Newtons Cradle

Energy is all around us and makes most things move around us. When you drop one ball towards another, the energy passes through the three balls until the very last ball. It then moves away but returns back down again. The balls show how energy move without disappearing. Slowly it will lose speed and finally stop.This happens because of air resistance and friction (a force that slows down the movement of the balls). But still the energy does not disappear, instead it goes out into the air and around the balls. The amount of energy in the universe is constant, that is, the same all the time.