Potential vs kinetic energy
The simplest way to classify energy is by dividing it into kinetic energy and potential energy. This distinction is, however, not enough to fully describe the different ways in which an object or a system can possess energy. Hence we have nine major forms of energy: sound, thermal, light (radiant), kinetic (motion), nuclear, gravitational, elastic, chemical and electromagnetic.
Kinetic energy is associated with motion. From an oxygen molecule through to a planet, the more mass an object has and the faster it moves, the greater its kinetic energy. The motion of different types of objects gives rise to different forms of kinetic energy.
Potential energy has its roots in the force acting between two objects and the distance between them. For example, the potential energy of a rock on top of a hill comes from the gravitational force between Earth and the rock. The more massive the rock, and the greater its height, the bigger its potential energy. Different forces give rise to potential energy under different names. To learn much more about energy, be sure to pick up issue 51 of How It Works available from WHSmith, Barnes & Noble, supermarkets and all good newsagents from today.