Radiocarbon dating is essentially a method designed to measure residual radioactivity.
is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past.
It can be used on objects as old as about 62,000 years.
Radiocarbon, or carbon 14, is an isotope of the element carbon that is unstable and weakly radioactive. Carbon 14 is continually being formed in the upper atmosphere by the effect of cosmic ray neutrons on nitrogen 14 atoms.
It is rapidly oxidized in air to form carbon dioxide and enters the global carbon cycle.
Image via The Cosmic Story of Carbon-14 by Ethan Siegel, via Simon Swordy (U.
Chicago), via NASA of those two isotopes in a sample.
Plants and animals assimilate carbon 14 from carbon dioxide throughout their lifetimes.
When they die, they stop exchanging carbon with the biosphere and their carbon 14 content then starts to decrease at a rate determined by the law of radioactive decay.
Follow the links below to learn more about radiocarbon dating. Radiocarbon dating uses carbon isotopes A special kind of radiocarbon dating: Bomb radiocarbon dating Although an element’s number of protons cannot change, the number of neutrons can vary slightly from each atom.
Atoms of the same element that have different numbers of neutrons are called isotopes.
In The Cosmic Story of Carbon-14 Ethan Siegel writes: The only major fluctuation [in carbon-14] we know of occurred when we began detonating nuclear weapons in the open air, back in the mid-20th Century.