When an object (lets say a 2 square ball or a basketball) has a certain amount of Elasticity and falls to the ground, it bounces up and doesn't go as high as it originally was, then falls again, bounces, doesn't go as high as the last time it was in the air, etc etc etc, all until it stops completely.

I don't know the math behind it and it would come in handy for my Physics engine. Does anyone know anything about Elasticity and the maths behind it?