Testing Variables With Fingerboards

Transcription

Testing Variables With Fingerboards
Testing Variables With
Fingerboards: What Is the Fastest
Speed a Fingerboard Can Attain
When Launched From a Ramp?
We have been studying aspects of force and motion –
specifically, speed and what conditions can affect it. We have
also spent time learning how to control and test variables using
fair tests. Your team will be conducting several different tests in
order to answer this question: What is the fastest speed a
fingerboard can attain when launched from a ramp?
With this question as your guide, you must come up with a
procedural design and a method that will generate reliable
data. You will need to conduct separate tests related to (1) the
angle of the ramp and (2) the mass of the board, in order to
determine how they affect the speed of the fingerboard. Then,
you must analyze and synthesize data from all tests to state
your conclusions.
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Testing Variables With Fingerboards: What Is the Fastest
Speed a Fingerboard Can Attain When Launched From a
Ramp?
Suggested Grade Span
6–8
Task
We have been studying aspects of force and motion – specifically, speed and what conditions
can affect it. We have also spent time learning how to control and test variables using fair tests.
Your team will be conducting several different tests in order to answer this question: What is the
fastest speed a fingerboard can attain when launched from a ramp?
With this question as your guide, you must come up with a procedural design and a method that
will generate reliable data. You will need to conduct separate tests related to (1) the angle of
the ramp and (2) the mass of the board, in order to determine how they affect the speed of the
fingerboard. Then, you must analyze and synthesize data from all tests to state your
conclusions.
Big Ideas and Unifying Concepts
Cause and effect
Change and constancy
Design
Form and function
Physical Science Concept
Motion and forces
Design Technology Concepts
Design constraints and advantages
Invention
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Mathematics Concepts
Algebra
Data collection, organization and analysis
Graphs, tables and representations
Measurement
Time Required for the Task
About one week of class sessions of 40-minute periods (to test all variables, analyze data and
draw conclusions).
Context
My students had been studying force and motion, specifically speed. Finger skateboards had
been especially popular all year (and in fact had been banned from the class for creating a
disturbance!). Since several teacher resources suggested similar investigations using
“matchbox” cars, we thought this would be an opportunity to trade on student interest to create
buy-in for the investigation. In fact, there were enough students who owned these “Teck-Dec”
fingerboards that it wasn’t necessary for me to buy any. Several students had already created
small ramps for playing at home and brought those in to begin the investigations.
What the Task Accomplishes
I wanted this to be an assessment investigation where I only gave the students a general
question and left the procedural design completely up to the groups. It required lots of false
starts and group discussions before students found a method that worked to generate some
reliable data. Students were challenged to conduct tests on different variables in order to make
some generalized statements about how the variables collectively affected the optimum speed
of the fingerboards. Students also used a variety of methods and math skills in finding the
measure of or calculating the ramp angles, distances and changes in mass.
How the Student Will Investigate
Students were left pretty much on their own to come up with investigative methods, ramp
designs and materials choices. It took a couple of class periods of trying out a variety of
methods before data collection actually began. The teacher’s role was to stand back and
observe rather than get involved with suggestions to move the process along. This is an
excellent opportunity for teachers to collect anecdotal assessment information about how
students apply scientific processes and reasoning as they work.
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Interdisciplinary Links and Extensions
Science
Test results with fingerboards by using matchbox cars and compare performance and designs.
Students could change the ramp surfaces and run trials again, comparing results in order to
increase speed.
Language Arts/Music
Students could write advertisements, raps and/or jingles for their high-performance ramps.
Technology
Students could create animations to show fingerboards in action.
Mathematics/Design
Draw scale diagrams of the various ramps in lab reports, so that someone else could recreate
your setup and thereby recreate your data sets.
Teaching Tips and Guiding Questions
I advise issuing the challenge to design the ramp and then giving plenty of time for exploration
before intervening with questions or suggestions. Remind students that their design needs to be
reproducible by others with only the lab reports for resources. Therefore, students need to be
meticulous in describing the materials and their setups. They need to control all variables other
than the one being tested.
