what is radiation

Radiation is energy that moves from one place to another in the form of waves or particles. It can come from unstable atoms that undergo radioactive decay, or it can be produced by machines. There are two basic physical forms of radiation: electromagnetic radiation and particle radiation. Electromagnetic radiation is pure energy with no weight, and it includes vibrating or pulsating rays or "waves" of electrical and magnetic energy. Particle radiation is tiny fast-moving particles that have both energy and mass. Radiation can be categorized as either ionizing or non-ionizing depending on how it affects matter. Ionizing radiation carries more than 10 eV, which is enough to ionize atoms and molecules and break chemical bonds. This is an important distinction due to the large difference in harmfulness to living organisms. Some sources of radiation include the sun, microwave ovens, and radioactive atoms.