Spring energy is contained in materials and objects that can stretch when a force is placed on them and then later return to their original shape. A graphic of the most well known type of spring is shown below. The spring starts at an unstretched or equilibrium position (x=0). As the spring is stretched from this equilibrium position, spring energy is stored in the spring. The spring can be held until the spring is released and the spring energy is also released. Therefore, spring energy is a form of potential energy.

Many materials and objects can act like springs and contain spring energy that can look very different than the typical spring below. Some other examples of objects that act to store spring energy are: a trampoline, shock absorbers, a sling shot, a stretched rubber band, a bow pulled back with an arrow, the tennis strings in tennis or other racquet as the ball hits them, and spandex in your pants.