The Foucault pendulum: a simple explanation, Mechanics with animations and video film clips.

Play with one or two pendulums and discover how the period of a simple pendulum depends on the length of the string, the mass of the pendulum bob, the strength of gravity, and the amplitude of the swing.

Measure the period using the stopwatch or period timer.
Physclips provides multimedia education in introductory physics (mechanics) at different levels. Modules may be used by teachers, while students may use the whole package for self instruction or for reference. Observe the energy in the system in real-time, and vary the amount of friction.