weather, and aesthetics
212
Session 7: Presentation Preparation
Explain to students that one of the most important steps in the engineering design process
is explaining the solution to others. Review with the students the basics of good
presentation skills. Hand out the “Presentation” worksheet.
Students will prepare a poster presentation of their bridge design. The presentation should
include the following:
1. The company name;
2. A description of how they followed the design process;
3. A detailed sketch of the bridge including a front, top, and side view and
dimensions;
4. A description of the site plan and considerations; and
5. A diagram showing the forces acting on the bridge.
Session 8: Presentation
Hang students’ posters around the room. Have students test their bridges in front of the
class.
213
STUDENT WORKSHEET
Bridge Vocabulary
Abutment: a stone or concrete wall that supports one end of a bridge
Compression: a force that acts to shorten the things it is acting on
Tension: a force that acts to lengthen the thing it is acting on
Dead load: the weight of the bridge itself
Deck: the floor of the bridge; it directly supports vehicles and
pedestrians
Live load: the weight of whatever sits on, travels over, or hangs from
the bridge
Structural members: parts of the structure
Torsion: a twisting or rotational force
Truss: an arrangement of structural members connected together to
form a ridged framework; most trusses, members are arranged to
form interconnected triangles
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STUDENT WORKSHEET
A Push and a Pull
Tension and Compression
Tension and compression are two types of forces. They are the most common forces
that act on bridges. The purpose of this activity is to gain a better understanding of these
forces and how they act on a structure such as a bridge.
Tension can be called a pulling force. Tension will often lengthen the structure it is
acting upon.
Compression can be called a pushing force. Compression will often shorten the
structure it is acting upon.
Let’s take a look at these forces in action:
Place a downhill ski on two bricks.
Have a classmate stand on the center of the ski. What happens to the ski?
Sketch below what you observe:
What happens when two classmates stand on the ski?
215
STUDENT WORKSHEET
Material Muscle Directions
Different materials are able to support different amounts of weight before they break.
Just as a stronger person can support more weight for a greater length of time, certain
materials can bear more load than others. The yield strength of a material is defined as
the minimum stress (load on the material divided by cross-sectional area) that causes a
material to deform. It depends on the type of material and the cross-sectional area.
In this experiment you will determine the load that different materials can withstand
before they break. You will share your results with the class and come up with a class
average.
Materials you will need:
Various canned goods to use as weights
A scale to weigh the canned goods
A metric ruler
Bucket
50 cm piece of string
4 15-cm material samples (a spaghetti noodle, a craft stick, a bamboo skewer,
and a straw)
Procedure:
1. Use the scale to calculate the mass of three canned goods. Record the values on
your data sheet.
2. Measure each material sample to make sure they are all 11 cm. Have two
members of your team hold the spaghetti noodle, one on each end. Drape the
string over the middle of the noodle. Have a third team member hold the bucket.
The fourth can tie the string to the bucket. Have the person holding the bucket
gradually release it so the string is taut.
3. Repeat this test for the craft sticks, the bamboo skewer, and the straw.
4. Record your results on the data sheet. Calculate the total load each material was
able to withstand and report your results to the class.
5. Record class results for each item and find the average failure load. If the noodle
doesn’t break, have one person slowly add a can to the bucket. Record the
weight at which the noodle snaps.
216
Straw
Bamboo
Skewer
Craft Stick
Spaghetti
Material
Length of
sample
(cm)
Item #1
added
(check)
Mass of Can 1_____________
Mass of item
#1 (g)
(M1)
#2 Item
added
(check)
217
Item #3
added
(check)
Mass of item
#3 (g)
(M3)
Total load to failure
(g)
(M1+M2+M3)
Mass of Can 3________________
Mass of item
#2 (g)
(M2)
Mass of Can 2______________
Mass of bucket ____________________
Material Muscle Data Sheet
STUDENT WORKSHEET
Overall neatness
Follows engineering design process
Quality of sketches
Presentation
Correct dimensions
Bridge fits scenario
Cost is equal to or below target
Bridge withstands load
Design
Accurate drawing with 3 views labeled
Complete cost analysis
Description of site
Accurate force diagram
Correct load calculation
Planning
CATEGORY
Team Name____________________________
Exceeds
Standards
(4-5)
218
Meets
Standards
(2-3)
Bridge Grading Rubric
Below
Standards
(0-1)
TOTAL
STUDENT WORKSHEET
PURCHASE ORDER
No. 1
________________________________________
Company Name
Date: _______________
Vendor:
Item
Length
Quantity
Cost per Unit
Total Cost
1
2
3
4
5
6
7
8
9
10
Total Cost:
______________________
Signature
______________________
Signature
219
_____________________
Signature
STUDENT WORKSHEET
Price List
Item
Unit
Price/Unit
Spaghetti
1
$25
Straw
1
$30
Bamboo
1
$50
Craft Stick
1
$75
Balsa Wood
25 cm x 10 cm
$200
All other items
As needed
Free
220
STUDENT WORKSHEET
Project Planning
Company name:
Describe how you followed the design process.
Sketch your bridge. Include a front, top, and side view and label the dimensions.
221
What is your total cost?
Describe your bridge site.
Draw a diagram of the forces acting on your bridge.
222
Company name:
Include the following in your presentation:
1. A description of how you followed the design process
2. A detailed sketch of the bridge including front, top, and side views
and dimensions
3. The cost of building your bridge
4. A description of your site plan
5. A diagram showing the forces acting on the bridge
223
THE YELLOW CROSS
156 Help Road
Detroit, Michigan 09326
(406) 787-5643
September 15, 2005
Dear Civil Engineers:
A week ago one of our Yellow Cross trucks was trying to deliver supplies to a village in
Thailand. Unfortunately, the river had washed away the only bridge providing access to the
village. Please design a new bridge that can be built quickly, so the villagers will not go hungry.
Thank you in advance. Below are the details:
Length
100 m
Width
16 m
Scale
4 m = 1 cm
Model Size
25 cm x 4 cm
Sincerely,
Donald Reid, CEO
Yellow Cross
224
SAN PEDRO ZOO
300 Animal Way
San Pedro, California 56123
(309) 823-0906
September 15, 2005
We have just received a panda from China. She will be in a new habitat with another panda. You
must design a bridge for the new habitat that allows two pandas to be together or separated
depending on the zookeeper’s need. Your bridge will span a rock trench that separates the two
halves of the habitat. Thank you in advance.
Bridge Length
7m
Bridge Width
2m
Model Scale
1 m = 3 cm
Model Size
21 cm x 6 cm
Sincerely,
Amanda Deering, Chief Zookeeper
San Pedro Zoo
225
UNIVERSE STUDIOS
50 Universe Street
Kissimmee, Florida 65109
(287) 361-9191
September 15, 2005
We need a bridge for a new attraction called Gilligan’s Island. The island is located in the
middle of a lagoon. The bridge will serve as a walkway and an area for those waiting to get on the
ride. Thank you in advance.
Bridge Length
20 m
Bridge Width
3m
Model Scale
1 m = 1 cm
Actual Size
20 cm x 3 cm
Sincerely,
Stacy Freeman, Attraction Manager
Universe Studios
226
SHADY MATH
55 Fifth Avenue
New York, New York 06745
(506) 956-4908
September 15, 2005
Shady Math is proud to present the 75 Cent world tour. We would like you to design a bridge
for the set. This bridge should be strong enough to hold 75 Cent and 20 dancers. Thank you in
advance.
Bridge Length
10 m
Bridge Width
4m
Scale
1 m = 2 cm
Model Size
20 cm x 8 cm
Sincerely,
Joseph Walker, Tour Manager
Shady Math
227
NATIONAL PRESERVE FOUNDATION
2 Nature Street
Miami, Florida 65189
(287) 569-4567
September 15, 2005
We would like you to design a bridge for a bike trail in our nature preserve. This bridge will
provide access from the mainland to beaches on the island. It should be strong enough to hold
bikes and pedestrians. Also, it must not disturb the natural marsh. Thank you in advance.
Bridge Length
50 m
Bridge Width
8m
Bridge Scale
2 m = 1 cm
Model Size
25 cm x 4 cm
Sincerely,
Dan Steel, Chairman
National Preserve Foundation
228
Conclusions
By the end of this activity students should:
1. identify all steps of the engineering design process;
2. be able to use the engineering design process to create a prototype;
3. recognize the main types of bridges;
4. identify the major forces acting on bridges;
5. be able to explain how the forces of tension and compression act on different
types of bridges; and
6. understand the concept of strength of materials and the relationship between
material strength and cross-sectional area.
Vocabulary
engineering design process: the process used by engineers to develop a design
beam bridge: a horizontal structure resting on piers
truss bridge: a type of beam bridge in which members are connected in a triangular
pattern to distribute the weight
arch bridge: a curved structure with a stone or concrete wall that supports one end of a
bridge
suspension bridge: a bridge that experiences mostly compression; forces due to tension
are negligible due to the curve of the bridge
load: weight supported by an object
live load: the weight of whatever sits on, travels over, or hangs from a structure
dead load: the weight of the bridge itself
deck: the floor of the bridge; directly supports the live load, such as pedestrians or
vehicles.
cable: a strong, usually large diameter, steel or fiber rope used in supporting suspension
bridges
pier: a support structure at the junction of connecting spans of bridges
anchorage: a structure located at the ends of the suspension bridge which serves as an
anchor for the cables.
tension: a force that acts to expand or lengthen the thing it is acting on
compression: a force that acts to compress or shorten the thing it is acting on
abutment: a stone or concrete wall that supports one end of a bridge
yield strength: the minimum stress (load on the material divided by cross-sectional area)
which causes the material to deform
cross-sectional area: area determined by a plane cut through an object
structural members: a part of the structure that carries the load
torsion: a twisting force
truss: an arrangement of structural members connected together to form a rigid
framework
229
References
Building Big Educators’ Guide
www.pbs.org/wgbh/buildingbig/educator/index.html
Extensions
•
To add more math to the activity, provide students with two out of the three variables
and have them calculate the third.
•
Have students calculate the costs associated with building their bridges. Assign a
target cost to each scenario and have the students stay within budget while
completing their prototype.
230
By Connie Boyd, Terri Camesano, Emine Cagine, Angela Lamoureux,
Hilary McCarthy, Robin Scarrell, Suzanne Sontgerath, Katherine Youmans
Broken Bones
Materials, tools, and machines
Bioengineering technologies
Learning Strand:
Concepts:
Material properties
Engineering design process
Preparation Time:
60 minutes (after materials have
been collected)
Activity Time:
Minimum of six classroom sessions
300 minutes
Level of Difficulty: 2 (Scale of 1–5, with 5 as most difficult)
Group Size: 4–5 students per group (consider forming all-female groups to boost girls’
confidence)
Grade Level: 7–8
Cost: The cost of the activity is less than $20 per class.
Purpose
The purpose of this activity is to introduce students to the concepts of the engineering
design process and to teach them how to apply those concepts to an actual design. In
“Broken Bones,” students will:
1.
2.
3.
4.
5.
6.
7.
Learn about different engineering disciplines;
Use the engineering design process to solve a specific design task;
Learn how to evaluate and choose materials based on material properties;
Explore the concept of a prototype;
Sketch and build a prototype of their design;
Explore the field of biomedical engineering; and
Develop methods for communicating their design solutions to a larger group.
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Outcomes
1.
2.
3.
4.
Understand all steps of the engineering design process;
Follow the engineering design process to create a prototype;
Choose materials based on material properties; and
Draw and label a prototype design including a cross-section.
Other skills practiced in this activity include logical thinking, analytical thinking,
effective communication within a team, and oral presentation skills.
CONNECTION TO THE ENGINEERING DESIGN PROCESS: This activity is
designed to be a comprehensive review of the engineering design process. It will cover
all steps of the process. By the end of this activity, students will be able to apply the
engineering design process to any engineering problem.
OVERVIEW OF THIS ACTIVITY: In “Broken Bones,” students will explore the steps
of the engineering design process. They will first receive some background instruction
about biomedical engineering or bioengineering. Then they will learn about material
selection and material properties by using a guide created for them. Students will then
break into small groups and brainstorm. Each student group is assigned a specific design
problem. Students will be given materials and asked to create a prototype. Finally
students will communicate their solution through a poster presentation.
