Examples of use include analyzing charcoal from prehistoric caves, ancient linen and wood, and mummified remains.
It is often used on valuable artwork to confirm authenticity.
By knowing how much carbon-14 is left in a sample, the age of the organism and when it died can be worked out.
Radiocarbon dating has been used extensively since its discovery.
This is why radiocarbon dating is only useful for dating objects up to around 50,000 years old (about 10 half-lives).
Radioactive carbon-14 is continually formed in the atmosphere by the bombardment of cosmic ray neutrons on nitrogen-14 atoms.
Once the organism dies, however, it ceases to absorb carbon-14, so that the amount of the radiocarbon in its tissues steadily decreases.
Carbon-14 has a half-life of 5,730 ± 40 years— during the succeeding 5,730 years.
For example, if you start off with 1000 radioactive nuclei with a half-life of 10 days, you would have 500 left after 10 days; you would have 250 left after 20 days (2 half-lives); and so on.
The half-life is always the same regardless of how many nuclei you have left, and this very useful property lies at the heart of radiocarbon dating. The graph below shows the decay curve (you may recognize it as an exponential decay) and it shows the amount, or percent, of carbon-14 remaining.
A child mummy is found high in the Andes and the archaeologist says the child lived more than 2,000 years ago.