The Mad Scientist

Pendulums:

Does Amplitude affect Frequency?


In the last experiment, we looked at the patterns that could be made by a pendulum. In this experiment, we will try to answer the question, "Does the amplitude of the pendulum affect its frequency?" As we will find out, the answer explains why the pendulum is useful as a clock!

Materials:

 Pendulum support  paper clip

 1" wooden bob  halved golf tees
 string  ruler
 strips of paper

Procedures and Observations:

1. Attach the wooden sphere to the paper clip on the pendulum. Mark the paper strip to show 0 cm, 5 cm, 10 cm, 15 cm, 20 cm, 25 cm, and 30 cm. Place this paper rule (at 0 cm) directly underneath the resting bob. Tape the paper rule to the floor or table top. Pull the bob back to the 25-cm mark (pull back distance). Make sure the center of the bob is over the marker on the paper strip. With your partner, predict how many cycles your pendulum will make in one minute (the frequency). Record your prediction. Next, release the bob and count the frequency (number of cycles per minute). Record this number as your actual observation.

2. Repeat this experiment four more times for the remaining marks on your strip (20 cm, 15 cm, 10 cm, and 5 cm). These will be your new selections for amplitude. Remember to record your predictions first. Record the actual frequency.

3. Study the data to explain whether amplitude affects the number of cycles per minute or frequency. Write a summary sentence in your science journal and be prepared to discuss your findings with the class.


 


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