Some guiding questions to ask students after they have had time to become fully involved in
their investigations might include:
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What have you learned so far that will help you make predictions or conduct your next test?
Which variables will you control?
What variable will you test? How will you make it a fair test?
What materials and tools do you need?
How will you record your data? How will you display your data?
How will you know if you need to make any changes in your methods?
Are your procedures clearly written so that someone else can repeat the investigation to
get similar results?
Can you apply any mathematics concepts to your data analysis?
What do your results tell you? What did you learn from your results?
What conclusions can you make based on your results?
Do you think what you learned is always true of speed?
What new questions do you have? What further tests could be run?
Have you learned anything that surprised you?
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Concepts to be Assessed
(Unifying concepts/big ideas and science concepts to be assessed using the Science
Exemplars Rubric under the criterion: Science Concepts and Related Content)
Physical Science – Motion and Forces: Students observe and investigate the relationships of
speed, slope and mass of the object in motion. They observe that an unbalanced force acting
on an object changes its speed or path of motion or both. Students understand that speed is a
measure of distance over time and that a ramp built on a very steep angle may generate high
speed, but that speed cannot be maintained beyond the end of the ramp as the board will crash
into the floor rather than be propelled along the flat surface.
Design Technology – Invention: Students create the ramp that will provide the fastest speed of
the fingerboard launched from it. Several steps are involved in making things. Students test
results to provide information for design modifications.
Design Technology – Constraints and Advantages: Students recognize constraints in the
classroom and in the materials available. Materials and designs need to be accurately
described in order to be recreated by someone using the written description. Students
understand that some materials are better than others depending on the task and the
characteristics of the materials.
Scientific Method: Students determine the patterns and/or which kinds of change are
happening by making a graph or table of measurements (change-constancy). Students observe
and explain reactions when variables are controlled (form and function). Students understand
the interdependence of variables in the investigation and how mass and the angle of the ramp
are related to the speed of the fingerboard (mechanical systems).
Mathematics: Students identify trends and patterns and represent and analyze data
appropriately. Students use tables and graphs to show how values of one variable are related
(increase, decrease, etc.) to values of another. Numerical data and precise measurements are
used in describing events, answering questions, providing evidence for scientific explanations
and challenging misconceptions. Students apply the concept of algebra.
Skills to be Developed
(Science process skills to be assessed using the Science Exemplars Rubric under the criteria:
Scientific Procedures and Reasoning Strategies, and Scientific Communication Using Data)
Scientific Method: Observing, predicting/hypothesizing, collecting/recording data, manipulating
tools, drawing conclusions, communicating findings, challenging misconceptions and raising
new questions.
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Other Science Standards and Concepts Addressed
Scientific Method: Students describe, predict, investigate and explain phenomena. Students
control variables.
Scientific Theory: Students look for evidence that explains why things happen and modify
explanations when new observations are made.
Physical Science – Motion and Forces: Students observe and record the effects of ramp slope
and mass on speed.
The Designed World: Student observe that tools extend the ability of people (to make things,
to move things, to shape materials) and that manufacturing requires a series of steps and,
depending on the task, a careful choice of materials (based on their characteristics).
Scientific Tools: Students use computers to organize, analyze and interpret data.
Suggested Materials
Fingerboards can be purchased at toy stores and hobby shops. A variety of boards may be
provided, or students can bring in their own. Groups will need stopwatches, meter sticks,
measuring tapes, boxes or books (for raising the heights of ramps) and masking tape. My
students used nickels to add mass (other coins or washers would also work) and borrowed a
carpenter’s level from the Tech Ed teacher to assist in measuring the angle of the ramps.
Possible Solutions
Students need to use their data to answer the question: What is the fastest speed a fingerboard
can attain being launched from a ramp? In order to do this, the task needs to be broken down
into parts for testing variables:
Part 1: How does the angle of the ramp affect the speed of a fingerboard?
Part 2: How does the mass of the board affect the speed?
