Carbon 14 or radiocarbon dating
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.
Radiocarbon dating can be used on samples of bone, cloth, wood and plant fibers.
The half-life of a radioactive isotope describes the amount of time that it takes half of the isotope in a sample to decay.
Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material.
The stable form of carbon is carbon 12 and the radioactive isotope carbon 14 decays over time into nitrogen 14 and other particles.
After 5,730 years, the amount of carbon 14 left in the body is half of the original amount.
At any particular time all living organisms have approximately the same ratio of carbon 12 to carbon 14 in their tissues.
This is actually a mini-simulator, in that it processes a different sample each time and generates different dates.
Radiocarbon dating can easily establish that humans have been on the earth for over twenty thousand years, at least twice as long as creationists are willing to allow.
Where t is the age of the fossil (or the date of death) and ln() is the natural logarithm function.
If the fossil has 35% of its carbon 14 still, then we can substitute values into our equation.