For Kinetic and Potential Energy is stored energy. Examples of potential energy are oil sitting in a barrel, or water in a lake in the mountains. When it is on its way up, it is using kinetic energy since the enrgy is in motion. When it reaches the top it has potential or stored energy.
This demenstrates potential energy because when the rubber band is tightly wound it has a lot of energy, but until you let go, the energy is stored up waiting to be unleashed. Theemenstrates kinetic energy because once you relese the top of the carousal, the rubber bands unwind quikly: this moivement is kinetic energy.