E 3.1.1.4 Engineering: A. Engineering Design

Transcription

E 3.1.1.4 Engineering: A. Engineering Design Process (EDP)
Activity: Eggbert
Science as Inquiry: As a result of activities in grades 5-8, all students should develop
• Understanding about scientific inquiry.
• Abilities necessary to do scientific inquiry: identify questions, design an investigation, collect and interpret
data, use evidence, think critically, analyze and predict, communicate, and use mathematics.
Source: National Science Education Standards
NSES Standards for Grades 5-8:
Science and Technology
•Technology influences society through
its products and processes. Technology
influences the quality of life and the ways
people act and interact. Technology changes
are often accompanied by social, political,
and economic changes that can be beneficial
or detrimental to individuals and to society.
Social needs, attitudes, and values influence
the direction of technological development.
•Science and technology have advanced
through contributions of many different
people in different cultures, at different
times in history. Science and technology
have contributed enormously to economic
growth and productivity among societies
and groups within societies.
•Scientists and engineers work in many
different settings, including colleges and
universities, businesses and industries,
specific research institutes, and
government agencies.
ISTE Standards:
Critical thinking, problem solving and
decision making.
Students:
•Identify and define authentic problems
and significant questions for investigation.
•Plan and manage activities to develop a
solution or complete a project.
•Collect and analyze data to identify solutions
and/or make informed decisions.
AAAS (2061) Benchmarks for
Grades 3-5 and 6-8:
•Clear communication is an essential part
of doing science. It enables scientists to
inform others about their work, expose their
ideas to criticism by other scientists, and stay
informed about scientific discoveries around
the world.
•No matter who does science and
mathematics or invents things, or when
or where they do it, the knowledge and
technology that result can eventually
become available to everyone in the world.
•Systems fail because they have faulty or
poorly matched parts, are used in ways that
exceed what was intended by the design,
or were poorly designed to begin with.
NCTM Expectations:
•Solve problems that arise in mathematics
and in other contexts.
•Apply and adapt a variety of appropriate
strategies to solve problems.
•Develop fluency in adding, subtracting,
multiplying, and dividing whole numbers.
•Select appropriate methods and tools for
computing with fractions and decimals
from among mental computation
estimation, calculators, and paper and
pencil according to the context and nature
of the computation and use the selected
method or tools.
•Factors such as cost, safety, appearance,
environmental impact, and what will
happen if the solution fails must be
considered in technological design.
•Scientific laws, engineering principles,
properties of materials, and construction
techniques must be taken into account
in designing engineering solutions
to problems.
•Models are very useful for communicating
ideas about objects, events, and processes.
When using a model to communicate about
something, it is important to keep in mind
how it is different from the thing
being modeled.
•Different models can be used to
represent the same thing. What model
to use depends on its purpose.
•Use multiple processes and diverse
perspectives to explore alternative solutions.
NETS for Teachers:
Teachers promote student reflection using
collaborative tools to reveal and clarify
students’ conceptual understanding and
thinking, planning, and creative processes.
1
Activity: Eggbert
Science Process Skills:
•
•
•
•
•
•
•
Observing
Comparing
Inferring
Predicting
Communicating
Designing
Constructing
Math Process Skills:
• Analyzing
• Comparing
• Computing
Objective:
The learner will recognize the engineering design
process is a method of problem solving used to create
a system, a product, or a process that meets an
identified need.
Time: 40–60 Minutes
Materials:
•
Launch Apparatus: 15–20 feet of string or
fishing line, cinder block or brick, one roll of
duct tape, large trash bag or tarp.
•
2 wire hangers
•
Ladder
•
Eggbert Glider (this can be either the
manufactured glider or wooden glider)
•
Eggbert Seats (1 per team) (1” × 2” piece of
pine, drill, hammer, nails, glue)
•
Eggs (1 per team)
•
Materials for students to purchase for
designing restraint system: Plastic bags,
rubber bands, string, cotton balls, clay, foam
pads, toilet paper, masking tape.
