The definition of radiation is energy traveling through space, according to the World Nuclear Association. Radiation is classified as non-ionizing or ionizing, depending on whether it has enough energy to produce charged particles in matter.
The energy produced by microwaves, lights and radio waves is classified as non-ionizing radiation. This type of radiation has enough energy to cause movement or vibration, but it does not have enough energy to remove electrons from matter.
Ionizing radiation produces ions, which are charged particles, by removing electrons from atoms. This type of radiation is used to treat cancer and produce electricity. People who work with ionizing radiation must monitor their exposure because this type of radiation can damage matter. X-ray machines and tanning booths use ionizing radiation.