Why is carbon 14 useful in radioactive dating
All the people whose tissues were tested for the study were residents of the United States.Atmospheric dispersion tends to create uniform levels of carbon-14 around the globe, and researchers believe that these would be reflected in human tissues regardless of location.To determine year of birth, the researchers focused on tooth enamel.
Carbon-13 has 6 protons, just like other carbon isotopes, but it has 7 neutrons. Although 15 isotopes of carbon are known, the natural form of the element consists of a mixture of only three of them: carbon-12, carbon-13, and carbon-14. Measuring the difference in the radio between carbon-12 and carbon-14 is useful for dating the age of organic matter since a living organism is exchanging carbon and maintaining a certain ratio of isotopes.Radiocarbon levels in teeth formed before then contained less radiocarbon than expected, so when applied to teeth formed during that period, the method was less precise.To determine year of death, the researchers used radiocarbon levels in soft tissues.However, the researchers suggested that soft tissue radiocarbon content would be transferred to, and preserved in, the pupal cases of insects whose larvae feed on these tissues.Such insects are simply another link in the food chain.
Over the past six decades, the amount of radiocarbon in people or their remains depends heavily on when they were born or, more precisely, when their tissues were formed.