Newton s Cradle is a classic desk toy. Also known as "Balance Balls", "Newton s Pendulum", "Kinetic Balls" and "Newton s Balls", this executive office toy demonstrates the law of conservation of momentum.
The clacking of the balls will keep you entertained throughout the day. Pull back one or more of the balls, release them and the same number of balls will swing up on the opposite side. The balls will click back and forth until they stop.