When a rubber band is stretched, the bonds between the polymer chains in the rubber are stretched and broken. This requires energy, which is stored in the rubber band as potential energy. When the rubber band is released, the potential energy is converted into kinetic energy, causing the rubber band to snap back to its original shape.

The amount of potential energy stored in a stretched rubber band depends on the amount of force required to stretch it and the distance it is stretched. The greater the force and the greater the distance, the more potential energy is stored.