Radioactive decay dating
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.
Radiocarbon dating is essentially a method designed to measure residual radioactivity.
In this method, the carbon 14 content is directly measured relative to the carbon 12 and carbon 13 present. Some inorganic matter, like a shell’s aragonite component, can also be dated as long as the mineral’s formation involved assimilation of carbon 14 in equilibrium with the atmosphere.
An age could be estimated by measuring the amount of carbon-14 present in the sample and comparing this against an internationally used reference standard.
The impact of the radiocarbon dating technique on modern man has made it one of the most significant discoveries of the 20th century.
Standard errors are also reported in a radiocarbon dating result, hence the “±” values.
These values have been derived through statistical means.