UNIT OUTLINE:
Session 1:
Introduction
Session 2:
Identify the need and research the problem
Session 3:
Develop possible solutions and select the best solution
Session 4/5*: Construct a prototype
Session 5/6*: Construct a prototype, test, evaluate the solution, and begin posters
Session 7:
Communicate the solution and redesign
Engineers use science and math to solve problems. The engineering approach to solving
problems can be broken down into several steps called the engineering design process.
The design process can be applied to designing anything from a CD player to a band-aid.
In “Broken Bones,” students will use the design process to redesign a cast. They will
develop several possible solutions to their problem, select the best one, and build a
prototype. By developing test methods for their design, students will learn that all
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products designed by engineers must be tested frequently before they are ready for largescale production. Finally, students will create a poster to share their design with their
classmates.
The engineering design process is a process used by all disciplines of engineering to
solve a problem. The steps of the engineering design process are as follows:
1. Identify the need or problem. The first step is to specify what problem needs
to be solved and who will benefit from this new product.
2. Research the need or problem. Engineers find out as much as they can about
current solutions available for this problem. This may involve patent research,
interviews with experts, or online research.
3. Develop possible solutions. The next step is to brainstorm possible solutions
to the problem. Solutions may be further developed through sketches and
engineering drawings.
4. Select the best possible solution. A team of engineers then reviews all
proposed solutions to determine which best solves the problem identified in
step one. (Of course, other factors, such as cost, play a role here.)
5. Construct a prototype. Next, a model of the solution is created.
6. Test and evaluate. Engineers develop tests to evaluate whether or not the
solution will work.
7. Communicate the solution. Engineers present their solution to others. At this
stage it is important to consider what impact the new product might have on
society and what the limitations of the solutions might be.
8. Redesign. After testing the prototype and discussing the solution with others,
engineers may make improvements to the original design.
What is Biomedical Engineering or Bioengineering?
Biomedical engineers (also called bioengineers) use their knowledge of science and math
to help solve health problems. Biomedical engineers develop materials, processes, and
devices that help prevent or treat disease or rehabilitate patients. According to the
Biomedical Engineering Society, the areas of specialization for biomedical engineers
include biomaterials; bioinstrumentation; biomechanics; medical imaging; rehabilitation;
and cellular, tissue, and genetic engineering.
Biomedical engineers who specialize in biomaterials develop materials that can be safely
implanted in the body. Engineers who work in biomechanics apply principles from
physics to biological systems. They develop artificial organs, such as the artificial heart.
Engineers who focus on bioinstrumentation use computers or other electronic devices to
diagnose or treat disease. A rehabilitation engineer helps improve the quality of life for
people with disabilities. Tissue and cellular engineers grow cells outside of the body to be
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implanted in the body and serve some function. Genetic engineering is a related
discipline in which an organism’s DNA is altered so that different proteins will be
produced. Genetic engineering has many applications in drug production.
For more information regarding the specialties within bioengineering, please see the
“Introduction to Biomedical Engineering” worksheet.
What are Material Properties?
The proper selection of materials is critical in all areas of engineering design. All
materials have different properties that may or may not make them suitable for a given
application. Materials come from natural resources. They are made up of the elements
found on the periodic table. They may be elements in their pure form or a combination of
elements. Materials are often processed to give them different properties. Some different
types of materials include metals, plastics, composites, ceramics, and textiles. The
properties of these materials are usually divided into three different categories: physical
properties, mechanical properties, and chemical properties. Physical properties include
color, density, melting point, and water absorption rate. Mechanical properties include
strength, ductility, and rigidity. Chemical properties include the composition of the
material or the corrosion resistance of the material. To select the proper materials for an
application, an engineer must first determine the properties that are important for her
design. Once this determination has been made she can then research specific materials
which may have the necessary properties.
For more information on materials see the handout “Material Properties.”
Materials
Per group
• boxes to hold recyclable materials
• half can of Play-Doh™
• 4 Popsicle™ sticks
• 6 to 8 recyclable materials: fabric, cotton batting, egg cartons, toilet paper or
paper towel rolls, toothpicks, plastic bottles, milk cartons cut in pieces, rubber
bands, straws, plastic tubing
• poster board
• markers
• digital scale
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Doing the Activity
“Broken Bones” is designed to take place over the course of six consecutive 45-minute
class periods. This activity will be used in conjunction with the life sciences portion of
the curriculum. A background discussion on the skeletal system and its function is
necessary. Students should have some background on how bones break and heal.
Session 1: Introduction
Part 1: Introduction to Biomedical Engineering
Explain to the students that there are many engineering disciplines. One of these
disciplines is biomedical engineering or bioengineering. Biomedical engineers use their
knowledge of math and science to solve health problems. Within the field of biomedical
engineering there are many specialties. Using the “Introduction to Biomedical
Engineering” handout as a guide, give students some background information on the
types of problems biomedical engineers help solve.
Part 2: Review the Engineering Design Process
All engineers follow a series of problem-solving steps called the engineering design
process. This process consists of the following eight steps:
1. Identify the need or problem
2. Research the problem
3. Develop possible solutions
4. Select the best possible solution
5. Construct a prototype
6. Test and evaluate
7. Communicate the solution
8. Redesign
Pass out the “Engineering Design Process” handout. Explain to students that they will be
redesigning a cast. Review the design process with students. Encourage them to relate
this process to their project.
Part 3: Review Material Properties
The selection of the proper materials is a key factor in solving an engineering design
problem. All materials have different properties and geometries that may or may not
make them suitable for a given application. Using the “Material Properties” handout as a
guide, discuss with students different properties of materials such as strength, flexibility,
hardness, mass, and density. Use examples readily available, such as modeling clay,
spaghetti, Popsicle™ sticks, and paperclips to demonstrate some of the different material
properties.
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Homework Assignment: Jig Saw Puzzle
Assign students to groups of four or five. Give each group four or five articles to read for
homework. The next day, have students share a summary of their assigned article with
their group.
Session 2: Research the Problem
Note: Before beginning this phase of the activity, break students into groups of five.
Students have completed step one of the design process. They have identified the need or
problem, which is to redesign a cast. In this session, students will work on step two of the
design process by researching the problem.
Based on their homework assignment, students will have read articles on the current
types of casts that are available and what the issues or problems are with each one. Have
all students report to the class on their articles.
Session 3: Developing Solutions
In this session, students will work on developing solutions to their problem. First explain
to the students that engineers work on developing solutions using a technique called
brainstorming. Brainstorming involves thinking of as many possible solutions to a
problem as possible in a short period of time. All members of the team contribute, and all
ideas are equally valid at this point.
Classroom Exercise: Brainstorming
Part 1: Identify the problem. Have students work in groups on a generic problem. One
example is “How can you open a Ziploc™ bag without using your hands?” Have each
group share its best solution with the class. (15–20 minutes)
Part 2: Develop possible solutions. Present each group with the “Letter from Student”
and “Design Activity” handouts and a box of materials. Each team will be required to
construct a prototype that has a mass of less than 300 grams. Allow groups to brainstorm
ideas for 20–25 minutes. Emphasize that in addition to solving the problem the student’s
design must be stable enough to hold the “broken bone” in place. Remind students that
the materials in the box may represent any materials they would like, even ones that have
not been developed yet. Students should be prepared to describe the properties of the
materials they choose for their cast. In addition, each group may bring in one material
from home.
Note: Bring in a digital scale so students can determine the mass of their individual
materials before they choose a design.
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Part 3: Select the best solution. Allow students to pick their best solution. Review the
prototype for feasibility.
Sessions 4 and 5: Construct the Prototype
and Test and Evaluate Solutions
Time Required: 45–60 minutes
In this session students will construct a prototype and test and evaluate it. Emphasize that
a prototype is a model of what the final product might look like and is often smaller than
the original. Once the prototype is complete, students should spend some time thinking of
methods for testing and evaluating their design.
Construct the Prototype: Students should use the materials provided and their sketches
to construct a prototype cast. The picture below shows an example of a cast created by
Worcester Public School students.
Prototype Cast for Broken Bones Activity
Test and Evaluate the Solutions: Since the materials the students are using could
feasibly represent any materials, the only physical test to determine whether or not the
project is successful is measuring the mass of the students’ design. Allow students to use
the digital scale to calculate the mass of their design. Students’ designs should be
evaluated on their stability. Do they bend or move from side to side? Do they solve the
problem given? In addition, students should design a test for their prototype that proves
whether or not their problem has been solved.
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Sessions 5 and 6: Communicate the Solution and Redesign
A very important part of an engineer’s job is the ability to communicate ideas and
solutions to a larger audience. Communicating the solution is step seven of the
engineering design process. This communication may be with co-workers, superiors, or
even customers. In this section of the activity, students will have the opportunity to
communicate their solutions through a poster presentation. This is an important step in
the process because it gives the students an opportunity to clearly articulate their design
concepts. Remind students that good presentation skills are very necessary for a wide
variety of professions. Finally, individual teachers may decide whether they would like to
give students the opportunity to redesign their casts based on feedback from the class.
Poster Presentation Development: Hand out the “Broken Bones Presentation Poster
Content” worksheet. Students should create a poster that clearly explains their design.
Posters should be neatly done and contain all required information. Students should be
prepared to speak for 3–5 minutes on their design process and results. Classmates should
be encouraged to ask questions.
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STUDENT WORKSHEET
Worksheet 1: Introduction to Biomedical Engineering
Biomedical engineers (also called bioengineers) use their knowledge of math and science
to solve health problems. Biomedical engineers develop materials, implants, and devices
for the treatment of disease and rehabilitation. Biomedical engineers specialize in
biomaterials; bioinstrumentation; biomechanics; medical imaging; rehabilitation; and
cellular, tissue, and genetic engineering.
Biomaterials
Biomedical engineers who specialize in biomaterials develop materials that can be
safely placed in the human body. Medical devices that are placed in the body are called
implants. Examples of implants include contact lenses, catheters, artificial heart valves,
and joint prostheses. The biomaterial specialist has to make sure that a material provides
the necessary biological function and is non-toxic, not degraded over time, strong enough
to absorb stress, resistant to infection, and does not allow protein buildup that causes
blood clots. Although these biomaterials can be made from many different substances,
polymer blends, metal alloys, and ceramics are most common.
The second type of biomaterial refers to materials that scientists and engineers
develop to mimic diseased or damaged bodily components, such as artificial skin, blood,
and cartilage. A team from the University of Illinois developed a plastic material that is
being examined for its use as artificial skin in the creation of organs. Just like real skin,
this substance can bleed and heal itself. Some forms of artificial skin are already
available commercially and are used to provide skin replacement for burn victims. They
are also used as temporary patches that prevent infection while allowing a patient’s skin
grafts to heal during the treatment of severe burns.
Bioinstrumentation
A biomedical engineer involved in bioinstrumentation uses computers or other
electronic devices to either diagnose or treat disease. A person employed in this field
might develop monitoring devices such as an electrocardiograph (a device that records
heart activity) or a sleep apnea monitor (a device that records pauses in breathing), or
they may develop software that helps to analyze the signals from such devices.
Biomechanics
The field of biomechanics applies physics to biological systems. Artificial organs,
such as an artificial heart, are designed and improved by biomedical engineers who
specialize in biomechanics. Biomedical engineers from ABIOMED have created an
artificial heart. Although the artificial heart is only being used in clinical trials on very ill
patients, researchers hope that patients can live an extra two years with the device.
Another example of a biomechanical project is conducting stress and strain tests
on ligaments and cartilage tissue. Many people are familiar with anterior cruciate
ligament (ACL) injuries and know someone who has needed knee surgery. By studying
the differences between ACL deficient tissue and the healthy knee, researchers can help
rehabilitate patients faster.
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Medical Imaging
Medical imaging involves the use of different types of waves (ultrasound,
magnetic, and X-rays) to create an image of the body. Engineers are trying to create
sharper and more accurate images while minimizing discomfort to the patient. Currently,
the best way to detect for colon cancer is to use an invasive procedure known as a
colonoscopy in which a patient under anesthesia has a long flexible tube with a light and
a tiny camera “look” inside his or her large intestine. However, research is underway to
create a virtual colonoscopy, in which a patient’s colon could be imaged through the skin.
Researchers at Wake Forest University are working on this painless and non-invasive
method.
Rehabilitation Engineering
The job of a rehabilitation engineer is
to improve the quality of life of people
with disabilities. For example,
rehabilitation engineers have designed
the iBOTTM Mobility System, a
sophisticated wheelchair that can
tackle stairs, rough terrain, and even
lift the patient to be eye-level with
standing adults. The iBOT was created
by Worcester Polytechnic Institute
alum Dean Kamen, who also invented
the Segway scooter.
