Balls were used in ancient history by the early Egyptians and the ancient Greeks and Romans.
In modern times balls have been used in machinery. The ball bearing is a device used to reduce the friction of miving parts in a wide variety of machines. Ball bearings use hardened steel balls.
Popular games involving balls include:
BasebalL? FootbalL?, or SocceR AmericanFootball DodgebalL? TenniS GolF? BasketbalL?