•
Student booklet
•
Pencil
•
Markers
2
Activity: Eggbert
Instructor Preparation :
Eggbert Activity
Make the glider and seats. This can be either the manufactured
glider or a wooden glider.
Set up the launcher apparatus by tying the glide path line to the
ceiling and the top of the cinder block or brick. Place the block
on the floor across the room so that the line descends at
approximately a 45° angle.
Put plastic tarp or large trash bag under and around the block.
Prepare materials for each group to purchase when designing the
restraint system. You might want to put materials in bags for each
team so they can decide what to purchase. Or, you may choose to set
up a store where teams can purchase materials.
Have eggs available for distribution.
3
Activity: Eggbert
Instructor Background Information:
Key Vocabulary
Inertia—the tendency of
an object to resist a change
in motion. An object at rest,
will remain at rest unless a
force acts on it. An object in
motion, will continue in the
same direction at the same
speed, unless an outside
force acts on it. Newton’s
First Law of Motion deals
with inertia.
Momentum—the product
of an object’s mass and
velocity, which determines
how difficult it is to stop the
object’s motion.
What Is the Engineering Design Process?
The Engineering Design Process is a series of steps that aid in the
design of an effective solution for a given problem. Engineers use
different versions of the steps. Here is one example of the steps
of the process:
• Define • Research
• Develop
• Choose
• Create
• Test and Evaluate
• Communicate
• Redesign
Define
the Problem
Force—a push or a pull
that gives energy to an
object, sometimes causing
a change in the motion of
the object.
Engineering Design
Process—a cyclical method
of problem solving used to
create a system, a product,
or a process that meets an
identified need.
Potential Energy—energy
that is stored within an
object, not in motion but
capable of becoming active.
2
8
Acceleration—a change
in velocity (speeding up or
slowing down).
Research
Redesign
the Problem
3
7
Communicate
Develop
Possible Solutions
1.
2.
3.
4.
5.
Option One
O p t i o n Tw o
Option Three
Option Four
Option Five
6
4
Test &
Evaluate
Choose
the Best Solution
5
Create
Kinetic Energy—energy
in motion.
a Prototype
4
Activity: Eggbert
Define: The Engineering Design Process always begins with a
need, or a problem that must be solved. It may also involve an
improvement to an existing design. The main challenge at this
point is to define exactly what the need is, including any specific
requirements. A complete understanding of the need will make the
solution easier to design.
Research: Once a need has been established, the next step is to ask
questions about the nature of the problem and to do any necessary
background research. Other people may have tried to solve a similar
problem in the past. Engineers may incorporate past work into their
own design process, but they must be careful to not use someone
else’s idea without permission.
Develop: This is essentially the brainstorming phase of the process,
which gives engineers a chance to be creative. It’s important to
remember that there may be more than one solution to a problem,
and, in many cases, there are multiple solutions. Once a list of ideas
has been generated, the engineers can select the most promising
idea to work on.
Choose: Planning involves taking an idea and filling in all the details
that will bring the idea to life. While developing the idea, engineers
will break the design into smaller parts to determine exactly how
each part will function, draw diagrams, and compile a list of necessary materials. As they develop their solutions, engineers often call
on their own knowledge of math and science, but they may have to
do additional research to complete their design.
Create: After the planning stage is complete, engineers build a prototype of their design, then come up with effective ways to test it.
Test and Evaluate: Once the design has been tested, they use the
results as a basis for possible improvements. Engineers examine
what worked, what didn’t work, and what could work better.
Communicate: In this stage, engineers use this data from their tests
to make improvements on their design. This is also a good time for
peer review and feedback.
Redesign: Upon receiving feedback, engineers may make further
improvements on their design until they are satisfied with the final
version. The process seems linear, but in practice, the steps may
blend into each other, occur out of order, or repeat several times.
Engineering is the process of trying, creating, testing, and then
re-trying until the design works. It can be a lengthy and drawn-out
process, and it is rare that a design works perfectly the first time.
5
Activity: Eggbert
Vehicle Restraint Systems
For this activity, students will be designing restraint systems to
keep Eggbert from cracking. These systems may (or may not!)
be similar to some of the current restraint systems that are
commonly used in modern vehicles, such as airbags, seat belts,
and harnesses.
