.A spring is an example of an elastic material, or a material that can be compressed or stretched and is able to return to its original shape. Think of familiar objects that contain springs - what happens when you compress the spring? Well, this requires work on your part to compress the spring. What happens when you let the spring go? It snaps back! In other words, when you compress the spring, you are doing work and exerting a force on the spring and now the spring is storing a type of potential energy called 'elastic potential energy'. Springs do work on objects when they return to the equilibrium or zero position.

The equation for elastic potential energy is