Extra Credit: The Pendulum

How does the period of a pendulum depend on its length?

This project may be done by teams of 1-2 individuals. You must design a device which can be used as a pendulum; the device must be adjustable so that its overall length can be varied over a range which starts around 20 cm and goes to at least 100 cm. The device must be hung from the same point of attachment each time, and must have very little material above the point of attachment. A single meterstick with a number of holes in it is not a good device for this project. Draw a picture or two of your device, showing it at its maximum and minimum lengths.

Measure the period of your pendulum when it is set to 4 or 5 different lengths. Make sure that you swing the pendulum through a small angle, no more than 15 degrees from the vertical. Make two measurements of the period at each length, to check for one-time errors.

Draw a graph which shows the period of the pendulum on the Y-axis, and the length of the pendulum on the X-axis. Plot all your data. Write the formula for period of a pendulum as a function of its length. Draw a curve on your graph which exhibits this expected, theoretical behavior. Does your pendulum exhibit this behavior? If it doesn't, explain why not.

Submit a report which contains the pictures and descriptions of your experiment, as well as the results. You may also include interesting items you discovered during the course of the procedure.

This page maintained by Michael Richmond. Last modified Jan 31, 2012.