Question: what is radiation?

Samantha Watson answered on 8 Nov 2016:

Radiation is the emission of a type of energy. That can be an energy wave – in a similar way as light is a type of wave, there are waves that we might not see or hear but carry energy. Or it can be the emission of sub-atomic particles – really really tiny particles. If these waves or particles pass through material (including human tissues) they can interact with the atoms in the material. Some types of radiation can produce charged particles in the material – this is known as ionisation, and radiation that can do this is known as ionising radiation. Xrays, gamma rays, and alpha and beta particles are types of ionising radiation. Other types of radiation that can’t do this are known as non-ionising radiation and examples of this are normal visible light, ultraviolet light, radiowaves, lasers, and microwaves.