Radioactive carbon dating method
There are three carbon isotopes that occur as part of the Earth's natural processes; these are carbon-12, carbon-13 and carbon-14.The unstable nature of carbon 14 (with a precise half-life that makes it easy to measure) means it is ideal as an absolute dating method.
Because carbon-14 decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon.(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.date of organic material - but an approximate age, usually within a range of a few years either way.The other method is “Relative Dating” which gives an order of events without giving an exact age (1): typically artefact typology or the study of the sequence of the evolution of fossils.It also has some applications in geology; its importance in dating organic materials cannot be underestimated enough.
In 1979, Desmond Clark said of the method “we would still be foundering in a sea of imprecisions sometime bred of inspired guesswork but more often of imaginative speculation” (3).
The following article is primarily based on a discussion of radiocarbon dating found in The Biblical Chronologist Volume 5, Number 1. Radiocarbon dating is based on a few relatively simple principles. The vast majority of these are C (pronounced "c twelve"), the stable isotope of carbon.
However, cosmic radiation constantly collides with atoms in the upper atmosphere.
The other two isotopes in comparison are more common than carbon-14 in the atmosphere but increase with the burning of fossil fuels making them less reliable for study (2); carbon-14 also increases, but its relative rarity means its increase is negligible. After this point, other Absolute Dating methods may be used.
Today, the radiocarbon-14 dating method is used extensively in environmental sciences and in human sciences such as archaeology and anthropology.
Rachel Wood does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.