Radio carbon dating method
The C-14 method cannot be used on material more than about 50,000 years old because of this short half-life.Other isotopes are used by geologists to date older material.
One standard deviation has a 68% probability and two standard deviations have a 95% probability.
Radiocarbon dating has had an enormous impact on archaeology around the world since it made it possible to date carbon and wood could be directly without dependence on characteristic artifacts or written historical records.
Carbon is naturally in all living organisms and is replenished in the tissues by eating other organisms or by breathing air that contains carbon.
At any particular time all living organisms have approximately the same ratio of carbon 12 to carbon 14 in their tissues.
Radiocarbon dating is one of the best known archaeological dating techniques available to scientists, and the many people in the general public have at least heard of it.
But there are many misconceptions about how radiocarbon works and how reliable a technique it is.
C is created in the atmosphere by cosmic radiation and is taken up by plants and animals as long as they live.
Upon death, the isotope begins to decay and after 5730±40 years half of it is gone.
In the case of radiocarbon dating, the half-life of carbon 14 is 5,730 years.
This half life is a relatively small number, which means that carbon 14 dating is not particularly helpful for very recent deaths and deaths more than 50,000 years ago.
Each radiocarbon date has a statistical probability shown by the ± number.