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4th Grade Performance Task
Contributed by: Kentucky Department of Education (KDE)
Performance Events 1993-94
Description:
Students will experiment with a pendulum to find out
why it might swing at different speeds at different times.
This task is designed to take approximately 30 minutes.
Materials:
- Information sheet
- Three weights
- Pencils
- Three wires
- Bar
Group Activity:
Marcia and Kevin were swinging on the playground. They timed their
swings and found that Kevin made more swings in 15 seconds than
Marcia did. Why would that happen? Was it a difference in their
weights? Were their swings different in length?
Your job is to experiment with the pendulum at your table to find
an explanation for why Marcia and Kevin were swinging at different
rates.
First read the sheet at your table called "Information
Sheet-How to Use the Pendulum."
DO NOT CONTINUE UNTIL YOU HAVE READ THIS SHEET.
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Experiment with the pendulum by doing the tests described. There
are two variables you will change as you work. (Things that
can change are called variables.) The variables are length
of the wire and weight of the bob.
You will change only one variable at a time. Each time
you change a variable. YOU COUNT THE NUMBER OF COMPLETE SWINGS THE
PENDULUM MAKES IN 15 SECONDS. Do each test twice (Trial 1 and Trial
2). Each member of the group should record the results of the tests
in the tables below.
- Use the charts below to record your measurements. Always give
the number of COMPLET SWINGS THE PENDULUM MAKES IN 15 SECONDS.
| VARIABLE 1: USING DIFFERENT LENGTHS
(Use only the largest weight.) |
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Long Wire
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Medium Wire
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Short Wire
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Trial 1
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Trial 2
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| VARIABLE 2: USING DIFFERENT WEIGHTS
(Use only the longest wire.) |
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Large Weight
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Medium Weight
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Small Weigth
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Trial 1
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Trial 2
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- Work together as a group to study your results. Then write what
the group thinks is the reason Marcia and Kevin did not swing
at the same rate.
Individual Activity:
- What happened to the rate the pendulum swung when you changed
the length of the wire?
- What happened to the rate the pendulum swung when you changed
the amount of weight that was swinging?
- Which variable most affected the number of swings in 15 seconds?
- If Marcia and Kevin wanted to be sure that they would swing
at almost exactly the same rate, what thing or things would they
have to change before they tried swinging again?
- The pendulum system is a model of the swing system. Compare
the parts of the two systems.
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