Posted: 3 November 2000

The capacity to do work. Energy takes a variety of forms and can be converted from one form to another to meet specific needs. There is no simple universally accepted classification of energy forms, but most classifications include:

  • kinetic - the energy possessed by an object in motion
  • potential - the energy possessed by an object as a result of its position. A bag of flour on a shelf, for example, retains the energy expended to place it in that position. If the bag falls off the shelf the potential energy will become kinetic energy.
  • thermal - heat energy
  • electrical - the energy associated with an electric charge in an electric field
  • chemical - the energy released during a chemical reaction
  • nuclear - the energy released during nuclear reaction
  • radiant - energy transmitted in the form of radiation
Energy can be converted from one form to another. The chemical energy in coal, for example, is converted into thermal energy through combustion, which in turn can be converted into electrical energy in a thermal electric power station.