What can a rubber band and a cotton ball teach you about potential and kinetic energy?
Join Michael Lewandowski to make your own cotton-ball launcher and find out!
When you stretch a rubber band it stores elastic potential energy—the energy stored inside a material when it is stretched, squished, bent or twisted. This is different from gravitational potential energy, which is stored in an object that is lifted off the ground. Both types of potential energy can be converted to kinetic—the energy of motion. All moving objects have kinetic energy, but motionless ones have none. When energy is converted between forms the total amount of energy remains the same. In other words, it is conserved. (Some energy, however, may also be converted to heat due to friction—but that is still a form of energy.)