Experimenting With Pendulums

Galileo used pendulums extensively in his experiments. Early in his career, he researched the characteristics of their motion. Your team is to duplicate some of this research.

The First step is to build your own pendulum. A pendulum consists of three things:

• a length
• a weight to hang at the end of the length
• an anchor point

Feel free to make any kind of pendulum that you like. After constructing it, do the following steps, record your data and be prepared to bring your pendulum and your results to class on Monday May 5.

• Verify that pendulums almost always return to their initial point of release. Propose an explanation of this, especially an explanation that was consistent with the time of Galileo. Verify that this observation is independent of the mass and length of the pendulum.

• Verify, qualitatively, that your pendulum will come to rest eventually.

• Now you have to time how long it takes your pendulum to come to rest, but you can't use a clock. By whatever system you invent, verify that it takes longer for a heavier pendulum to come to rest than a lighter one. Speculate on a reason for this.

• Now construct a pendulum in which the weight of the bob is comparable to the weight of the length of string or rope or whatever your using. Explain why this doesn't work.

• Now you will have to do some more precise timing. Do it the way that galileo did and count hearbeats. Within that timing sequence, verify the following:
  The period of oscillation is independent of the weight of the bob
  The period of oscillation is independent of the amplitude of the oscilliation.
  The square of the period of the oscillation varies directly with the length of pendulum.

• Now demonstrate that your pendulum can be used as a reliable time measuring device for any kind of future experiment.