The carbon-14 method was developed by the American physicist Willard F. Libby about 1946. It has proved to be a versatile technique of dating fossils and archaeological specimens from 500 to 50,000 years old.

## How old is a sample of carbon-14 if only 12.5% remains?

The half-life for 14C is approximately 5700 years, therefore the 14C isotope is only useful for dating fossils up to about 50,000 years old. Fossils older than 50,000 years may have an undetectable amount of 14C.

## How old is a sample of carbon-14 that has undergone 2 half lives?

5,730 years Carbon-14 has a relatively short half-life of 5,730 years, meaning that the fraction of carbon-14 in a sample is halved over the course of 5,730 years due to radioactive decay to nitrogen-14.