Name______________________________
Pendulum Activity
What affects the period of a pendulum?
Directions: Follow the following instructions and answer the questions.
Background: In this activity, you will be testing what variables affect the period of
the pendulum. You will be testing the release angle, varying the attached mass,
changing the length of the string, and theorizing how gravity affects the period. In
order to see what variable is affecting the pendulum, only one variable can be
changed at a time. Any more than one and we wouldn’t know what was causing the
change.
1. Make a simple pendulum. Tie a string to a horizontal bar and attach a mass
to the string.
2. Make a prediction of the variables you think will affect the period of a
pendulum.
Circle one or more of the following: (ANGLE, MASS, LENGTH, GRAVITY)
3. VARY THE RELEASE ANGLE: Use the stopwatch to time the period.
ANGLE (degrees)
Period of Time (seconds)
15
15
25
25
35
35
45
45
60
Does the period of time significantly change if you vary the angle?
4. CHANGE THE MASS: Use the stopwatch to time the period.
MASS (kg)
Period of Time (seconds)
Does the period of time significantly change if you vary the mass?
5. CHANGE THE LENGTH OF STRING: Use the stopwatch to time the period.
LENGTH (cm)
Period of Time (seconds)
Does the period of time significantly change if you vary the length?
6. Since we are stuck on the surface of the Earth, it’s impossible for us to test
changing the acceleration of gravity on the pendulum. Do you think gravity
would affect the period of a pendulum? Why?
Observations/Conclusions: Write a few sentences describing what you observed in
lab. Did your observations agree with your prediction? Describe why your results
were the same or different than your prediction. Make sure you include the
variables that you now think affect the period of a pendulum.