Foucault's Pendulum

The Foucault's Pendulum is a simple pendulum apparatus with a sand bath at the bottom. When you set the pendulum in motion, it goes about marking lines and curves on the sand. 

This simple device, with its black stand, is just the right size to sit on your desk. Its rhythmic movement allows beautiful patterns to be inscribed in the sand, while the pendulum tracks for over five minutes.