Airbag = passive restraint system
Seat belt = active restraint system
Airbags are known as a “passive restraint” system, which may
sound confusing since most people do not think of airbag
deployment as a “passive” event. They are designated as “passive”
because airbag deployment requires no action on the part of
the user. Airbags will deploy automatically in the event of a
collision that meets a pre-programmed set of specifications
(speed, deceleration, angle of impact). Many modern cars contain
front and side airbags for both the driver and front passenger
of the vehicle.
Airbags were originally designed as an alternative to seat belts,
but in reality, they do not provide the same protection. In a
collision, the airbag can cause as much injury as other parts of
the car to those who do not wear seat belts. Airbags deploy and
deflate faster than the blink of an eye (about 1/20 of a second).
Occupants should always wear seat belts, and drivers should sit
at a reasonable distance from the steering wheel. Some modern
airbags have sensors that detect the size and weight of an
occupant and adjust the force of the airbag deployment
accordingly. However, many vehicle manufacturers recommend
that small occupants, such as children, remain in the back seat.
Seat belts, the primary restraint system in most vehicles, are still
regarded as the most effective form of restraint. Unlike airbags,
seat belts are “active restraint” systems, because they require the
user to actively attach the seatbelt before driving. There are three
main types of seat belts in modern cars:
• lap belts
• shoulder belts
• three-point belts
Three-point belts combine the best features of lap and shoulder
belts, and they are generally considered the safest form of
restraint, because they hold the occupant securely in the seat
and, in the event of a collision, evenly distribute the force
between the occupant’s chest and hips.
6
Activity: Eggbert
Many seat belts also have additional features to increase safety.
A common feature is the inertial lock, which automatically locks
the seat belt if it is jerked forward quickly (as in a crash). Another
feature (designed for forgetful drivers) is the automatic seatbelt.
In most of these cases, the occupant is still required to manually
put on the lap belt, but the shoulder belt will move along a track
and fasten into place once the car is turned on.
Some variations on the seat belt include the five-point belt,
which is usually used in infant car seats, and the six- and sevenpoint belts, which are often used by race car drivers. Other
variations can be found in vehicles other than cars. Planes, for
example, still use only lap belts for their passengers. Roller
coasters usually use either over-the-shoulder restraints (for
inverted rides), or lap bars, which are designed to be loose
restraints so as to increase the sense of “danger.”
7
Activity: Eggbert
Lesson
Mission
Eggbert has volunteered for the first egg-head mission to
the Moon. The dilemma Eggbert faces is that the landing
on the Moon’s surface will be very quick, and the glider
will crash. To ensure the success of this mission, your
engineering team will need to design a safety restraint
device that will withstand the crash.
Note:
Explain to the students that
in real life, cost is a factor that
engineers must take into
account as they work on
solutions. For this activity,
they must restrain Eggbert
using only limited supplies in
their budget.
Your team has a budget of $800.00 to spend on the
materials for the design. Each item has a limit (x) and a
cost. You must discuss what materials you will purchase,
keeping within your budget, and record the items in a
spreadsheet. You must also ALL agree on a team design.
If Eggbert does not survive your first attempt, you may have
time to redesign the restraint system. You might want to
consider saving some money for a redesign.
Happy Designing!
Introduction: Engineering Design Process
Strategic Questions:
What does an engineer do?
What steps does an
engineer take to solve
a problem?
Lead students to define an engineer as someone who solves
problems by developing new or improving existing products or
ways of doing things. Someone who solves problems for a living
must have a problem-solving method. Engineers have followed
the same basic method or process for thousands of years.
The process is:
a. Define the problem
b. Research the problem
c. Develop possible solutions
d. Choose the best solution
e. Create a prototype
f. Test and evaluate the prototype
g. Communicate results
h. Redesign if necessary
* Go through process again (Repeat)
8
Activity: Eggbert
Walk students through an example of engineering a product
—such as a toothbrush—so they can understand the steps in
action. PTC software designed the Braun toothbrush.
