Newton’s Cradle
Also known as Newton’s balls, the cradle is a device that demonstrated conservation of momentum and energy via a series of swinging, typically metal, spheres. Named after Sir Isaac Newton, the cradle usually consists of a series of identically sized metal balls suspended via a metal frame so that they are just touching while at rest.
The movement of the balls is restricted to the same plane, thus when one is lifted and released, the resulting force travels through the line of balls and pushes the last one upward - ensuring that the energy and momentum are both conserved.
