What is radiation?
Australian Nuclear Science and Technology Organisation
Radiation can be described as energy or particles from a source that travel through space or other mediums. Light, heat, microwaves and wireless communications are all forms of radiation. The kind of radiation discussed here is called ionising radiation because it can produce charged particles (ions) in matter. Ionising radiation is emitted by a large range of natural materials, can be produced by everyday devices such as X-ray machines, and can also be emitted by unstable atoms. Atoms become unstable when they have the wrong amount of mass required to keep them stable, an excess of energy, or both. Unstable atoms are said to be radioactive. In order to reach stability these atoms give off, or emit, energy and/or mass. The energy is emitted in the form of electromagnetic radiation (i.e. light) and the mass is in the form of tiny particles. These emissions are called nuclear radiation and such atoms are said to be radioactive. Gamma radiation is an example of electromagnetic radiation. Beta and alpha radiation are examples of emitted particles. Ionising radiation can also be produced by devices such as X-ray machines.
Particles, Energy, Space, Ionizing radiations, Ionization, Gamma radiation
Australian Nuclear Science and Technology Organisation. (2013). What is radiation? Lucas Heights, NSW: Australian Nuclear Science and Technology Organisation.