Define the problem:
People need to have a device to apply toothpaste to
their teeth to remove plaque and germs.
Research the problem:
Look up what other people use, study other
toothbrushes, study plaque accumulation on teeth, etc.
Develop possible solutions:
Brainstorm everything you can think of related to
brushing teeth; every bristle configuration,
construction material, length, width, etc.
Choose the best solution:
Out of all the ideas, choose one or a combination of
several that you think would work the best.
Create a prototype:
Make a model of the design you have chosen.
Test and Evaluate:
Use the model and complete several tests. Use the
model several times and assess the results. What
worked well and what needs improvement?
Communicate:
Discuss the results with others and brainstorm
solutions to problems and possible improvements.
Perhaps the tests showed that your back teeth were
not getting clean enough, but it was difficult to
position your hand in a way that the toothbrush could
reach those teeth adequately. You decide to bend the
handle of the toothbrush to angle it to reach your back
teeth better.
Redesign:
You decide to start the process all over again to make
a new prototype with the angled handle.
*Define the problem:
Now you have a new problem: How do I angle the
toothbrush to get maximum cleaning of the back
teeth? The process continues.
9
Activity: Eggbert
Note:
As students discuss
various kinds of seat
restraints, encourage them
to think about how the
restraints they have seen are
different. Have them consider
why a restraint might have
been designed a certain way.
Explain that the Department of Defense has hundreds of
engineers working on devices to make military equipment
safer. The students will apply their knowledge of the
engineering design process to design a safety restraint device
for Eggbert’s glider, just like a DoD engineer would do.
Have students discuss their prior knowledge of seat restraints,
whether in cars, planes, amusement park rides, or child seats.
Remind them that this knowledge may be useful to them as
they complete their designs.
The Design Process Steps A through E
Strategic Questions:
What forces can you
identify that will be in
operation and will act
on the glider?
(potential energy, kinetic
energy, gravity, friction,
the cinder block)
What forces can you
identify that will be in
operation and will act
on Eggbert?
(potential energy, kinetic
energy, gravity, friction,
the cinder block, and
the restraint system if
designed properly)
Introduce students to Eggbert and display his glider and seat.
Demonstrate how the glider will be traveling and crashing, where
the seat will be located, and how the seat attaches to the glider.
Pass out an egg, a seat, and a bag of materials to each group of
four students (or have students purchase from store after design
is completed). Give the groups 5 to 10 minutes to discuss their
design plans, working through Steps A to E in the Engineering
Design Process. Students must also write their purchases in the
spreadsheet. After groups decide on prototype designs, allow
them several minutes (determined by your number of groups and
schedule) to construct their restraint systems. Remind them that,
time permitting, it may be necessary to redesign.
E 3.1.1.4 Engineering: A. Engineering Design Process (EDP) 10
Activity: Eggbert
Items:
Plastic bag (2) $120.99 ea.
Rubber band (2) $99.35 ea.
String (3) $49.12 ea.
Cotton ball (2) $101.26 ea.
Clay (1) $98.98 ea.
Foam (1) $96.03 ea.
Square of toilet paper (3) $48.05 ea.
Sample spreadsheet:
Item
Cost
Quantity
Total
Every team gets one free 30-cm
piece of masking tape
Activity: Eggbert
The Design Process Steps F through H
Test each crew’s system by sending the glider down the wire.
Check for understanding by discussing the results of
each landing.
4
Check for Understanding:
Which restraint systems were successful in protecting Eggbert from injury? Which systems were not?
Why or why not?
Have students discuss possible improvements to their designs.
4
Check for Understanding:
What is the next step in the Engineering Design
Process? (redesign)
How can the unsuccessful design be altered to ensure
Eggbert’s safety? (answers will vary)
How can the successful designs be improved? (make
more comfortable, make design more appealing,
use fewer materials to reduce cost, etc.)
After the discussion and debrief, challenge the design team to
redesign the prototype to get better results.
Distribute achievement certificates to the groups that were able
to successfully keep the egg from breaking.