Students were expected to follow the “Lab Report Format” required at our school. Several
different variables should have been tested, and students should have data-recording tables,
data analyses, graphical representations of data analysis, and a written discussion that
analyzes data collected. Specific data figures will vary with different ramps and fingerboards
used; however, there should be several general trends revealed in the data.
Students should discover that a ramp angled slightly less than 45 degrees will give the
fingerboard the best start to continue running once it levels off onto a smooth surface. For our
class investigations, it seemed that due to experimental errors of fingerboard wheel design, it
was difficult to determine an ideal number of nickels to create the optimum momentum. The
boards seemed to achieve just as high speeds with no added mass.
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Task-Specific Assessment Notes
General Notes
We have included student work at each performance level for all parts of this investigation,
rather than in separate parts (i.e., Part 1 and Part 2) as we often do. This makes the work
samples here rather long, and a bit more complex to assess at first glance. Because students
needed to gather all of the data and synthesize their information into one conclusion, it seemed
appropriate to keep the various parts together.
Novice
This student’s solution is incomplete and lacking in details. The materials list is vague and no
purpose is stated at the beginning of the investigation. The drawings are unclear and somewhat
confusing. This student does not demonstrate the use of tools to gather data in a scientific
manner. There is no evidence of repeated trials for gathering accurate data. The strategy is
very sketchy, showing little evidence of scientific reasoning being used. There is little gathered
data, resulting in a very weak data analysis. It would be almost impossible for anyone to
recreate this investigation based on this student’s procedures. Conclusions make only general
references to how mass and height of ramp could affect speed and do not refer to trends in
data to achieve optimum speed. The student’s one attempt to make a reference to a “big idea”
of science in the concluding paragraph shows a lack of understanding of the main scientific
concepts being investigated.
Apprentice
Although the task is completed, this student’s solution is lacking in detail. There is some
evidence about how the student conducted the investigation and the reasoning behind
conducting it. The explanation is incomplete, lacking some of the steps of the test(s) conducted.
There is no diagram of the ramp setup, so it would be almost impossible to recreate the
student’s investigation. It appears that only one trial was conducted under each condition,
resulting in unreliable data. These data are displayed poorly in working charts, making it difficult
to interpret the findings. Some chart headings and measurement units are omitted. The student
shows a lack of conceptual understanding in both the conclusion and significance sections of
the lab report. Conclusions do not consider experimental errors, possible improvements or
alternative hypotheses.
Practitioner
This student’s solution is complete. The original problem statement was well-written in that all
necessary parts of the lab report are present. It is easy to understand the basics of what was
done to conduct the investigation, as both the written procedure and diagrams enhance that
understanding. The student organizes the resulting data very well. Unfortunately, there are data
from only one trial under each condition of the investigation, making results questionable. The
student applies excellent scientific and mathematical skills to convert units of measure through
dimensional analysis and applies trigonometric functions to determine the ramp angle. The
student uses an assortment of graphical representations to display the data and has reasonable
conclusions. The student is able to relate the investigation to the in-class learning by
demonstrating recognition of the major concepts and theories being studied.
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Expert
This student’s solution is complete and detailed. The original problem statement is well-written
in that it considers the variables independently. There is evidence of use of prior knowledge and
experience about speed demonstrated in the hypothesis. The procedure is clear and there is a
well-labeled diagram of the ramp apparatus. More than one representation is used to display
data. There are well-organized data tables and graphical analyses of those data. The computergenerated graph is an accurate, appropriate representation of data. There is clear evidence of
scientific reasoning in the written data analysis, showing deep understanding of the
shortcomings of the design technology and subsequent results. Conclusions are supported by
data. There is evidence of extended thinking again in the data analysis and conclusion
paragraphs.
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Novice
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Novice
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Novice
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Novice
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Novice
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Apprentice
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Apprentice
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Apprentice
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Apprentice
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Apprentice
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Apprentice
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Apprentice
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Practitioner
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Practitioner
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Practitioner
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Practitioner
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Practitioner
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Practitioner
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Expert
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Expert
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Expert
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Expert
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Expert
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Expert
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