And that gives the age (how long ago the organism died).
Climate records from a Japanese lake are set to improve the accuracy of the dating technique, which could help to shed light on archaeological mysteries such as why Neanderthals became extinct.
The rate of decay of carbon-14 is known so this can be used to estimate the age of the organism. When something dies its body stops taking in carbon.
Radiocarbon dating, or Carbon 14 dating, relies on processes of radioactive decay. From this point onwards the carbon in the body will begin to decay.
Ninety-nine percent of these also contain six neutrons.
The 6 proton 6 neutron atoms are said to have a mass of 12 and are referred to as "carbon-12." The nuclei of the remaining one percent of carbon atoms contain not six but either seven or eight neutrons in addition to the standard six protons.
Carbon-14 is continually produced in the upper atmosphere and then diffuses throughout it, reaching an equilibrium concentration.
As long as an organism it alive, it takes in carbon-14 from the atmosphere either directly (plants, for example) or indirectly (herbivores, and the carnivores that eat them).
When isotopes are to be designated specifically, the chemical symbol is expanded to identify the mass (for example, C is not stable.They measure what percentage of carbon has decayed into simpler elements.Then since they know the half-life of carbon (or the time it takes for 50% of an amount of carbon to decay into simpler elements) they can give an approx. Carbon has 3 isotopes: carbon-12, carbon-13, and carbon-14.The first two are stable, but carbon-14 is unstable and decays with a half-life of about 5,730 years.