Because carbon is expected to be thoroughly mixed throughout the biosphere, atmosphere, and oceans, living organisms (which continually “take in” carbon throughout their lifetimes) are expected to have the same C in their bodies begins to decrease.

In principle, this decay rate may be used to “date” the time since an organism’s death.

The halflife of carbon 14 is 5730 ± 30 years, and the method of dating lies in trying to determine how much carbon 14 (the radioactive isotope of carbon) is present in the artifact and comparing it to levels currently present in the atmosphere.Above is a graph that illustrates the relationship between how much Carbon 14 is left in a sample and how old it is.Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material.Nearly anyone can verify this for themselves using basic multiplication and division.Radiocarbon Basics Carbon comes in three “varieties” or isotopes: C is 5,730 years.Carbon-12 is a stable isotope; that is, it doesn't decay naturally.Carbon-14 on the other hand is an unstable isotope; that is, it decays naturally over time. It is produced naturally in the atmosphere and mixes with carbon-12 becoming part of our planet's biosphere.