Anthropologists can estimate the age of a bone or other organic matter by its carbon-14 content.

Anthropologists can estimate the age of a bone or other organic matter by its carbon-14 content. The carbon-14 in a living organism is constant until the organism dies, after which carbon-14 decays with first-order kinetics and a half-life of 5730 years. Suppose a bone from an ancient human contains 18.5% of the {rm C}-14 found in living organisms.