Dean Kamen and the iBOT
Another product designed by rehabilitation engineers is the Smartphone for
cognitively-impaired elderly persons. This phone is currently being developed by
researchers at the University of Florida. The Smartphone sends reminders for taking
medication, turns appliances on and off, checks remotely if doors are locked, provides
directions outside the home, and signals for help when needed.
Cellular, Tissue, and Genetic Engineering
Tissue and cellular engineers grow cells outside of the body, often with the
intention of later implanting them in the body. The goal of a tissue or cellular engineering
project could be to create a biomaterial, such as skin. Skin can be grown in a laboratory
setting by tissue engineers and later used to treat severe burns.
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Professor George Pins and Ph.D.
student Brett Downing from
Worcester Polytechnic Institute are
building skin substitutes that can heal
and regenerate. Besides helping burn
victims, this work can benefit
diabetics by preventing amputations
for foot ulcers that do not heal.
Professor George Pins and Ph.D. student Brett Downing
Genetic engineering is a related discipline, in which an organism’s DNA is altered
to produce different proteins. Genetic engineering has many applications in drug
production. For example, some of the proteins that are used in pharmaceutical products
are expensive or impossible to manufacture chemically. Living cells, including bacteria,
yeasts, plants, and animal cells, can often be grown in a laboratory setting. These living
cells can be used as factories to produce important therapeutic proteins. Sometimes the
amount of protein that the cell naturally produces is so small that the process becomes
expensive. Genetic engineering can be used to increase production of a desired protein or
to make the process occur faster or cost less. Professor Susan Roberts from the University
of Massachusetts Amherst is using genetically-engineered plant cells to maximize the
production of the breast cancer drug paclitaxel. Taxus cells already produce taxol under
certain growth conditions, but genetic engineering allows more of the protein to be
produced.
In other cases, the genes that code for the production of a therapeutic protein can
be inserted into a bacterium or other microorganism. Microorganisms are much easier
and cheaper to work with in a laboratory than plant or animal cells. For example,
microorganisms in baker’s yeast are used to produce the protein in the Hepatitis B
vaccine, which is now widely available in the United States.
For more information about biomedical engineering, visit the Biomedical
Engineering Society website at www.bmes.org/links.asp.
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STUDENT WORKSHEET
Worksheet 2: Material Properties
For engineers, choosing materials is an important step in the design process. All materials
have different properties that may or may not make them suitable for a given application.
This handout is designed to give you some background on different types of materials
and material properties.
What are Materials?
Materials come from nature. They are made up of the elements found on the periodic
table. They may be elements in their pure form or a combination of elements. Materials
are often processed to make them have different properties. For example, trees are found
in nature and processed to make paper, petroleum is made into plastic, and cotton is made
into clothes.
What are Some Types of Materials?
Metals
Metals are elements with a valence number of 1, 2, or 3 on the periodic table. Metals are
typically chosen for their strength and their ability to be formed into practical shapes.
Metals are also good conductors of electricity. One of the drawbacks associated with
metals is their density. They are much denser than other materials. Metals tend to be
stronger and more rigid than other materials, such as polymers. They are often combined
with other elements to form an alloy. When alloys are formed, they exhibit different
properties than the original elements. Alloys may be lighter in weight, stronger, or more
flexible than the original elements. An example of an alloy is brass, which is made up of
zinc and copper. Another alloy that we often refer to as a metal is steel. Steel is a
combination of iron and other elements, such as carbon.
Some examples of metals: gold, iron, silver, titanium, aluminum, tungsten, platinum, and
copper
Plastics
Plastics are technically polymers. They are made of many small molecules that are
connected together in long chains. Polymers contain repeating elements, and each
element will contain many carbon atoms and other nonmetallic elements, such as
hydrogen. Polymers can be made by people, but some are naturally occurring and
produced by plants or other kinds of living creatures. Polymers have some special
characteristics which make them very useful in certain applications. They can be resistant
to chemicals, insulate against both heat and electricity, are usually lightweight, and can
be formed into many different shapes. Elastomers, such as rubber, are a group of plastics
that return to their original shape after stress. We come into contact with polymeric
materials hundreds of times each day. From the glue on the back of Post-it® Notes, to
clothing, to Tupperware™, polymers are all around us.
Some examples of plastics: polystyrene, polyvinyl chloride, polyester, and nylon
242
Composites
A composite is a combination of two or more materials. When combined, the materials
have improved properties. Plywood is an example of a composite made up of cellulose
fibers from trees and glue. Composite materials are found in skis, boats, bike helmets,
and tennis rackets.
Ceramics
Ceramics are a combination of one or more metals with a non-metallic element.
Ceramics are made with a high temperature heat treatment. (Think of clay being fired in a
kiln to make pottery.) Ceramics are strong but lighter in weight than metals. They do not
rust. Ceramics can be used as electrical insulators, lubricants, and in many other areas.
Textiles
Textiles are fabrics consisting of fibers of other materials. These fibers can be either
natural fibers such as cotton, wool, cashmere, and silk or synthetic fibers such as nylon,
acetate, and polyester. Textiles may also be a combination of man-made and natural
fibers.
What are Material Properties?
Physical Properties
Physical properties describe how a material interacts with different forms of energy.
Some examples of physical properties are color, density, melting point, or water
absorption.
Mechanical Properties
A mechanical property is the reaction of a material when a force is applied to it. Some
examples of mechanical properties include strength, flexibility, and rigidity.
Chemical Properties
Chemical properties describe the make-up of the material, such as what elements it
contains. For example, the chemical nature of water is that each molecule contains two
hydrogen atoms and one oxygen atom. Some examples of chemical properties include
composition (what the material is made of) and corrosion resistance (the material’s ability
to resist deterioration).
Engineers use many different resources to find the different properties of materials. These
include textbooks, handbooks, websites, and performing experiments on the materials.
One website with many different material properties is www.matweb.com.
Which Material is Best for the Job?
In order to choose materials for a particular design, you must decide which properties are
important to solve your particular problem. Ask yourself some of the following questions.
•
Is the weight of my design important? Consider the density of the materials you
are using.
243
•
Is the strength of my design important? Consider the strength of the materials you
are using.
•
Should my design be stiff or should it have some flexibility? Consider the rigidity
of the material.
•
Does my design need to withstand heat? Consider the melting point of the
materials you are using.
•
Does my design need to be water resistant? Consider the water absorption rate of
the material.
One other factor that engineers must consider during the material selection process is the
cost of the material. Although a material may have exactly the right properties, if it is too
expensive a cheaper alternative will be used instead.
244
Materials at Work
Kevlar®
A composite material developed by Stephanie Kwolek, an engineer at Dupont, Kevlar is
five times stronger than the same weight of steel and is corrosion-resistant. It can be
found in bulletproof vests, skis, space vehicles and boats.
Gore-Tex®
A lightweight, breathable fabric with an ultra-thin, waterproof layer, Gore-Tex is used to
make comfortable, waterproof jackets.
PhotoLink®
A coating for medical devices developed by Surmodics, PhotoLink reduces water
absorption and has anti-bacterial properties.
245
Resources
Books
Knapp, Brian. Science in Our World: Materials. Danbury, CT: Grolier Educational
Corp., 1994.
Morgan, Sally and Adrian Morgan. Designs in Science: Materials. New York, NY: Facts
on File, 1994.
Websites
Exploring the Material World: Three Classroom Teaching Modules
www.lbl.gov/MicroWorlds/module_index.html
It’s a Materials World
www.mse.vt.edu/academics/news/MW_v1n1.pdf
Materials by Design
www.mse.cornell.edu/courses/engri111/index.htm
Materials Science and Engineering
www.crc4mse.org/MEL/BIKE/Index.html
Profiles of Materials Scientists and Engineers
www.careercornerstone.org/matscieng/profiles/aboud
Stephanie Kwolek
web.mit.edu/invent/www/ima/kwolek_intro.htm
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Step 6:
Evaluate the
solution
Step 1:
Identify
the problem
Step 5:
Construct a
prototype247
Step 7:
Share
the solution
Step 8:
Redesign
Step 4:
Select a
solution
Step 3:
Develop
solutions
Step 2:
Research
the
problem
STUDENT WORKSHEET
Cast Design
Name …………………………………………………Date……………………………………
1. What is the problem you are trying to solve?
2. What materials does your box contain?
3. What were the results of your brainstorming session? What are possible
solutions to your problem?
4. What is the best solution for your problem? Describe your prototype.
5. Draw a sketch of your prototype on the back of this page. Include a front,
top, and side view.
248
6. What materials do your recyclable materials represent?
7. Why did you choose these materials? What properties must the materials in
your prototype exhibit (i.e., strength, flexibility, softness, permeability,
absorption rate)?
8. How would you test and evaluate your prototype?
9. Describe a test that could be used to determine if you have solved your
original problem.
10. How would you redesign your cast if you had more materials and time?
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250
STUDENT WORKSHEET
Poster Session
Scientists and engineers often share their ideas with posters. You and
your teammates will be designing a poster to explain your cast
design to other members of your class. Include the following topics
on your poster:
• The engineering design process
• The problem your group was trying to solve
• Any preliminary sketches you have made as well as your final
design
• A description of your prototype
• A list of materials used
• A description of what properties the materials have (e.g.,
weight, flexibility, or strength)
• The percentage lighter your prototype is than the original
• Examples of how you evaluated your design to determine if it
works
• An analysis of whether the new design solves the original
problem
• A description of how you would improve your prototype if given
time for a redesign
251
Conclusions
By the end of this activity the students should be able to
1. Identify all steps of the engineering design process;
2. Create a prototype;
3. Select materials based on material properties;
4. Draw and label a prototype design including a cross-sectional view;
5. Prepare a presentation; and
6. Work effectively in teams.
Vocabulary
engineering design process: the process used by engineers to develop an idea or design
bioengineering: a discipline of engineering that applies math and science to health
problems
biomedical engineering: see “bioengineering”
prototype: a model or actual working version of a design concept
brainstorming: a technique used to generate ideas wherein a group rapidly generates
ideas that will later be analyzed and discussed
material properties: factors that describe a material and how it will behave under certain
conditions
biomaterials: materials that can be safely implanted in the human body
biomechanics: applies physics to biological systems
rehabilitation engineer: an engineer who improves the quality of life of people with
disabilities
tissue or cellular engineer: an engineer who develops cells outside of the body
genetic engineering: a bioengineering discipline in which an organism’s DNA is altered
so that different proteins will be produced
plastics: polymers (many small molecules connected together in long chains)
ceramics: a combination of one or more metals with a non-metallic element
physical properties: properties that describe how a material interacts with different
forms of energy
mechanical properties: properties determined by the reaction of a material when a force
is applied to it
chemical properties: properties that describe the make-up of the material, such as what
elements it contains
Extensions
•
•
Have students create full-size prototypes.
Have students create presentations using Powerpoint or other presentation
software.
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By Karen Spaulding, Erica Thrall, Jessica Louie,
Olga Nikolayeva, Megan Lopes, and Anna Swan
Making Bacteria Glow: Genetics, DNA, and the Engineering of
Traits
Learning Strand:
Bio-related technologies
Concepts:
Engineering design process
Genetics
DNA structure and function
Preparation Time:
See chart below.
Unit Time:
Time Required – 2 weeks.
See chart below.
Class
Period
1–2
3–5
6
7
8
9–11
Activity
Genscope
DNA Lego
Transformation and
Genetic Engineering
RNA Bingo
Video on Human
Genome
pGLO Lab
Preparation
Time
10 min.
20 min.
10 min.
Activity
Time
90 min.
135 min.
45 min.
10 min.
10 min.
45 min.
45 min.
40 min.
135 min.
Level of Difficulty: 5
Group Size: groups of 4
Purpose
The purpose of this unit is to introduce students to genetic engineering. In “Glowing
Bacteria,” students will:
1. Become familiar with the structure of DNA;
2. Learn about genetic transformation; and
3. Genetically engineer bacteria to make it glow green.
253
Outcomes
By the end of this unit, students will be able to:
1.
2.
3.
4.
Describe the structure and function of a DNA molecule;
Explain the process of DNA replication;
Model translation and protein synthesis; and
Determine which amino acids are represented by a series of codons.
Other skills practiced in this unit include logical thinking, analytical thinking, and
effective communication.
There are eight steps in the engineering design process as described by the Massachusetts
Department of Education Science and Technology Engineering Curriculum Framework:
1.
2.
3.
4.
5.
6.