Activity: Eggbert
Suggested Final Assessment Questions
Apply knowledge
1. Why are airbags not meant to replace seat belts?
Possible answer: Air bags are dangerous. If a person in a crash
wasn’t wearing a seat belt, inertia would cause the person to
fly into the airbag, which could cause injury.
Evaluate
2. Imagine you are designing a restraint system for a real
person (not an egg). What are additional factors that you
would have to consider?
Possible answer: The restrained person would still have to
have some freedom of movement.
Analyze information
3. Why is it important to plan a design carefully before you
build it?
Possible answer: If you build without planning, the design is
more likely to have problems. Planning first can save time
and money.
Knowledge Application
4. A car manufacturer designs, builds, and sells a car model.
What step of the design process has the manufacturer
forgotten? Why is this step important?
Possible answer: The manufacturer forgot to test the car
model. Without testing, there is no way to know if the car will
work properly, or if it is safe.
Activity: Eggbert
Suggested Final Assessment Questions
1. Why are airbags not meant to replace seat belts?
2. Imagine you are designing a restraint system for a real person (not an egg). What are additional factors that you would
have to consider?
3. Why is it important to plan a design carefully before you
build it?
4. A car manufacturer designs, builds, and sells a car model.
What step of the design process has the manufacturer
forgotten? Why is this step important?
Eggbert Activity Assessment
Activity Log
1. Sketch and label the parts of your team’s design.
2. How well did your design work? Circle the condition of Eggbert after launch.
Survival (no damage)
Living…with cracked skull (shell cracked)
Unconscious with brain damage (yolk broke)
Totally scrambled (everything is broken)
3. How could your group modify your design to make it better?
4. How did your group work as a team? What was the most difficult part?
Eggbert Activity Answer Key
This space should contain a drawing of the group’s seat design, including labels of
the parts where appropriate.
2. How well did your design work? Circle the condition of Eggbert after launch.
Survival (no damage)
Living…with cracked skull (shell cracked)
Unconscious with brain damage (yolk broke)
Totally scrambled (everything is broken)
Students should circle the relevant condition of the egg after their first launch.
3. How could your group improve or modify your design?
1. Sketch and label the parts of your team’s design.
Activity Log
Students should include suggestions of modifications they could make to their design.
4. How did your group work as a team? What was the most difficult part?
Students should include comments evaluating their work as a team. The answer should
include what they thought was the most difficult part.
Activity: Eggbert
Making the Manufactured Glider
To make the glider
1.Individually load the four STL files for the Eggbert Glider
(GliderFuselage, GliderNose, GliderSeat, and GliderTail) in the
Catalyst software.
2.Make certain to set the layer Resolution to 0.010 and the
Printer Interior Style to Solid-Normal.
3.Orient the model onto the base.
4.Print the models.
Making the Wooden Glider
To make the glider
1.To construct Eggbert’s glider, begin by photocopying the
Eggbert glider template.
2.Cut out the patterns, arrange them on the 12” x 13” pinewood
board, and trace their outlines. When arranging the “Base”
and “Nose (Part A)” patterns, align the pieces by putting them
together at the dashed lines. 3.With a jigsaw, cut the patterns from the board.
4.To attach part B of the nose, apply glue to one side of part B
and match it up with part A of the nose. (You can use either
side of the glider’s base, but whatever side you select, this
will be the topside of the lander.) Strengthen the fit by
driving two nails through parts A and B of the nose. (Again,
to prevent wood splits, it is worth taking the time to drill the
holes for the nails first.)
5.Smear glue along the bottom edge of the tail and align it
along the center of the base. Reinforce the attachment by
driving two nails from the underside of the base into the tail.
Activity: Eggbert
6.Check the fit of the seat assembly between the tail and part
B of the nose section. If the fit is too tight, shorten the seat
base by sanding or cutting its front edge. Once you establish
a good fit, mark the location of the hole for the bolt onto the
glider’s base. Drill a hole through the base of the glider with
the same bit used to drill the hole through the seat.
