data sheet (link goes to Google Docs) for them to fill in; they will need three of them to record data for the entire experiment.
This is one experiment in which the kids are very much surprised by the results. They expected that lifting the weight higher up would increase the time for 10 swings; they also expected a heavier weight to make a difference. Only the length of the string matters.
Related Gizmos: Period of a Pendulum and Pendulum Clock