7.
8.
Test and evaluate
Redesign
In this unit, students will apply step 6 of the engineering design process; they will test
and evaluate the transformation of the Green Fluorescent Protein gene into E. coli
bacteria.
OVERVIEW OF THIS UNIT: In “Making Bacteria Glow,” students will use
Genscope, a genetics computer simulation, to study traits and the frequency of gene
expression, model the structure of DNA with DNA Legos, and explore genetic
transformation with the pGLO lab from BioRad.
254
Kids know that traits, such as brown eyes or curly hair, are passed from parents to
offspring, but they may not understand how this process occurs. This lesson will
introduce them to DNA – its structure, replication, and role in heredity.
To begin the lesson, you may want to review with students the structure of a cell.
Remind them that both plant and animal cells contain a nucleus, yet the cells of other
organisms, such as bacteria, do not. The nucleus of plant and animal cells contains
chromosomes, and the chromosomes contain segments of deoxyribose nucleic acid
(DNA) called genes. Genes determine traits. In the case of bacteria, there are rings of
DNA (or plasmids) in the cell that contain the genetic information.
Structure of DNA
The structure of DNA can be thought of as a twisted ladder. This shape is referred
to as a “double helix.” DNA is made of repeating units called nucleotides. Each
nucleotide contains a phosphate group, a sugar, and a nitrogen base. The backbone of the
DNA molecule is made up of phosphate and sugar molecules. Attached to this backbone
are nitrogen bases. Complementary base pairs connect and form the rungs of the ladder.
Adenine pairs with thymine, cytosine with guanine.
Replication
DNA copies itself through a process called replication. The double-stranded DNA
molecule untwists and unzips down the middle. The complementary base pairs separate.
Each strand of the DNA molecule serves as a template for a new strand. Complementary
bases pair up to match the original strand. In this way, a new strand of DNA is made. The
new strand zips and twists with the old strand. Occasionally, a mistake is made in this
process. The wrong base pair attaches. This could lead to a genetic mutation (more about
this later).
DNA is the blueprint. DNA carries information about whether eyes will be blue or
brown, whether an individual will have a deep voice or a high-pitched one, whether he or
she will be better at running short distances or long. How does this blueprint get read and
used to form the person?
Transcription
DNA codes for RNA which codes for proteins. During transcription, DNA is
copied to form messenger ribonucleic acid (mRNA). As in replication, the DNA locally
unwinds, and complementary base pairs line up. The only difference is that RNA uses
uracil as a complement to adenine instead of thymine. The mRNA carries the genetic
information from the nucleus to a ribosome.
Translation
Next the genetic information is used to make a sequence of amino acids. A chain
of amino acids is a protein. Proteins make up nearly every part of the human body
including hair, skin, and muscle tissue, as well as enzymes that catalyze reactions. To
255
read the genetic code from the mRNA molecule and use it to choose the right amino acids
to make a specific type of protein, the transfer ribonucleic acid (tRNA) gets involved.
A tRNA molecule has a loop containing three nucleotides called the anticodon.
The anticodon is complementary to the mRNA. The job of the tRNA is to recognize the
codon on the mRNA and pick up the correct amino acid. A tRNA molecule with a
particular anticodon attaches only to a specific amino acid.
The goal of the whole process of replication, transcription, and translation is to
produce proteins that are described in the genetic code of DNA.
Codon Table
How does the tRNA molecule know which amino acids to grab? The bases in an
mRNA codon code for a certain kind of amino acid. Follow the table below to see which
codons code for which amino acid. The “First Base” is the first base in the mRNA codon.
Note that there is some redundancy. UUU and UUC both code for phenylalanine.
However, there is no ambiguity. UUU will never represent anything but phenylalanine.
Second Base
U
C
A
G
UUU PhenylUUC alanine
UCU Serine
UCC
UCA
UCG
UAU Tyrosine
UAC
UGU Cysteine
UGC
UAA Stop codon
UAG Stop codon
UGA Stop codon
UGG Tryptophan
CGU Arginine
CGC
CGA
CGG
First Base
UUA Leucine
UUG
C
A
G
CUU Leucine
CUC
CUA
CUG
CCU Proline
CCC
CCA
CCG
CAU Histidine
CAC
AUU Isoleucine
AUC
AUA
ACU Threonine
ACC
ACA
ACG
AAU Asparagine
AAC
AGU Serine
AGC
AAA Lysine
AAG
AGA Arginine
AGG
GCU Alanine
GCC
GCA
GCG
GAU Aspartic
GAC acid
GGU Glycine
GGC
GGA
GGG
AUG Methionine
start codon
GUU Valine
GUC
GUA
GUG
CAA Glutamine
CAG
GAA Glutamic
GAG acid
U
C
A
G
U
C
A
G
U
C
A
G
U
C
A
G
Table from Freeman, Scott, Biological Science, Upper Saddle River, New Jersey: Prentice Hall, 2002.
256
Third Base
U
Mutations and Evolution
Students are probably familiar with the movie X-Men. In the movie, humans with
genetic mutations such as a snake-like tongue have special powers. Of course, the
mutations shown in the movie are unrealistic, but the idea of mutation is a very important
one in biology; it is the cornerstone for evolution.
Mutations occur when there are base-pair substitutions or base-pair insertions or
deletions. Sometimes the wrong base pairs get matched up. Often, due to redundancy,
this has no effect. Or there may be only a slight difference in the protein created.
Sometimes there is a noticeable effect. In the case of an adverse effect, the living
thing may die before it reproduces, and the mutation will be wiped out. Or it may
reproduce and spread this adverse effect to its offspring. In the case of a beneficial effect,
the offspring will prosper, and eventually, over millions of years, this mutation will
become widespread in the population. This is how living things evolve.
The Human Genome Project
Humans have 23 pairs of chromosomes. The word “genome” refers to all the
genes. Students may have heard of the Human Genome Project. The goal of this project
was to figure out the role of all human genes, no small task considering that the human
genome contains more than 3 billion base pairs.
Genetic Engineering
In this activity, students will be introduced to genetic engineering, or changing the
genome of an organism by tinkering with its DNA. The pGLO activity uses recombinant
DNA techniques to move genes that code for a specific trait from one organism to
another. This is called genetic transformation.
Genetic transformation has many uses. Gene therapy is an example of how
genetic transformation is used to help people. The goal is to replace defective genes with
normal ones to help patients with diseases such as sickle-cell anemia, cystic fibrosis, and
Huntington’s disease. Scientists are still working on developing this technique.
Genetic transformation is also used in agriculture. Genetically modified crops
have natural insecticides, natural resistance to herbicides, or other improvements, such as
soybeans with a higher percentage of unsaturated fatty acids.
Another use for genetic transformation is bioremediation. Bacteria can be
transformed so that they are capable of digesting oil spills.
Genetic Transformation in the pGLO™ Lab1
In the pGLO Lab, students insert a gene from bioluminescent jellyfish into
bacteria. The gene codes for Green Fluorescent Protein (GFP). When the bacteria
produce GFP, they glow green under ultraviolet light.
Students will work with a bacterial plasmid, or a small, circular piece of DNA.
This plasmid contains the gene for GFP as well as a gene for resistance to ampicillin.
When the sugar arabinose is added to the cell’s nutrient medium, the gene for GFP is
switched on. The cells that have transformed are white on plates without arabinose and
fluorescent green on plates with arabinose.
1
The pGLO Lab was developed by BioRad. Classroom kits can be ordered from www.biorad.com.
257
For more information about genetic transformation in the pGLO Lab, please visit
the BioRad website and download the Biotechnology Explorer™: pGLO Bacterial
Transformation Kit manual. To access the manual, click on “Life Science Education”
under “online catalog.” Then, click on “pGLO Bacterial Transformation Kit,”
“Literature,” and “pGLO Bacterial Transformation Kit, Biotechnology Explorer,
Instruction Manual, Revision E.”
258
Materials
An asterisk indicates that ordering information is available below.
Genscope
• access to Apple computers, one per group of 2 students or one computer with a
projection device
DNA Lego
• 1 DNA Teacher Pack*
• 6 DNA Student Sets*
Transformation and Genetic Engineering
• 1 DNA Teacher Pack*
• 6 DNA Student Sets*
RNA Bingo
• “RNA Bingo” and “Genetic Code” handouts
• index cards
• a bag or hat
Video Viewing
• “Exploring Our Molecular Selves” video
pGLO Lab
• pGLO Bacterial Transformation Kit
*Ordering Information
Item
Supplier and Contact Info
Genscope
DNA Teacher Pack
DNA Student Set
pGLO Bacterial
Transformation Kit
UV lamp
“Exploring Our
Molecular Selves”
video
genscope.concord.org
Notes
Will work only on
Apple computers!
LEGO
Includes activity
www.legoeducation.com/store directions,
overheads, and 1 set
of LEGO.
LEGO
Order 1 set per four
www.legoeducation.com/store students.
BioRad
Order 1 set for 32
students.
BioRad
Order 3 per class.
Download the
National Human Genome
Multimedia
Research Institute
Educational Kit.
www.genome.gov/Pages/
(Online video is
EducationKit/index.html
included.)
259
Price per
Item
Free
download
$89.00
$59.00
$75
$30
Free
download
Preparation for Unit
Several weeks before starting your genetics unit, order the LEGO kits, pGLO kit, and the
video. About a week before the pGLO lab, prepare nutrient agar plates as suggested on
page 7 of the pGLO kit manual. A day before the lab, prepare the starter plates.
Procedure
Days One and Two: Genscope
Genscope is a genetics computer simulation program designed to model basic
principles of genetics. Have students use the software to generate a population of dragons
and observe the dragons’ traits. Discuss with your class the traits observed in the dragons,
the frequency of these traits, and the patterns apparent in the traits expressed. Dragon
traits include wings, horns, number of legs, color, ability to breathe fire, and scales.
On the second day of the activity, have students use Genscope to determine the
frequency of gene expression in a population of dragons and in the class. Students should
do this by creating a large population of dragons. Frequencies for pairs of students should
be calculated first, and then class data should be compiled.
Finally, introduce the idea of human traits. Ask students what traits they believe
humans have. Determine how often a specific trait, such as tongue rolling, or a widow’s
peak, occurs in the class.
Days Three through Five: DNA Lego
DNA Structure
On the third day of this unit, divide the class into groups of four. Have each group
discuss what they already know about DNA. Ask them to record their comments and
share them with the class. Ask students what, if any, connection might exist between the
work they did with the dragon traits and DNA.
Give each group a DNA Lego kit. Have students sketch one of each type of piece
in the set. Show students the overhead from the DNA Lego Teacher’s Guide that shows
the different pieces in the set and have them label their sketches. Then ask them to build a
DNA model.
Ask students what they noticed about DNA as they were building their model. For
example they may notice that sugar connects to a phosphate and only C’s, G’s, A’s, and
T’s stick to each other. Talk about the difference between the Lego model and an actual
260
DNA model. (Talk about things like size, bonding, and actual structure. Refer to the
background section or a biology textbook for more information.)
Talk about how DNA, genes, and chromosomes are related. Explain to students
about complementary base pairs and write a list of the pairs on the board. Ask students to
record this list in their notes.
DNA Replication
On the fourth day talk about how DNA is replicated. Review the parts of the cell
and where DNA is found in the cell. Have students use the DNA Legos to model the
untwisting, unzipping, matching up, zipping, and twisting of DNA replication. Ask
students why DNA needs to replicate and what may happen if DNA is not replicated
correctly.
Translation and Protein Synthesis
On the fifth day have students use the DNA Legos to model translation. Large
Styrofoam balls can be used to represent amino acids. These balls can be attached to
RNA codons. Each ball is a different color and is attached to only one set of three RNA
nucleotides.
Talk to students about the importance of proteins in bodily function. Use
examples such as insulin to illustrate the role of proteins and the consequences of having
limited production of proteins.
Use chalk to draw a large nucleus on each group’s table. Label one student from
each group “ribosome” and have students model translation by untwisting and unzipping
the DNA. Then have them match up the RNA nucleotides. Review the rules for matching
base pairs for DNA and discuss the rules for RNA. Have students build RNA molecules,
rezip and twist the DNA molecule, and move away from the nucleus to pick up codons
with amino acids attached. The “ribosome” should finish the process by connecting the
amino acids to make a protein.
Day Six: Transformation and Genetic Engineering
Assemble a large DNA molecule using multiple sets of the Lego. Insert a new
gene and show how a new protein is built. This sets the stage for the pGLO
transformation lab. Discuss the process for producing proteins and the engineering design
process and how they work together in bioengineering.
