Newtons cradle: Newtons cradle demonstrates the third law of motion by swinging the sphere; when a ball is lifted and released, it transmits power through the rest of the ball, pushing the end ball in the opposite direction Product material: Including steel ball, frosted glass, fishing line, plastic base The luminous Newton ball swings more dazzlingly at night. There is a luminous plate on the base, which is projected on the glass beads. The glass beads are colorful and very attractive Not only demonstrates the pendulum, but also demonstrates the law of conservation of momentum and energy. These swinging kinetic energy balls are you The perfect complement to desk decoration accessories or school teaching tools More durable and not rusty: more durable, easier to transfer and store more energy in collision Great for home ornament, study or office desk table decor accessories, etc. Also good for birthday gift and kids toy