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. Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός A wave is a disturbance that propagates through Space and Time, usually with transference of Energy. A subatomic particle is an elementary or composite Particle smaller than an Atom. Radiation can be classified as ionizing or non-ionizing radiation, depending on its effect on atomic matter. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation Non-ionizing radiation (or esp in British English, non-ionising radiation) refers to any type of Electromagnetic radiation that does not carry enough Matter is commonly defined as being anything that has mass and that takes up space. 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. A radionuclide is an Atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created

This shows three different types of radiation and their penetration levels

Types of Radiation

There are three principal types of ionizing radiation: alpha, beta and gamma radiation. Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions 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. Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may Positron emission is a type of Beta decay, sometimes referred to as " beta plus " (&beta+ Positron emission tomography ( PET) is a Nuclear medicine imaging technique which produces a three-dimensional image or map of functional processes in the Neutron emission is a type of Radioactive decay of atoms containing excess Neutrons in which a neutron is simply ejected from the nucleus Electron capture results in the spontaneous emission of an X-ray. Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the Certain isotopes of radium have a decay mode where they emit an entire ¹²C₆ nucleus. Radium (ˈreɪdiəm is a radioactive Chemical element which has the symbol Ra and Atomic number 88 Carbon-12 is the most abundant of the two stable Isotopes of the element Carbon, accounting for 98

Discovery

Wilhelm Roentgen is credited with the discovery of X-Rays. Wilhelm Conrad Röntgen (27 March 1845 &ndash 10 February 1923 was a German physicist, who on 8 November 1895 produced and detected Electromagnetic X-radiation (composed of X-rays) is a form of Electromagnetic radiation. 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. Antoine Henri Becquerel (15 December 1852 &ndash 25 August 1908 was a French Physicist, Nobel laureate, and one of the discoverers of Radioactivity Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the She named this behaviour radioactivity. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation.

In December of 1898, Marie Curie and Pierre Curie discovered radium in pitchblende. Pierre Curie (15 May 1859 &ndash 19 April 1906 was a French physicist, a pioneer in Crystallography, Magnetism, Piezoelectricity This new element was two million times more radioactive than uranium, as described by Marie.

See also