Day Seven: RNA Bingo
Lead a game of RNA Bingo to help students become familiar with the genetic
code. Hand out copies of the “RNA Bingo” and “Genetic Code” worksheets, one to each
student. Note that there are four different “RNA Bingo” sheets, so a quarter of the class
will win at once. (Many free Bingo Card generators are available online if you choose to
make a class set.)
261
Place index cards marked “A,” “U,” “G,” or “C” in a bag. Pull out one letter.
Write the letter on the board. Return the letter to the bag. Pull out a second letter and
record it on the board. Return that letter to the bag. Pull out a third letter and write it on
the board. Call out the three letters and have students use their copy of the genetic code to
determine the amino acid that those three bases code for. Students should mark that
amino acid on their bingo card using a penny or other suitable marker.
Day Eight: Video Viewing
There are a variety of resources available online as part of a multimedia
educational kit from the National Human Genome Institute and National Institutes of
Health. You can download the short video “Exploring Our Molecular Selves” from the
following website: www.genome.gov/Pages/EducationKit/index.html.
After viewing the video, discuss with students how useful or limited the LEGO
model is at representing the structure and function of DNA.
Days
Days Nine through Eleven: pGLO Lab
Overview
On the first day of the pGLO lab, review the background material covered in the
Biotechnology Explorer: pGLO Bacterial Transformation Kit literature. Discuss with
your students the process of genetic transformation and how they will know if their
bacteria have been transformed. Give students an overview of the lab procedure. You
may want to pass out the “Transformation Kit—Quick Guide” (page 14 of the pGLO kit
manual) or make your own abbreviated set of directions and share it with students.
Lab
On the second and third day, conduct the pGLO lab as described in the manual. It
is important to have many volunteers on hand during the lab to answer questions about
the procedure. Ideally, you should have one volunteer per two groups of students.
Analysis
On the fourth day have students look at their plates with the UV lights.
Wrap-Up
Review the engineering design process. Discuss how it applies to the pGLO lab
and to genetic engineering in general.
262
STUDENT WORKSHEET
RNA Bingo (1)
phenylalanine
valine
histidine
lysine
leucine
serine
alanine
proline
isoleucine
asparagine
tyrosine
threonine
methionine
aspartic acid
glutamine
glutamic acid
263
STUDENT WORKSHEET
RNA Bingo (2)
cysteine
glycine
methionine
glutamine
tryptophan
phenylalanine
valine
proline
arginine
aspartic acid
histidine
glutamic acid
serine
asparagine
tyrosine
isoleucine
264
STUDENT WORKSHEET
RNA Bingo (3)
threonine
isoleucine
tryptophan
tyrosine
cysteine
valine
methionine
glutamine
aspartic acid
proline
asparagine
aspartic acid
phenylalanine
glycine
serine
lysine
265
STUDENT WORKSHEET
RNA Bingo (4)
alanine
serine
asparagine
tyrosine
lysine
tryptophan
methionine
threonine
aspartic acid
phenylalanine
valine
histidine
cysteine
isoleucine
proline
glycine
266
STUDENT WORKSHEET
The Genetic Code
Second Base
U
C
A
G
UUU PhenylUUC alanine
UCU Serine
UCC
UCA
UCG
UAU Tyrosine
UAC
UGU Cysteine
UGC
UAA Stop codon
UAG Stop codon
UGA Stop codon
UGG Tryptophan
CGU Arginine
CGC
CGA
CGG
First Base
UUA Leucine
UUG
C
A
G
CUU Leucine
CUC
CUA
CUG
CCU Proline
CCC
CCA
CCG
CAU Histidine
CAC
AUU Isoleucine
AUC
AUA
ACU Threonine
ACC
ACA
ACG
AAU Asparagine
AAC
AGU Serine
AGC
AAA Lysine
AAG
AGA Arginine
AGG
GCU Alanine
GCC
GCA
GCG
GAU Aspartic
GAC acid
GGU Glycine
GGC
GGA
GGG
AUG Methionine
start codon
GUU Valine
GUC
GUA
GUG
CAA Glutamine
CAG
GAA Glutamic
GAG acid
U
C
A
G
U
C
A
G
U
C
A
G
U
C
A
G
Table from Freeman, Scott, Biological Science, Upper Saddle River, New Jersey: Prentice Hall, 2002.
267
Third Base
U
Conclusions
By the end of this unit, students should:
1. be familiar with the structure and function of DNA;
2. understand how DNA replicates;
3. be able to explain how genetic transformation can be used to transfer
genes from one living thing to another; and
4. understand how genes, proteins, and traits are related.
Vocabulary
amino acid: a compound containing an amine group (NH2), a carboxylic acid group
(COOH), and side groups; the building blocks of proteins
anticodon: a sequence of three nucleotides in transfer RNA that bind to a messenger
RNA with a complementary sequence
bacterial plasmid: a circular strand of DNA
chromosome: a single long, coiled strand of DNA; located in the nucleus
codon: a sequence of three nucleotides of DNA or RNA; codes for one amino acid
DNA: a nucleic acid that carries genetic information
evolution: the theory that all organisms on earth have changed over time due to natural
section
gene: a sequence of DNA that codes for a specific trait
genetic engineering: inserting genes into DNA, removing genes, or changing part of a
gene
Human Genome Project: a federally-funded research project to identify all 20,000 –
25,000 genes in human DNA
mRNA: a type of RNA that carries the instructions for protein synthesis
mutation: a change in the genetic material of an organism
nucleotide: a monomer that can be polymerized to form DNA or RNA; made of a fivecarbon sugar, a phosphate group, and a nitrogen base
268
replication: a process in which a strand of DNA is reproduced
protein: a chain of amino acids
recombinant DNA: new DNA made from two or more types of DNA
tRNA: a form of RNA molecule used for matching amino acids to messenger RNA
codons; delivers amino acids to messenger RNA at the ribosomes
trait: an inherited characteristic
transcription: the process of copying DNA code onto an RNA molecule
translation: the process by which proteins are synthesized from messenger RNA
molecules
269
References
DNA Workshop
www.pbs.org/wgbh/aso/tryit/dna/#
Evolution Web Site
Genomics and Its Impact on Science and Society: The Human Genome Project and
Beyond
www.ornl.gov/sci/techresources/Human_Genome/publicat/primer2001/index.shtml
Journey into DNA
www.pbs.org/wgbh/nova/genome/dna.html#
Extensions
Mystery of the Crooked Cell
www.bumc.bu.edu/Dept/Content.aspx?DepartmentID=285&PageID=7356
270
Chapter Six: Suggested Resources for
Further Information
Websites
www.nsf.gov
www.stemteams.org
www.wepan.org
www.wieo.org
www.engineeringgk12.org/students/so_you_want_to_be _an_engineer/the_engineering_alphabet.htm
Appendices
Appendix A: 4 Schools for WIE Partnership
Agreements
1. Industry Representative Partnership Agreement
2. Middle School Partnership Agreement
3. Engineering Student Partnership Agreement
Appendix B: Initial Training Worksheets
1. Relating Classroom Activities to Engineering
Frameworks
2. Engineering Design Process
3. Solar Design Project
4. Challenge Project
5. Group Challenge Project Brainstorm
6. Lego Balance (Parts 1 and 2)
7. From “Equity, Excellence, and ‘Just Plain Good
Teaching’”
8. Gender-Equitable Practices
9. Qualities of Authentic Assessment
10. Linking Standards to Assessment
11. Creating a Standards-Based Project
Appendix C: Evaluation Tools
1. Student Attitudes Survey
2. Administration of Survey
3. Qualitative Surveys for STEM Team Members
Appendix D: STEM Team Contract
Appendix E: Sample Manual Format
271
References
1 Suzanne Brainard, “Globally Diversifying the Workforce in Science and Engineering,” WEPAN (2004), http://www.wepan.org/
intlsession.html.
2 Catherine Freeman, “Trends in Educational Equity of Girls & Women,” National Center for Education Statistics (2004),
http://nces.ed.gov/pubs2005/equity/.
3 American Association of Engineering Societies, “Engineering and Technology Degrees,” Engineering Workforce Commission
(2002), http://ewc-online.org/publications/degrees.asp.
4 Commission on the Advancement of Women and Minorities in Science, Engineering, and Technology Development, “Land of
Plenty: Diversity as America's Competitive Edge in Science, Engineering, and Technology,” National Institute for Community
Innovations (2000).
5 L. Brush, “Cognitive and Affective Determinants of Course Preferences and Plans,” Women and Mathematics, ed. S. F. Chipman,
L.R. Brush, and D. M. Wilson, (Hillsdale, NJ: Laurence Erlbaum Associates, 1985), 123-150.
6 Josh Douglas, Eric Iverson, and Chitra Kalyandurg, “Engineering in the K-12 Classroom: An Analysis of Current Practices and
Guidelines for the Future,” (Washington, D.C.: The American Society for Engineering Education, 2004),
http://www.engineeringk12.org.
7 D. Baker and R. Leary, “Letting Girls Speak Out about Science,”
Journal of Research in Science Teaching, 32 (1995): 3-27.
8 L. J. Sax, “Retaining Tomorrow's Scientists: Exploring the Factors that Keep Male and Female College Students Interested in
Science Careers.” Journal of Women and Minorities in Science and Engineering, 1 (1994): 45-61.
9 D. Bennet, “Voices of Young Women in Engineering,” Center for
Children and Technology (Educational Development Center, May 1996): 1-13, http://www2.edc.org/CCT/publications_report_
summary.asp?numPubId=89.
10 S. V. Rosser, “Female-Friendly Science: Applying Women's Studies Methods and Theories to Attract Students,” (Elmsford, NY:
Pergamon Press, 1990).
11 Clifford Adelman, “Women and Men of the Engineering Path,” A Model for Analyses of Undergraduate Careers,” The U. S.
Department of Education and The National Institute for Science Education, (1998): 39, 58.
12 Cinda-Sue Davis, et al. The Equity Equation: Fostering the Advancement of Women in the Sciences, Mathematics, and Engineering
(Hoboken, NJ: Wiley, 1996).
13 Brush, 123-150.
14 J. S. Eccles, A. Wigfield, R. D. Harold, and P. Blumenfeld, “Age and Gender Differences in Children's Self- and Task-Perceptions
during Elementary School,” Child Development, 64 (1993): 830-847.
15 F. M. Haemmerlie and R. L. Montgomery, “Goldberg Revisited: Profemale Evaluation Bias and Changed Attitudes towards
Women by
Engineering Students,” Journal of Social Behavior and Personality, 6, 2. (1991): 179-194.
16 B. Clewell, P. B. Campbell, “Taking Stock: Where We've Been, Where We Are, Where We're Going,” Journal of Women and
Minorities in Science and Engineering, 8 (2002): 255-284.
17 Eccles, 830-847.
18 Mary Thom, “Balancing the Equation: Where are the Women and Girls in Science, Engineering, and Technology?” (National
Council for Research on Women: New York, New York): 174.
19 B. Clewell, K. Darke, and R. Sevo, “Meeting the Challenge: The
Impact of the National Science Foundation's Program for Women and
Girls,” Journal of Women and Minorities in Science and Engineering, 8 (2002): 285-303.
20 Haemmerlie and Montgomery, 179-194.
21 M. Knight and C. Cunningham, “Draw an Engineer Test (DAET): Development of a Tool to Investigate Students' Ideas about
Engineers and Engineering, in American Society of Engineering Education,” Proceedings of the 2004 American Society for
Engineering Education Annual Conference and Exposition, Salt Lake City, Utah, 2004.
22 Bennet, 1-13.
23 S. Osipow and W. B. Walsh, “Career Counseling for Women,” (Hillsdale, NJ: Lawrence Erlbaum Associates, 1994): 17, 249.
24 Irene Goodman, et al., “Final Report of the Women's Experiences in College Engineering (WECE) Project,” Goodman Research
Group, (2002): 45.
25 H. S. Astin and L. J. Sax, “Developing Scientific Talent in Undergraduate Women,” The Equity Equation: Fostering the
Advancement of Women in the Sciences, Mathematics, and Engineering, C.-S. Davis, et al., Editors. 1996, Jossey-Bass Publishers:
San Francisco. p. 96-121.
26 Osipow and Walsh, 239.
27 Thom, 174.
28 Bennet, 1-13.
29 J. S. McIlwee and J.G. Robinson, “Women in Engineering: Gender, Power, and Workplace Culture,” (Albany, NY: State
University of New York Press, 1992).
