The conservation of energy
The capacity for doing work. cannot be created or destroyed, so it is always conserved. This means that energy is regularly transferred from one store to another, although sometimes it is considered to be 'wasted' when it is transferred to a store that is not useful.
Since energy is always conserved, all the energy in the universe was present at the The scientific theory that describes the early development of the Universe. and will still be around at the very end of time.
Learn more on conservation and dissipation of energy in this podcast
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Examples of conservation of energy
The skydiver
When a skydiver jumps out of a plane, the following energy transfers take place:
- the skydiver's The energy stored by an object lifted up against the force of gravity. Also known as GPE. decreases as their altitude decreases
- the skydiver's Energy which an object possesses by being in motion. store increases as their speed increases
- the thermal store of the air and the skydiver increases, as there is friction between the skydiver and the air particles
No energy is destroyed or created during this process. As the gravitational store of energy decreases, the thermal and kinetic stores increase.
Smartphones
All smartphones contain a battery that acts as a chemical energy store. When a smartphone is in use, the following energy transfers take place:
- the battery's chemical energy store is transferred by the flow of an electric current to light up the screen and to produce sound
- the light that comes from a smartphone is emitted as visible radiation
- sound waves are produced by a speaker that vibrates
- A type of stored energy. It is taken in when chemical bonds break, and given out when chemical bonds are made. from the battery is also transferred into thermal energy (which is why phones heat up in use)