7.Cut two 6-inch lengths from the wire coat hanger. Fashion
a hook-like loop on one end of each wire and bend the hook
to a 90-degree angle. (The #12 x 1” wood screw will fix the
wire to the underside of the glider’s base. The loop, therefore,
should be large enough to accommodate the screw’s shaft
but, at the same time, small enough to keep the head of the
screw from slipping through.)
8.Drill two narrow holes for these wires. Drill the first through
the tail and glider base, and the second through parts A and
B of the nose.
9.Entering from the underside of the base, slip the wires
through the holes. Anchor the wires to the base using the
#12 x 1” wood screws.
10. Twist the top of the hanger wires into a loop as shown
on page 22. This will prevent the glider from skipping off the
fishing line at impact. You can easily make the twist using a
pair of regular or needle-nose pliers.
11. As a bumper to preserve the longevity of the glider, glue
or nail the plastic strip along the front edge of the nose.
12. Slip the 5/16” x 2” bolt through the hole in the seat base.
Apply a generous amount of wood glue over the head of
the bolt and allow it to dry thoroughly before use.
13. To improve the attractiveness of the glider, you may elect
to paint or decorate it.
Activity: Eggbert
To make the seats
1.Use the templates to cut two pieces from the 1” × 2” pine
wood. The base of the seat should be significantly longer
than the back.
2.Glue the end of the base to the bottom edge of the back,
forming a seat. Hammer nails through the other side of the
back to secure the base.
3.Drill a large hole 1” from the far edge of the base. This should
correspond to the large hole you drilled in the main
glider piece.
4. To attach the chair to the glider, insert a bolt through the
large holes in the seat and base (the two holes should line up),
and secure it from the other side with a wing nut. Each
individual seat can be attached and removed from the
glider this way.
5.Make enough seats for each group in the class to have one.
6.Set up the launcher apparatus. Use a ladder to tie the
upper end of the glide path line (string or fishing line) high
enough so that the line runs at about a 45° angle down to the
cinder block on the floor. The length of the string should be
about 15 to 20 feet, so the upper end should be tied between
10 and 14 feet off the floor. Modify height as needed for
lower ceilings.
7.Set up a large trash bag or two under the cinder block, as this
activity may become messy.
8.Prepare a complete set of supplies for each group to use
to use in its restraint system.
Glue
1/4” aluminum
rod cut to
22-mm length
EGGBERT‛S GLIDER
Insert seat into
slot and push
forward to lock
into place
Glue nose
onto fuselage
Good Luck!
Glue tail
onto fuselage
Develop a hanging system of your own.
These holes are designed to accept a
#8 eye bolt.
Activity: Eggbert
Base
(Part B)
Nose
(Part A)
Nose
EGGBERT‛S GLIDER (wooden version)
Tail
apply glue to
underside and
nail base to tail
drill hole through
tail and glider base
for wire
anchor wire loop
with screw
drill holes
for bolt
6” length of
clothes hanger wire
form a loop on
the wire hanger
affix to nose
apply glue to
underside and
nail to nose
drill hole
through nose
for wire
EGGBERT‛S GLIDER (wooden version)
nail seat back
to base
bend loop to 90°
angle and anchor
to base with screw
drill hole 1.5”
from edge
Activity: Eggbert
Eggbert Certificate
Helped save Eggbert by using the Engineering Design Process.
The team designed a restraint system within budget that
allowed Eggbert to land safely.
Eggbert Certificate
Helped save Eggbert by using the Engineering Design Process.
The team designed a restraint system within budget that
allowed Eggbert to land safely.
Activity: Eggbert
Resources
Sources:
Eggbert is copyrighted by Melko, 1989.
http://www.iihs.org/research/qanda/airbags.html
http://www.nhtsa.dot.gov/people/injury/airbags/airbags03/page3.html
http://auto.howstuffworks.com/seatbelt.htm
http://inventors.about.com/library/inventors/bl_seat_belts.htm
http://www.nationmaster.com/encyclopedia/Automatic-seat-belt
http://science.howstuffworks.com/roller-coaster9.htm
http://www.ptc.com

E 3.1.1.4 Engineering: A. Engineering Design

Transcription

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