What is measured in the radiocarbon dating of organic materials?

the increase of carbon-12 in a living organism

the decrease in carbon-12 in a decaying organism

the ratio of carbon-14 to carbon-12 in a sample

the ratio of carbon-12 to carbon-14 in a sample

1 answer

In radiocarbon dating, the measurement focuses on the ratio of carbon-14 to carbon-12 in a sample. As living organisms take in carbon from their environment, they incorporate both carbon-12 and carbon-14. When they die, they stop taking in carbon-14, which begins to decay at a known rate (its half-life is about 5,730 years). By measuring the remaining amount of carbon-14 in a sample and comparing it to the stable carbon-12, scientists can estimate the age of the organic material.