Carbon Dating - What Is It And How Does It Work?

This is how carbon dating works: Carbon is a naturally abundant element found in the atmosphere, in the earth, in the oceans, and in every living creature. C-12 is by far the most common isotope, while only about one in a trillion carbon atoms is C-14. C-14 is produced in the upper atmosphere when nitrogen-14 (N-14) is altered through the effects of cosmic radiation bombardment (a proton is displaced by a neutron effectively changing the nitrogen atom into a carbon isotope). The new isotope is called "radiocarbon" because it is radioactive, though it is not dangerous. It is naturally unstable and so it will spontaneously decay back into N-14 after a period of time. It takes about 5,730 years for half of a sample of radiocarbon to decay back into nitrogen. It takes another 5,730 for half of the remainder to decay, and then another 5,730 for half of what's left then to decay and so on. The period of time that it takes for half of a sample to decay is called a "half-life."

Carbon Dating - The Premise
Carbon dating is a dating technique predicated upon three things:

• The rate at which the unstable radioactive C-14 isotope decays into the stable non-radioactive N-14 isotope,
• The ratio of C-12 to C-14 found in a given specimen,
• And the ratio C-12 to C-14 found in the atmosphere at the time of the specimen's death.