30 Wellesley College Center for Research on Women, “How Schools Shortchange Girls: A Study of Major Findings on Girls and
Education,” Washington, D.C.: American Association of University Women Educational Foundation, 1992.
31 Wellesley College Center for Research on Women.
32 Clewell and Campbell, 255-284.
33 The New England Consortium for Undergraduate Science Education. “Achieving Gender Equity in Science Classrooms: A Guide
for Faculty,” (1996), http://www.brown.edu/Administration/
Dean_of_the_College/homepginfo/equity/Equity_handbook.html.
34 Thom, 174.
35 Bennet, 1-13.
36 National Research Council, “National Science Education Standards,” (1996), http://www.nap.edu/readingroom/
books/nses/notice.html.
272
37 David Driscoll, “Commissioner’s Update,” Massachusetts Department of Education; (January 21, 2003).
38 Greg Pearson and A. Thomas Young, eds., Technically Speaking: Why All Americans Need to Know More about Technology,
(Washington, D.C.: National Academy Press, 2002).
39 Pearson and Young.
40 A. L. Gardner, C. L Mason, and M. L. Matyas, “Equity, Excellence, 'Just Plain Good Teaching,'” American Biology Teacher
(February 1989): 72-77.
273
Appendix A1: Industry Representative
Partnership Agreement
Industry Representative Partnership Agreement
(Name of industry partner) has agreed to contribute to the STEM Team project at (name of
institution) in the following manner:
•
Recruiting a primary female engineer to serve as industry representative. Recruiting an
alternate female engineer if the primary engineer is unable to participate in the program.
The industry representative will be an active participant on the STEM (Science,
Technology, Engineering, and Mathematics) teams.
•
The industry representative will attend team meetings and team training sessions.
•
The industry representative will conduct in-class work with the STEM team at the
participating middle schools for up to eight hours per month.
In return for participating in the program, the industry representative and her company
will receive the following benefits:
•
An opportunity to work with and exchange ideas with other professionals in the area.
•
An opportunity to reach out to female middle school students and encourage them to
consider an engineering education.
•
An opportunity to work with female college engineering students who may be interested
in career opportunities at the company.
•
Public relations recognition in press releases distributed by the university and industry
partners.
Thank you very much for your participation.
_________________________________
Individual Industry Representative
______________________________
Corporate Liaison or Supervisor
274
Appendix A2: Middle School
Middle School Partnership Agreement
The insert your school partner Middle School has agreed to contribute to the STEM Teams
project at your institution in the following manner:
•
•
•
•
•
•
Selecting science or technology teachers from the middle school that we feel will benefit the
most from working with this program;
Providing 40 hours of release time per year through substitutes for each teacher participating
so that they can attend the associated professional development sessions (STEM Team
training sessions and meetings);
Allowing participating teachers to use the gender-neutral applications in their classrooms;
Sharing the standardized test scores from the participating classes for evaluation purposes;
Assisting in distributing and gathering required permission forms for additional assessment
of the project; and
Allowing the female engineering students and professionals to participate on a regular basis
in the selected classrooms.
Teachers will be active participants on the STEM (Science, Technology, Engineering, and
Mathematics) teams:
•
•
Teachers will attend team meetings and team training sessions.
Teachers will help to develop curriculum and implement it in their classrooms.
In return for participating in the program, the teachers and the school will receive the
following:
•
•
•
•
•
Valuable training in incorporating engineering applications into existing science curriculum.
The opportunity to work with and exchange ideas with other professionals in several school
districts.
The opportunity to work with female college engineering students and professionals while
introducing gender-neutral, engineering-based applications in the classroom.
$____ in classroom materials per school
A stipend of $____ paid to individual teachers.
______________________________
Middle School Principal
_____________________________
Middle School Teacher
275
Appendix A3: Engineering Student
Partnership Agreement with Engineering Students
Students will be active participants on the STEM (Science, Technology, Engineering, and
Mathematics) teams.
•
Students will attend team meetings and team training sessions as required.
•
Students will conduct in-class activities with the STEM team at the participating middle
schools as required.
•
Total student time commitment is approximately 30 hours per semester.
In return for participating in the program, students will receive the following:
•
The opportunity to work with and exchange ideas with professionals and students at area
universities;
•
The opportunity to work with middle school students and potentially interest them in an
engineering education;
•
The opportunity to enhance their resumes with teaching experience and participation in
an NSF grant outreach program; and
•
A stipend in the amount of $___/hr.
_______________________________
Engineering Student
276
Appendix B1: Relating Classroom Activities
to Engineering Frameworks
Note: As one part of the training workshop, we looked at teachers’ current curriculum and identified which areas of the
technology and engineering standards were already being covered. Below is an example of the table we created:
Relating Classroom Activities to the Engineering Frameworks
Appendix B2: Engineering Design
Design Process
The Engineering Design Process
Steps of the design process:
1. Identify the need or problem
2. Research the need or problem
o Examine current state of the issue and current solutions
o Explore other options via the Internet, library, or interviews
3. Develop possible solution(s)
o Brainstorm possible solutions
o Draw on mathematics and science
o Articulate possible solutions in two and three dimensions
o Refine possible solutions
4. Select the best possible solution(s)
o Determine which solution(s) best meet(s) the original
requirements
5. Construct a prototype
o Model the selected solution(s) in two and three dimensions
6. Test and evaluate the solution(s)
o Does it work?
o Does it meet the original design constraints?
7. Communicate the solution(s)
o Make an engineering presentation that includes a discussion of how the
solution(s) best meet(s) the needs of the initial problem, opportunity, or need
8. Redesign
o Overhaul the solution(s) based on information gathered during the tests and
presentation
Massachusetts Science and Technology/Engineering Curriculum Framework
May 2001
278
Appendix B3: Solar Design Project
Solar Room Design Project
(90 Minutes)
Materials:
•
•
•
Masking tape
Lightweight plastic sheets (one per team)
Paper
Challenge:
Design a solar room to be added onto the back of an existing house, which will offer the most
light and energy efficiency for the homeowner.
Use the engineering design process to brainstorm a design considering all design variables. As
a team, select your best solution and use the materials supplied to create your prototype room.
Report to the group why you choose your solution and how you would test and evaluate the
solution.
279
Appendix B4: Challenge Project
Challenge Project Worksheet
STEM Team Workshop
The Challenge Project is a joint effort among all members of the STEM Team and should be a
foundation that will help each STEM Team incorporate engineering into the classroom in a
gender-inclusive manner.
Project Types: The Challenge Project can be a building project (example: building an
“Earthquake Table” to be used in the classroom), a manipulative project (example: putting
together a presentation board on the differences between science and engineering), or an activity
plan (a lesson that would incorporate the expertise of the STEM Team members). All projects
must be reviewed by workshop leaders.
Time for Project: We will set aside time during the workshops to work on the project as a
group. We expect that each team will work on the project both during and outside the workshop.
Session 1
1 hr
Session 2
2 hrs
Session 3
Session 4
Session 5
1 hr
2 hrs
15 min.
Discussing ideas for project.
Plan project.
Gather materials. Meet with
STEM Team.
Continue work on project.
Finish work on project.
Present project to STEM Team.
During workshop
Outside workshop
During workshop
During workshop
During workshop
Project Presentations: Each STEM team will do a presentation of its project on the final day of
the workshop. During the presentation, the following questions should be addressed:
1. Why was this project chosen?
2. How will each STEM Team member contribute to the project?
3. What does this project communicate about engineering to the students?
4. How are gender-equitable strategies used in the project?
280
Appendix B5: Group Challenge Project
Brainstorm
Group Challenge Project Brainstorm
STEM Team Workshop
Please use these questions to help brainstorm ideas for the challenge project.
STEM Team Resources
1. What ideas for activities or presentations do you currently have for this project?
2. What resources do you bring to the STEM Team? (interests, hobbies, talents, areas of
expertise)
Local Resources
3. Briefly describe the neighborhood around the school. (urban, suburban, rural)
4. List at least three “unique features” about your geographic area. (historic sites, points of
interest, public works facilities)
5. What local resources are available to you? (libraries, museums, research labs, universities,
businesses)
Notes:
281
Appendix B6: Lego Balance
(Parts
(Parts 1 and 2)
Lego Balance Part 1
Build your own pan balance out of LEGO, string, and a set of standard metric weights.
Here are your design specifications:
•Your balance must be able to weigh objects between 0 and 50 grams.
•Your balance must be able to measure to within 0.5 grams of the actual mass of the
object. (You’re welcome to make it more precise, of course.)
Other than these two constraints, your design is up to you. Each group will get a set of metric
weights. You may use these for testing or incorporate them into your balance.
282
Lego Balance Part 2
Once you have built your balance, you may test it (and improve it) as many times as you wish.
A regular balance is available so that you can compare the results from it with those from your
LEGO balance.
When you are confident that your balance can measure to within 0.5 grams of the actual mass,
you are ready for the official test. You will be given a basket containing four objects labeled 1,
2, 3, and 4. Mass each object and write down the answer below.
Object Number
Mass in Grams
1
2
3
4
283
Appendix B7: From “Equity, Excellence and
‘Just Plain Good Teaching’”
Teaching’”
From “Equity, Excellence, ‘Just Plain Good Teaching’”
By April L. Gardener, Cheryl L. Mason, and Marsha Lakes Matyas
Source: www.enc.org/topics/equity/articles/document.shtm?input=ACQ-111551-1551
Table 1. Criteria for Equitable Science Activities
∗ Teacher is enthusiastic and has equal expectations for all students
∗ Written materials and verbal instructions use gender-free language
∗ Relevance of activity to students’ lives is stressed
∗ “Hands-on” experience is required for all students.
∗ Small group work is used.
∗ Activity develops science process skills.
∗ Exercise does not demand one “right” answer.
∗ Activities do not use materials or resources exclusively familiar to white, male students.
∗ Career information relevant to the activity is presented.
∗ Examples of female and minority role models are included in the follow-up.
Table 2. Our Table of Criteria for Gender-Equitable Engineering Activities
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
284
Appendix B8: GenderGender-Equitable Practices
GENDER-EQUITABLE PRACTICES
1
You can complete this form as a self-assessment. Look over the list of gender-equitable practices below. Check
the ones you feel you implement in your interactions with students and also those you feel you may need to
improve. No one else will see this list; it can help you only if you are honest in your responses.
You can use this form to initiate small group discussions. After you have finished completing the form, discuss
with a small group how to best address gender-equity in your classroom. Please take about 15 minutes for your
group work. Ask one member of the group to report your “best practices” back to the larger group.
I Could Use
Help with This
Not Applicable
________
________
When girls and boys are working together in groups, I intervene
if girls are consistently being ignored or relegated to
________
stereotypical roles such as “secretary.”
________
________
I recognize that girls are not a monolithic group, nor are boys.
I avoid sweeping generalizations that perpetuate stereotypes ________
such as “Boys are....” or “Girls are….”
________
________
When young people give each other unwanted or harassing sexual
attention, whether or not the target appears embarrassed, upset,________
scared or isolated, I intervene to stop the behavior.
________
_______
I deliberately make an effort to reverse gender stereotypes
(e.g., I ask girls to demonstrate how to use a new science
apparatus, use computer software or move a heavy object
and boys to demonstrate how to clean test
tubes, take notes, or organize materials).
________
________
________
I encourage girls to take initiative and leadership in the lab
such as by organizing a lab team, delivering a team report,
or chairing a committee.
________
________
________
I Do This
1. Promoting Nonbiased/Nonstereotyped Behavior
I encourage girls to develop public speaking skills and to act
as leaders (e.g., group leader, class president, peer mentor). ________
1
This list has been adapted by Fern Marx, Sumru Erkut, and Jacqueline P. Fields for the Raising Confident and
Competent Girls Project from “Self-Assessment on Gender Equity Issues” in Kathryn A. Wheeler, How schools
can stop shortchanging girls (and boys): Gender-equity strategies. Center for Research on Women Working paper
no. 6. Wellesley, MA: Wellesley College, 1993.
285
I Do This
I Could Use Not Applicable
Help with This
2. Attitudes and Expectations
I respect and support students whose cultures do not
foster individual exhibition of competence.
________
________
________
I do not assume that all teenagers are heterosexual.
________
________
________
I keep up with the literature on gender and cultural bias
in standardized testing.
________
________
________
I actively encourage all students, including
low-achieving students, to remain in school.
