Energy transfers

Systems and stores

Energy can remain in the same store for millions of years or sometimes just for a fraction of a second. There are energy transfers going on all the time - whenever a system changes there is a change in the way some or all of the energy is stored.

Boat suspended from column, swings in circular arc. Highest point: no kinetic energy,  max gravitational potential energy. Lowest point: max kinetic energy, minimum gravitational potential energy.

A swinging pirate ship ride at a theme park

Kinetic energy is transferred into gravitational potential energy

Transferring energy

In each of these examples, energy is transferred by one of the following four types of energy transfer:

  • mechanical work - a force moving an object through a distance
  • electrical work - charges moving due to a potential difference
  • heating - due to temperature difference caused electrically or by chemical reaction
  • radiation - energy transferred as a wave, eg light and infrared - the Sun emits light radiation and infrared radiation

Doing 'work' is the scientific way of saying that energy has been transferred. For example, a grazing cow, a firing catapult and a boiling kettle are all doing 'work', as energy is being transferred.