Newton's Cradle is a device that demonstrates the principles of momentum and energy conservation. It consists of a series of suspended metal balls, typically five, that are aligned in a straight line. When one ball is lifted and released, it strikes the next ball, transferring its energy and momentum through the series, resulting in the last ball swinging outward. The motion continues as the balls swing back and forth, illustrating how energy is conserved in a closed system. Newton's Cradle is often used in classrooms and offices as a visual representation of physics concepts, making it both educational and entertaining.