________
________
________
________
________
________
I am open to constructive criticism from others about my
attitudes and actions with regard to gender bias.
________
________
________
I seek out staff development workshops that include a focus
on issues of gender bias and diversity.
________
________
________
________
________
Regardless of race or ethnicity, class or gender, I encourage
all students to consider continuing their education beyond
high school.
3. Raising Awareness about Gender Bias
I involve students in informal research studies to raise
awareness of how gender bias occurs (e.g., tally the number of ________
times boys vs. girls ask questions; discuss how gender
bias impacts their experiences at school).
A colleague and I observe each other’s teaching to point
out gender-biased practices.
________
________
________
When I hear students making sexist, homophobic, or racist
jokes, I intervene and explain why these are inappropriate.
________
________
________
I point out to colleagues when their behavior is gender-biased,
because I don’t believe that it will stop on its own.
________
________
________
286
I Do This
I Could Use
Help with This
Not Applicable
________
________
________
I never make racist, sexist, classist, or homophobic comments,
even as a “joke.”
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
________
My curriculum includes the perspectives and experiences
of women and girls as well as men and boys.
________
________
________
I pay attention to the implicit as well as explicit gender,
race, and class messages in my curriculum.
________
________
________
________
________
4. Role Models
I try to model nonbiased behavior.
The decorations in my classroom reflect the multi-cultural
nature of our society and show men and women of diverse
ethnic groups in various roles, especially women of color
in science and technical jobs.
When planning guest speakers, I invite men and women,
some of whom are engaged in nontraditional roles.
My classroom decor (pictures, bulletin boards, books, etc.)
reflects the fact that women constitute half of the world’s
population.
5. Teaching Techniques
I often ask students to do cooperative projects as well
as individual work, particularly for computer, math, and
science projects.
I try to use real-life examples that both female and male
adolescents can relate to (e.g., when teaching how to calculate ________
averages, I illustrate with several types of examples from
everyday life, not just batting averages).
I discourage competition between boys and girls as groups.
________
Whenever possible, when evaluating students’ understanding
of subject matter, I use several forms of assessment, such as ________
essays, multiple-choice tests, journals, photographs, and
performance tests.
I create opportunities for both girls and boys to have
leadership positions.
6. Curriculum
I often make a conscious effort to choose curricular
materials that challenge gender stereotypes and show diversity. ________
287
I Do This
I Could Use
Help with This
Not Applicable
________
________
________
________
After asking a question, I make an effort to wait a few seconds
before calling on anyone so students can have “think time”
________
if they need it.
________
________
I recognize that among both boys and girls, differences in
cognitive, physical, and emotional development can
influence classroom behavior and learning.
________
________
________
________________________________________________
________
________
________
_______________________________________________
________
________
________
_______________________________________________
________
________
________
_______________________________________________
________
________
________
7. Fostering Student Participation in Class
I make a conscious effort to ensure that I give ethnic, linguistic,
and racial minority teens as much attention as majority
________
youth. I am aware that minority girls tend to get
especially shortchanged.
I don’t rely solely on students who volunteer to ask and answer
questions.
________
Other Gender-Equitable Practices
288
Appendix B9: Qualities of Authentic
Assessment
Qualities of Authentic Assessment
Authentic assessment...
•
Is reached by providing experiences that are congruent with real-life situations;
•
Is not based on recall and there is usually not one right answer;
•
Requires the student to use and practice skills and knowledge learned in the course;
•
Is able to measure different skills;
•
Assumes that the students have basic skills;
•
Requires higher level thinking; and
•
Is tied to the course standards.
289
Appendix B10: Linking Standards to
Assessment
Linking Standards to Assessment
1. Identify the standard(s) that you need to assess.
2. Choose a project that will be an effective tool for students to communicate how well
they know the content, concepts, and processes required by the standard(s).
3. Develop assessment criteria that correlate to the standards.
4. Write a scoring rubric using the assessment criteria.
290
Appendix B11: Creating a
StandardsStandards-Based Project
Creating a Standards-Based Project
1. List the standards (science, engineering, and others) that can be applied to the project as
it is written.
2. Revise the existing assessment criteria to reflect the chosen standards.
OR
1. Think of ways in which you might be able to revise the project to meet engineering and
science standards.
2. Make a list of standards (science, engineering, and others) that you want to assess.
3. Determine the tasks that students will be required to complete in the revised project.
4. Write assessment criteria that will support your standards.
291
Appendix C1: Student
Student Attitudes Survey
Pre-Intervention Survey
STUDENT ASSENT FOR PARTICIPATION
Today I would like to ask you to complete a short survey on attitudes toward
mathematics, science, and engineering and careers in these fields. Your
participation is voluntary. If you decide you don’t want to complete the
survey or you wish to stop at any time or to skip questions, you are free to do
so.
If you would like to complete this survey, please check “Yes”
_____ Yes _____ No
Your Name: _____________________________________________
Your School’s Name:______________________________________
Your Teacher’s Name: _____________________________________
Today’s Date: ____________________________________________
292
The following questions are about engineering. Please read
this paragraph before you answer the questions.
Engineering is a career that uses math and science to invent new products and solve
problems that improve everyone’s life. There are many different types of engineering,
such as chemical, electrical, computer, mechanical, civil, environmental, biomedical, and
design. The word engineer comes from the Greek word for imagine. Engineers or
“imagineers” not only build bridges and cars but also invent new fabrics, foods, and even
virtual reality amusement parks. In fact, engineers work with almost everything we eat,
drink, wear, touch, see, smell, and hear in our daily lives.
On the following pages is a series of sentences. Please mark your answer sheets by
indicating how you feel about them. Suppose a statement says:
Example 1:
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
I like engineering.
As you read the sentence, you will know whether you agree or disagree. If you
strongly agree, check the box under Number 5. If you agree, but not so strongly,
or you only "sort of" agree, check the box under 4. If you disagree with the
sentence very much, check the box under 1 for strongly disagree. If you disagree,
but not so strongly, check the box under 2. If you are not sure about a question or
you can't answer it, check the box under 3.
Even though some statements are very similar, please answer each statement.
This is not timed; work fast, but carefully.
There are no right or wrong answers. The only correct responses are those that are
true for you. Whenever possible, let the things that have happened to you help you
make a choice.
PLEASE FILL IN ONLY ONE ANSWER PER QUESTION.
293
1. ATTITUDES TOWARD ENGINEERING
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
1. A degree in engineering will allow
me to obtain a well-paid job.
2. I am not interested in any career
that uses math and science.
3. I like fixing broken appliances.
4. At the science museum, I like the
exhibits on robotics.
5. A degree in engineering will allow
me to obtain a job I like.
6. I have no interest in helping
design the space station.
7. Engineering skills will allow me to
better society.
8. A degree in engineering will give
me the kind of lifestyle I want.
9. I am interested in designing better
artificial limbs.
10. I would like to learn how to make
safer cosmetics.
11. Engineering interests me because
I like to think about solving
technical problems.
12. I am not interested in what makes
machines work.
294
2. ATTITUDES TOWARD MATH
Please use the same instructions you used for completing the Attitudes toward
Engineering.
1. Math is a worthwhile, necessary
subject.
2. Math is not important for my life.
3. Math has been my worst subject.
4. I see math as something I won’t use
very often when I get out of high
school.
5. I would consider choosing a career
that uses math.
6. I study math because I know how
useful it is.
7. Math is hard for me.
8. I’ll need a good understanding of
science for my future work.
9. I’m not the type to do well in math.
10. Most subjects I can handle OK, but I
just can’t do a good job in math.
11. I am sure I could do advanced work
in math.
12. I can get good grades in math.
13. I’m no good in math.
295
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
3. ATTITUDES TOWARD SCIENCE
Math.
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
1. I am sure of myself when I do
science.
2. I would consider a career in
science.
3. I don’t expect to use much
science when I get out of school.
4. Knowing science will help me
earn a living.
5. I’ll need science for my future
work.
6. I know I can do well in science.
7. Science will not be important to
me in my life’s work.
8. Science is a worthwhile,
necessary subject.
9. Most subjects I can handle OK,
but I just can’t do a good job in
science.
10. I am sure I could do advanced
work in science.
296
4. YOUR FUTURE
Here is list of jobs that use knowledge of math, science, and engineering. How
interested are you in these kinds of jobs? If you are Very Interested, check the box
under Number 4. If you are Somewhat Interested, check the box under 3. If you are
Not So Interested, check the box under 2. If you Not At All Interested, check the box
under 1.
true for you.
Not At All
Interested
1
Not So
Interested
2
1. Physicist
2. Nurse
3. Auto Mechanic
4. Medical Doctor
5. Electrician
6. Computer Technician
7. Welder
8. Chemist
9. Engineer
10. Accountant
11. Biologist
12. Architect
297
Somewhat
Interested
3
Very
Interested
4
5. ABOUT YOURSELF
How well do you expect to do this year in your:
Not very well
OK/Pretty well
Very well
1
2
3
English class?
Math class?
Science class?
Year of Birth: ______________
Boy
Girl
My family is: (CHECK ONE ONLY)
African American
Caucasian/ White
Asian (Please Specify): _____________________________
Hispanic (Please Specify): ___________________________
Biracial/ Multiracial (Please Specify): __________________
Other (Please Specify): _____________________________
Do you plan to go to college?
Yes
No
Not sure
Do you know any engineers?
Yes
No
Not sure
THANKS FOR YOUR HELP!
298
Post-Intervention Survey
STUDENT ASSENT FOR PARTICIPATION
Today I would like to ask you to complete a short survey on attitudes toward
mathematics, science, and engineering and careers in these fields. Your
participation is voluntary. If you decide you don’t want to complete the
survey or wish to stop at any time or to skip questions, you are free to do so.
If you would like to complete this survey, please check “Yes”
_____ Yes _____ No
Your Name: _____________________________________________
Your School’s Name:______________________________________
Your Teacher’s Name: _____________________________________
Today’s Date: ____________________________________________
299
The following questions are about engineering. Please read
this paragraph before you answer the questions.
Engineering is a career that uses math and science to invent new products and solve
problems that improve everyone’s life. There are many different types of engineering,
such as chemical, electrical, computer, mechanical, civil, environmental, biomedical, and
design. The word engineer comes from the Greek word for imagine. Engineers or
“imagineers” not only build bridges and cars but also invent new fabrics, foods, and even
virtual reality amusement parks. In fact, engineers work with almost everything we eat,
drink, wear, touch, see, smell, and hear in our daily lives.
On the following pages is a series of sentences. Please mark your answer sheets by
indicating how you feel about them. Suppose a statement says:
Example 1:
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
I like engineering.
As you read the sentence, you will know whether you agree or disagree. If you
strongly agree, check the box under Number 5. If you agree, but not so strongly,
or you only "sort of" agree, check the box under 4. If you disagree with the
sentence very much, check the box under 1 for strongly disagree. If you disagree,
but not so strongly, check the box under 2. If you are not sure about a question or
you can't answer it, check the box under 3.
Even though some statements are very similar, please answer each statement.
This is not timed; work fast, but carefully.
true for you. Whenever possible, let the things that have happened to you help you
make a choice.
PLEASE FILL IN ONLY ONE ANSWER PER QUESTION.
300
1. ATTITUDES TOWARD ENGINEERING
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
1. A degree in engineering will allow me
to obtain a well-paid job.
2. I am not interested in any career that
uses math and science.
3. I like fixing broken appliances.
4. At the science museum, I like the
exhibits on robotics.
5. A degree in engineering will allow me
to obtain a job I like.
6. I have no interest in helping design the
space station.
7. Engineering skills will allow me to
better society.
8. A degree in engineering will give me
the kind of lifestyle I want.
9. I am interested in designing better
artificial limbs.
10. I would like to learn how to make safer
cosmetics.
11. Engineering interests me because I like
to think about solving technical
problems.
12. I am not interested in what makes
machines work.
301
2. ATTITUDES TOWARD MATH
Engineering.
1. Math is a worthwhile, necessary
subject.
2. Math is not important for my life.
3. Math has been my worst subject.
4. I see math as something I won’t use
very often when I get out of high
school.
5. I would consider choosing a career
that uses math.
6. I study math because I know how
useful it is.
7. Math is hard for me.
8. I’ll need a good understanding of
math for my future work.
9. I’m not the type to do well in math.
10. Most subjects I can handle OK, but I
just can’t do a good job with math.
11. I am sure I could do advanced work
in math.
