Radiation is the term used for all phenomena characterised by the transport of energy, either by waves or sub-atomic particles. The highest energy waves can behave just like particles, and sub-atomic particles can behave just like waves. This is called the wave – particle duality.

For more information on different aspects of radiation click on the right-hand links to:

• the electomagnetic spectrum
• particle radiation: radioactivity and cosmic rays
• the effects of magnetic fields
• radiation and life