Newton's Cradle is used to demonstrate the conservation of energy and momentum. Lift and drop one ball, and the last ball will do the opposite motion. Now lift and drop first two ball and the last two balls will do the opposite motion. It contains 6 steel balls and the diameter of each ball is 19 mm and they are hung by Nylon wires. The base is made from solid cast iron. It is also called Newtonian Demonstrator.