What is 14c dating
The carbon-14 isotope would vanish from Earth's atmosphere in less than a million years were it not for the constant influx of cosmic rays interacting with molecules of nitrogen (NFigure 1: Diagram of the formation of carbon-14 (forward), the decay of carbon-14 (reverse).
The precise dating of ancient charcoal found near a skull is helping reveal a unique period in prehistory.
Part of the result of these collisions is the production of radiocarbon (C, pronounced "c fourteen"), carbon atoms which are chemically the same as stable carbon, but have two extra neutrons.
Radiocarbon is not stable; over time radiocarbon atoms decay into nitrogen atoms.
(This, in turn, is caused by variations in the magnetic fields of the earth and sun, for example.) Although the ratio of radiocarbon to stable carbon in the atmosphere has varied over time, it is quite uniform around the globe at any given time because the atmosphere mixes very quickly and constantly.
Plants obtain all their carbon atoms from the atmosphere.
In earth and environmental sciences, radioactive isotopes, atom variants that decay over time, play a major role in age determination.