Atom used in radiocarbon dating
Using Carbon dating, we can determine with accuracy how old something is.
Carbon 14 is used, mainly by archaeologists, to date bones and other formerly living matter but not normally fossils.
3.5 decays/gram/minute of carbon would be produced by a sample 11,460 years old.
However, atmospheric testing of nuclear weapons in the late 1950's and early 1960's greatly increased the amount of radiocarbon in the atmosphere, so the decay rate of 14 decays per minute more than doubled.
Carbon dating uses the carbon-14 isotope, with a half life of about 5700 years.
The best samples are tree rings, but annually laminated sediments have also produced excellent results. Chudy, Eristavi, Pagva, Povinec, Sivo, and Togonidze. Anthropogenic 14C variations in atmospheric CO2 and wines.
The surplus "bomb" radiocarbon is just one of the effects human have had on the ratio of C.
During the industrial revolution (1850 - present) increasing amounts of fossil fuels were combusted.
Radiocarbon dating is used to determine the age of previously living organisms. The half lives of carbon isotopes are derived by studying their radioactive decay.
For carbon dating, the isotope used is Carbon-14, which has a half life of 5,700 years. If so, the official definition is "the determination of the age or date of organic matter from the relative proportions of the carbon isotopes carbon-12 and carbon-14 that it contains".