Radiocarbon dating rests heavily on this assumption such that other sources of carbon 14 had, at first, not been considered nor accounted for.Nowadays, radiocarbon scientists had to perform calibration not only to convert their radiocarbon year results into calendar year but also to take into account the various factors that have major effects on the global levels of carbon 14, one of which is nuclear weapons testing.This means that things like stone, metal and pottery cannot usually be directly dated by this means unless there is some organic material embedded or left as a residue.As explained below, the radiocarbon date tells us when the organism was alive (not when the material was used).The amount of carbon-14 in the air has stayed the same for thousands of years.There is a small amount of radioactive carbon-14 in all living organisms because it enters the food chain.
Radiocarbon dating is a commonly used technique which relies on the fact that, although 99% of carbon atoms have six protons and six neutrons (carbon-12), about 1% have an extra neutron (carbon-13) and about one atom in a trillion has two extra neutrons (carbon-14).
There are two human activities recognized to have irreparably changed the global radiocarbon levels—the burning of fossil fuel and nuclear weapons testing.
Radiocarbon dating is one of the most widely used scientific dating methods in archaeology and environmental science.
The approximate time since the organism died can be worked out by measuring the amount of carbon-14 left in its remains compared to the amount in living organisms.
The radiocarbon dating method is based on certain assumptions on the global concentration of carbon 14 at any given time.