Radiation 25856 224837440 2008-07-10T17:14:55Z Husond 1732934 Reverted edits by [[Special:Contributions/91.106.188.147|91.106.188.147]] (using [[WP:HG|Huggle]]) {{otheruses}} '''Radiation''', as used in [[physics]], is [[energy]] in the form of [[waves]] or moving [[subatomic particles]] emitted by an atom or other body as it changes from a higher energy state to a lower energy state. Radiation can be classified as ''[[ionizing radiation|ionizing]]'' or ''[[non-ionizing radiation]]'', depending on its effect on atomic [[matter]]. The most common use of the word "radiation" refers to ionizing radiation. Ionizing radiation has enough energy to ionize atoms or molecules while non-ionizing radiation does not. ''[[Radioactive material]]'' is a physical material that emits ionizing radiation. [[Image:RadiationPenetration2-pn.png|300px|thumb|right|This shows three different types of radiation and their penetration levels]] ==Types of Radiation== There are three principal types of ionizing radiation: [[Alpha decay|alpha]], [[Beta decay|beta]] and [[Gamma ray|gamma]] radiation. They are all emitted from the nucleus of an unstable atom. Less commonly encountered are spontaneous [[nuclear fission]]; [[positron emission]], which is utilized in [[positron emission tomography]]; and [[neutron emission]]. [[Electron capture]] results in the spontaneous emission of an X-ray. Certain isotopes of [[radium]] have a decay mode where they emit an entire [[Carbon-12|<sup>12</sup>C<sub>6</sub>]] nucleus. ==Discovery== [[Wilhelm Röntgen]] is credited with the discovery of [[X-Rays]]. [[Henri Becquerel]] found that [[uranium]] salts caused fogging of an unexposed photographic plate, and [[Marie Curie]] discovered that only certain elements gave off these rays of energy. He named this behaviour [[radioactivity]]. In December of 1898, Marie Curie and [[Pierre Curie]] discovered radium in pitchblende. This new element was two million times more radioactive than uranium, as described by Marie. == See also == <div style="-moz-column-count:2; column-count:2;"> * [[Ionizing radiation]] * [[Non-ionizing radiation]] * [[Background radiation]], which actually refers to the background ionizing radiation * [[Black hole]] * [[Cosmic microwave background radiation]], 3[[kelvin|K]] [[blackbody radiation]] that fills the [[Universe]] * [[Radiant energy]], radiation by a source into the surrounding environment. * [[Radiation damage]] - adverse effects on materials and devices * [[Radiation hormesis]] - dosage threshold damage theory * [[Radiation poisoning]] - adverse effects on life forms * [[Radiation hardening]] - making devices resistant to failure in high radiation environments * [[Radioactive contamination]] * [[Radioactive decay]] * [[Hawking radiation]] * [[Cherenkov radiation]] * [[Cyclotron radiation]] * [[Solar radiation]] * [[Synchrotron radiation]] * [[Radiation reaction]] </div> [[Category:Radiation| ]] [[Category:Physics]] [[Category:Fundamental physics concepts]] {{nuclear-stub}} [[ar:إشعاع]] [[ca:Radiació]] [[cs:Záření]] [[da:Stråling]] [[de:Strahlung]] [[et:Kiirgus]] [[es:Radiación]] [[eo:Radiado]] [[fr:Rayonnement]] [[gl:Radiación]] [[is:Geislun]] [[it:Radiazione]] [[he:קרינה]] [[ms:Sinaran]] [[nl:Straling]] [[ja:放射]] [[no:Stråling]] [[nn:Stråling]] [[pl:Promieniowanie]] [[pt:Radiação]] [[ru:Излучение]] [[simple:Radiation]] [[sl:Sevanje]] [[sr:Зрачење]] [[fi:Säteily]] [[sv:Strålning]] [[tr:Işınım]] [[ur:اشعاع]] [[zh:放射線]]