What is Radiation?
In [[physics]], '''radiation''' is the emission or transmission of [[energy]] in the form of [[waves]] or [[particles]] through space or through a [[material]] medium.<ref>{{cite web |url=http://scienceworld.wolfram.com/physics/Radiation.html |title=Radiation |last=Weisstein |first=Eric W. |website=Eric Weisstein's World of Physics |publisher=Wolfram Research |accessdate=2014-01-11}}</ref><ref>{{cite web |url=http://www.thefreedictionary.com/radiation |title=Radiation |website=The free dictionary by Farlex |publisher=Farlex, Inc. |accessdate=2014-01-11}}</ref> This includes: # [[electromagnetic radiation]] such as [[radio waves]], [[visible light]], and [[x-ray]]s # [[particle physics|particle radiation]] such as [[alpha radiation|α]], [[beta particle|β]], and [[neutron]] radiation # [[acoustics|acoustic]] radiation such as [[ultrasound]], [[sound]] # [[seismology|seismic waves]]. Radiation may also refer to the energy, waves, or particles being radiated. Originally, radiation waves do not contain particles as they are transferred to [[Earth]] by the [[Sun]] for example. == Electromagnetic radiation == Many people are already familiar with [[electromagnetic radiation]] (EMR), including light. The [[electromagnetic spectrum]] shows the types of radiation according to their [[wavelength]] and [[frequency]]. Some kinds are: * '''Ionizing radiation''' comes from [[radioactive]] materials and [[X-ray]] machines and '''non-ionizing radiation''' comes from other sources. Ionizing radiation carries more than 10 [[eV]] (electronvolts), which is enough to ionize atoms and molecules, and break [[chemical bond]]s. This is important for its harmfulness to living organisms. Non-ionizing radiation does not cause microscopic damage, but it can make things hotter and some types can cause chemical changes. ** '''X-rays and gamma rays''': These very strong rays are commonly used in medicine to photograph the interior of the body and treat [[cancer]]. However, in large amounts, they are dangerous to life. ** '''Ultraviolet light