However, at the moment of death, the amount of carbon-14 begins to decrease because it is unstable, while the amount of carbon-12 remains constant in the sample.Half of the carbon-14 degrades every 5,730 years as indicated by its half-life.

Radiation counters are used to detect the electrons given off by decaying C-14 as it turns into nitrogen.

The amount of C-14 is compared to the amount of C-12, the stable form of carbon, to determine how much radiocarbon has decayed, thereby dating the artifact.

The ratio of normal carbon (carbon-12) to carbon-14 in the air and in all living things at any given time is nearly constant.

Maybe one in a trillion carbon atoms are carbon-14.

When these energetic neutrons collide with a nitrogen-14 (seven protons, seven neutrons) atom it turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).

Since Nitrogen gas makes up about 78 percent of the Earth's air, by volume, a considerable amount of Carbon-14 is produced.

The word "estimates" is used because there is a significant amount of uncertainty in these measurements.

Each sample type has specific problems associated with its use for dating purposes, including contamination and special environmental effects.

It can be used on objects as old as about 62,000 years.

Follow the links below to learn more about radiocarbon dating. Radiocarbon dating uses carbon isotopes A special kind of radiocarbon dating: Bomb radiocarbon dating What is an isotope?

In order to date the artifact, the amount of Carbon-14 is compared to the amount of Carbon-12 (the stable form of carbon) to determine how much radiocarbon has decayed.