Superballs

There are a number of physical concepts, such as transfer between kinetic and potential energy and momentum conservation, that can be demonstrated using bouncy rubber balls. One of the most popular is the superball bounce, where two or more superballs are dropped from a height one on top of the other. The result after the collision with the floor is quite surprising. If two balls are dropped simultaneously, one on top of the other, so that the top ball is much lighter that the bottom, then on collision with the floor the top ball will shoot up to a height much greater than the original dropping distance. This will work well when the ratio of the balls' masses is about five or more. Theoretically, if the ratio of the masses is infinite, then the lighter ball should reach exactly nine times the height of release.

If the experiment is tried with three balls, then the top ball should theoretically reach a height 49 times the original release height. If seven balls are dropped from a height of 1km above the earth's surface, then the top ball attains a velocity greater than the escape velocity of the earth and will hit the moon!