PALM - Task with Student Directions

Elementary Task
Contributed by: Council of Chief State School Officers (CCSSO)

A pendulum is a weight attached to a string that can swing back and forth. Maria was playing on the playground at school and noticed that swing sets work like pendulums. After a classmate on a swing was pushed, she noticed that the amount of time it took for the classmate to swing out and back did not seem to change. She decided to do some experiments using the swing set below:

Experiment 1
One of her classmates sat in Swing A. Maria pulled the swing back as far as she could and then let go. She timed the number of swings that occurred in 60 seconds. Maria repeated this procedure with Swings B and C. She recorded the results in Table 1.

Experiment 2
Maria repeated Experiment 1, but this time she measured the time it took for the classmate to swing back and forth 20 times. The results are shown in Table 2.

1. In which of the following ways was the procedure in Experiment 1 different from the procedure in Experiment 2?

A. In Experiment 1, the length of each swing was different. In Experiment 2, the length of each swing was the same.

B. In Experiment 1, the length of each swing was the same. In Experiment 2, the length of each swing was different.

C. In Experiment 1, the number of swings in a certain time was measured. In Experiment 2, the time for a certain number of swings was measured.

D. In Experiment 1, the time for a number of swings was measured. In Experiment 2, the number of swings in a certain time was measured.

2. Experiment 1 was repeated, but instead, the number of swings that occurred in 30 seconds was timed. How many swings would you predict occurred in Swing B in 20 seconds?

A. 8
B. 10
C. 18
D. 20

3. Experiment 2 was repeated with a fourth swing that was 160 centimeters in length. The time it took for the classmate to swing 20 times would be closest to:

A. 66 seconds
B. 60 seconds
C. 55 seconds
D. 50 seconds

4. Students measured the time it took pendulums (balls attached to strings) of different lengths to swing back and forth 10 times:

If students had measured a pendulum 7 centimeters in length, the time for 10 complete swings would have been closest to:

A. 3 seconds
B. 5 seconds
C. 7 seconds
D. 9 seconds

5. The period of a swing (pendulum) is the amount of time it takes for the person swinging to swing out and back. Use the result of Experiments 1 and 2 to explain how the length of the swing affects the period of the swing.

6. Write down two things you've seen (other than a playground swing) that work like a pendulum and explain why. Describe what part of the object acts like the string and what part of the object acts like the weight in a pendulum.