12. I can get good grades in math.
13. I’m not good at math.
302
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
3. ATTITUDES TOWARD SCIENCE
Math.
Strongly
Disagree
Somewhat
Disagree
Not
Sure
Somewhat
Agree
Strongly
Agree
1
2
3
4
5
1. I am sure of myself when I do
science.
2. I would consider a career in
science.
3. I don’t expect to use much
science when I get out of school.
4. Knowing science will help me
earn a living.
5. I’ll need science for my future
work.
6. I know I can do well in science.
7. Science will not be important to
me in my life’s work.
8. Science is a worthwhile,
necessary subject.
9. Most subjects I can handle OK,
but I just can’t do a good job
with science.
10. I am sure I could do advanced
work in science.
303
4. YOUR FUTURE
Here is a list of jobs that use knowledge about math, science, and engineering. How
interested are you in these kinds of jobs? If you are Very Interested, check the box
under Number 4. If you are Somewhat Interested, check the box under 3. If you are
Not So Interested, check the box under 2. If you Not At All Interested, check the box
under 1.
true for you.
Not At All
Interested
1
Not So
Interested
2
1. Physicist
2. Nurse
3. Auto Mechanic
4. Medical Doctor
5. Electrician
6. Computer Technician
7. Welder
8. Chemist
9. Engineer
10. Accountant
11. Biologist
12. Architect
304
Somewhat
Interested
3
Very
Interested
4
5. ABOUT YOURSELF
How well do you think you did this year in your:
Not very well
OK/Pretty well
Very well
1
2
3
English class?
Math class?
Science class?
Year of Birth: ______________
Boy
Girl
My family is: (CHECK ONE ONLY)
African American
Caucasian/ White
Asian (Please Specify): _____________________________
Hispanic (Please Specify): ___________________________
Biracial/ Multiracial (Please Specify): __________________
Other (Please Specify): _____________________________
Do you plan to go to college?
Yes
No
Not sure
Do you know any engineers?
Yes
No
Not sure
305
Please tell us how interesting you found the activities on engineering in this class:
Not at all interesting
Somewhat interesting
Please explain your answer.
THANKS FOR YOUR HELP!
306
Very interesting
Appendix
Appendix C2: Administration
Administration of PrePre- and
PostPost-Intervention Surveys
Surveys
Informed Consent
Dear Parents and Guardians:
The students at the __________ School in _________’s class will be participating in a special
project on students’ interest in mathematics and careers in math, science, engineering and
technology that use mathematics. ________________ , the principal of your child’s school, has
given permission for this project to be conducted in the class.
Permission Request for Participation:
We are asking your permission to ask your daughter or son about her/his attitudes toward
mathematics and its usefulness to different careers. The assessment will be used to evaluate how
effective the project is for increasing positive attitudes toward mathematics and careers that use
mathematics. These assessment sessions will take place at the beginning and end of the school
year and will take up to 20 minutes of classroom time. At the end of the academic year we will
receive the average MCAS scores of your son/daughter’s class. Your daughter/son’s
participation in the study is voluntary. There will be no consequences to you or your
daughter/son if she/he chooses not to participate, and your daughter/son may stop her/his
participation at any time.
Confidentiality:
The information we collect will be kept confidential and will not be shared with anyone. Only
project staff will have access to individual students' names, which will be kept in a secure file in
my office. When the information obtained in the Fall and Spring is linked, all information
identifying your daughter/son by name will be destroyed. All analyses of the information will be
carried out without identifying names and any reports coming out of this project will never
identify participants in any way.
Risks:
There are no known risks associated with the administration of the attitude measure we will use
in the study. We do not anticipate risks associated with breaking confidentiality. Neither the
students nor the schools will be identified in the published results of the evaluation.
Benefits:
The attitude statements in the survey are likely to stimulate middle school students’ thinking
about their performance in math, science, and technology. Also, they will learn about the
importance of math for a variety of careers.
If you have any questions about the project, please contact ________________, the project
evaluator, _______. You can also contact _____________, the director of the Institutional
Review Board at ______________.
Sincerely,
Project Director
307
Consent:
I understand the purpose of the project and the nature of my daughter/son’s involvement, and I
give my consent for my daughter/son’s participation in the assessment tasks.
YES___ NO___
____________________________________
Parent or Guardian's signature
________________________
Date
____________________________________
First and last name of my child
____________________________________
Name of my child's school
Please send back the signed form to your daughter/son’s teacher
Thank you
308
Administering the STEM Teams Survey
Before you begin, write the school’s name, teacher’s name, and the date on the blackboard.
Have a few extra pencils on hand.
It is very helpful to speak to the students in the first person. So for example….
“Good morning. My name is _________. I am here to ask you to complete a short survey about
attitudes towards math, science, and engineering which is part of a research study we are
doing. Your participation is completely voluntary.
Pass out the survey.
“If you would like to complete the survey, please check Yes. Please also make sure you have
written your full name, your school’s name, your teacher’s name, and today’s date on the first
sheet. Remember that if you do not wish to complete the survey stop at any time. But, of course,
we would like everyone to complete the survey. Your answers are completely confidential. Only
the researchers at insert your institution will see your answers. It is OK to fill out the survey in
pencil or pen. Does everyone have a pencil or pen?”
For those student’s who do not want to participate, you may decide to have them return the
survey to you. Ask the teacher before you get started if there is anything for non-participating
students to do while the survey is being administered.
“ Now, turn to the next page and read along with me.”
Please read page 2 in its entirety as it is written. This contains the directions for each of the
scales that follow for engineering, math, and science.
“If you have any questions about a statement or trouble understanding a word, just raise your
hand and I will be glad to answer your question.”
“Do you have any questions about the survey? Good… let’s begin. When you finish please raise
your hand and I will pick up the survey from your desk. Thank you for helping with this
important research study.”
Please check each survey as it is turned in to make sure that each student has included his or her
full name, school name, teacher’s name, and date and that the information on the last page is
complete. Allow about 20 minutes for students to complete the survey.
309
Appendix C3: Qualitative Surveys for
STEM Team Members
Project Coordinator Feedback
Name: ____________
Position:____________
STEM Team:_________
The following questions concern your experience in developing, implementing, and
coordinating the 4 Schools for WIE projects and activities during the academic year. Thanks in
advance for completing this survey. It will help all of us as we plan for next year’s activities.
.
1. Please comment on the clarity of the goals and anticipated outcomes for your teams’
project(s) for this academic year.
2. To what extent do you feel that the training provided to the teachers, industry
representatives, and students on your STEM Team adequately prepared them for
participation in classroom activities?
3. What, if any, additional training or support should be provided to your STEM
Team in the future?
4. What suggestions do you have for making the curriculum more effective for the next
implementation?
5. Thinking back over your experience this academic year in designing, implementing,
and/or supervising STEM Team activities, what stands out for you as the most
significant experience(s)?
310
6. Are the STEM Teams as presently constituted (principal investigator, project
coordinator, students, industry representatives, and teachers) the most effective structure
for implementing the STEM activities?
If not, what changes do you suggest?
7. Do you have any additional thoughts about this year’s experience that you would like to
share with us?
Thanks for your help!
311
Teacher Feedback
School: ____________
Teacher: ____________
STEM Team:_________
The following questions concern your experience in implementing the STEM Team activities in
your classrooms during the __________ academic year. Thank you in advance for completing
this survey; it will help us in planning for next year.
2. The following are the five goals and anticipated outcomes of the STEM Teams
project this year.
2. Please rate how well you think the goals were met from 1 = “did not meet this goal at
all” to 5 = “met this goal very successfully.” Circle one number in each row. If you
feel that the goal was only partially met, please explain your answer in a sentence
below the goal.
Did Not Meet
Goal at All
a. Teach concepts about the practice
and uses of engineering.
Met Goal Very
Successfully
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
Please explain:
b. Integrate engineering design
process into classroom activities.
Please explain:
c. Apply gender-inclusive approaches
in the classroom.
Please explain:
d. Communicate the connection
between classroom activities and
the state frameworks.
Please explain:
e. Capitalize on school or district
resources and local areas of interest.
Please explain:
312
1. To what extent do you feel that the training and support available to you from your
STEM Team adequately prepared you for teaching the curriculum units and
activities? Please circle one answer and explain your response below.
a. I felt the preparation from my STEM Team was:
Very Inadequate
1
Poor
2
Fair
3
Good
4
Excellent
5
Please explain:
b. I felt the support available from my STEM Team was:
Very Inadequate
1
Poor
2
Fair
3
Good
4
Excellent
5
Please explain:
3. What, if any, additional training or support would you have liked to receive from
your STEM Team?
4. How effective do you believe the curriculum and activities were in preparing
students for the engineering strand of the curriculum frameworks?
Very Inadequate
1
Poor
2
Fair
3
Good
4
Excellent
5
Please explain:
5. What suggestions do you have for making the curriculum more effective for the next
implementation?
313
6. A major part of the STEM Teams project is the idea of integrating practicing engineers
in industry and academia, as well as engineering graduate and undergraduate students, in
the classroom.
a. In your opinion, how effective was having an all-female STEM Team in providing
role models for girls in science and engineering? Please explain your answer with
specific examples, if possible.
Very Inadequate
1
Poor
2
Fair
3
Good
4
Excellent
5
Please explain:
b. How effective was an all-female STEM team for boys? Please explain your answer
with specific examples, if possible.
Very Inadequate
1
Poor
2
Fair
3
Good
4
Excellent
5
Please explain:
c. Would the same results be possible if the visitors were only from companies, or only
professors, or only engineering students? Please explain your answer.
7. Thinking back over your experience this academic year with the STEM Teams project,
what stands out for you as the most significant experience(s)?
8. How effective do you feel the curriculum was in stimulating girls’ interest in
STEM, in taking addition math/science courses and thinking about future careers related
to STEM? Please explain your answer with specific examples, if possible?
Very Inadequate
1
Poor
2
Fair
3
Please explain:
314
Good
4
Excellent
5
9. Do you feel that having an all-female STEM Team was successful in making the
math, science, and engineering curriculum more gender-neutral? Please explain your
answer with specific examples, if possible.
Very Inadequate
1
Poor
2
Fair
3
Good
4
Excellent
5
Please explain:
10. Do you have any additional thoughts about this year’s experience that you would like to
share with us?
Thanks for your help!
315
Contract for STEM Team Members
This contract describes the plan that STEM Team members will implement in an effort to
incorporate gender-equitable engineering concepts in their classrooms.
In the space below, please describe how you plan to integrate engineering activities in your
classrooms, including:
1. A timeline for the project, including estimated dates of implementation.
(When will you be going into the classrooms?)
2. The deliverables (activities, worksheets, or lesson plans) each STEM Team member will
complete as a part of this project.
3. The roles and responsibilities of the STEM Team members.
Contract Details:
316
Contract
We, the undersigned will incorporate the plan detailed above in this contract to the best
of our ability during the ________________ academic year.
Signed, STEM Team Members
Print Name
Role
(Teacher, Industry)
Signature
1. ______________
_________________ ___________________
2. ______________
_________________ ___________________
3. ______________
_________________ ___________________
4. ______________
_________________ ___________________
5. ______________
_________________ ___________________
6. ______________
_________________ ___________________
7. ______________
_________________ ___________________
8. ______________
_________________ ___________________
9. ______________
_________________ ___________________
10. ______________ _________________ ___________________
317
Title
Learning Strand:
Concepts:
Preparation Time:
Activity Time:
Level of Difficulty: (on a scale of 1 to 5, with 5 the most difficult)
Group Size:
Purpose
The purpose of this activity is …. In this activity, students will ….
Outcomes
By the end of this activity, students will be able to …..
Other skills practiced in this activity include …..
CONNECTIONS TO OVERALL CURRICULUM (if appropriate):
OVERVIEW OF THIS ACTIVITY: (Brief Summary)
Information needed to understand and teach activity. Should be easy to follow with subtitles for
easy reference to key concepts.
Subtitles
318
Subtitles
Materials
Items needed for activity.
For teachers. Be sure to highlight supplies and time needed for preparations.
Doing the Activity
For teachers.
Subtitles
Procedure
For students or for students and teacher.
Worksheets for Activity
For students. Should be in format that teachers can copy.
319
Conclusions
By the end of this activity, the students should ….. (A place for assessment tools.)
Vocabulary
New words used in activity
References
Web sites, books, articles
Extensions
Optional exercises that reinforce or extend the activity’s content but are not necessary to meet
the desired outcomes of the activity.
320

STEM Team - College of Engineering

Transcription

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