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'''Radioactivity''' is the emission of high [[energy]] [[particles]] through the natural phenomenon of the decay of unstable [[isotopes]] of [[chemical elements]] into more stable forms, which are called ''daughter products.'' This type of emission is generally called nuclear radiation.

'''Radioactivity''' is the emission of high [[energy]] [[particles]] through the natural phenomenon of the decay of unstable [[isotopes]] of [[chemical elements]] into more stable forms, which are called ''daughter products.'' This type of emission is generally called nuclear radiation.

The most common types of nuclear radiation are alpha and beta radiation, and the processes for each are respectively alpha decay and beta decay.<ref>http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html</ref> There can also be gamma radiation associated with a nuclear decay. Alpha particles are [[helium]] nuclii (two protons and two neutrons); beta particles are high-energy [[electron]]s; gamma rays are high-energy [[photon]]s.  Alpha particles can normally be stopped by a sheet of paper, and beta particles can normally be stopped by healthy human skin, but gamma rays can penetrate one's body to cause great harm. Gamma radiation is also a form of electro-magnetic radiation, like X-rays or visible light.

The most common types of nuclear radiation are alpha and beta radiation, and the processes for each are respectively alpha decay and beta decay.<ref>http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html</ref> There can also be gamma radiation associated with a nuclear decay. Alpha particles are [[helium]] nuclei (two protons and two neutrons); beta particles are high-energy [[electron]]s; gamma rays are high-energy [[photon]]s.  Alpha particles can normally be stopped by a sheet of paper or healthy human skin. Beta particles and gamma rays can penetrate one's body to cause great harm. Gamma radiation is also a form of electro-magnetic radiation, like X-rays or visible light. (Contemporary jargon refers to alpha and beta ''particles'' and gamma ''rays'', though quantum mechanics makes the two actually the same.)

All forms of nuclear decay follow the fundamental rules of mass and energy balance.

All forms of radioactivity follow the fundamental rules of mass and energy balance.

==Alpha Decay==

==Alpha Decay==

:To my mind radio-activity is a real disease of matter. Moreover, it is a contagious disease. It spreads. You bring those debased and crumbling atoms near others and those too presently catch the trick of swinging themselves out of coherent existence. It is in matter exactly what the decay of our old culture is in society, a loss of traditions and distinctions and assured reactions. ...I am haunted by a grotesque fancy of the ultimate eating away and dry-rotting and dispersal of all our world. So that while man still struggles and dreams his very substance will change and crumble from beneath him. I mention this here as a queer persistent fancy. Suppose, indeed, that is to be the end of our planet; no splendid climax and finale, no towering accumulation of achievements, but just—atomic decay!<ref>Wells, H. G. (1909) [http://www.gutenberg.org/files/718/718-h/718-h.htm Tono-Bungay], online Project Gutenberg text; search for text string "real disease"</ref>

:To my mind radio-activity is a real disease of matter. Moreover, it is a contagious disease. It spreads. You bring those debased and crumbling atoms near others and those too presently catch the trick of swinging themselves out of coherent existence. It is in matter exactly what the decay of our old culture is in society, a loss of traditions and distinctions and assured reactions. ...I am haunted by a grotesque fancy of the ultimate eating away and dry-rotting and dispersal of all our world. So that while man still struggles and dreams his very substance will change and crumble from beneath him. I mention this here as a queer persistent fancy. Suppose, indeed, that is to be the end of our planet; no splendid climax and finale, no towering accumulation of achievements, but just—atomic decay!<ref>Wells, H. G. (1909) [http://www.gutenberg.org/files/718/718-h/718-h.htm Tono-Bungay], online Project Gutenberg text; search for text string "real disease"</ref>

==See Also==

=Notes and references==

 

==References==

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[[Category:Radioactivity]]

[[Category:Radioactivity]]