Living things contain carbon-14 and carbon-12 in a ratio that is the same as in the atmosphere at the time.When the organism dies, the ratio of carbon-14 to carbon-12 decreases, as carbon-14 decays and is no longer incorporated into the organism.

Carbon-14 is constantly be generated in the atmosphere and cycled through the carbon and nitrogen cycles.

Once an organism is decoupled from these cycles (i.e., death), then the carbon-14 decays until essentially gone.

He demonstrated the accuracy of radiocarbon dating by accurately estimating the age of wood from a series of samples for which the age was known, including an ancient Egyptian royal barge dating from 1850 BCE.

Before Radiocarbon dating was able to be discovered, someone had to find the existence of the C isotope.

Radiocarbon dating can date samples up to 50,000 years old.

Samples older than that contain so little carbon-14 that the dating process is inaccurate.

The technique of radiocarbon dating was developed by Willard Libby and his colleagues at the University of Chicago in 1949.

Emilio Segrè asserted in his autobiography that Enrico Fermi suggested the concept to Libby at a seminar in Chicago that year.

The equation relating rate constant to half-life for first order kinetics is $k = \dfrac \label$ so the rate constant is then $k = \dfrac = 1.21 \times 10^ \text^ \label$ and Equation $$\ref$$ can be rewritten as $N_t= N_o e^ \label$ or $t = \left(\dfrac \right) t_ = 8267 \ln \dfrac = 19035 \log_ \dfrac \;\;\; (\text) \label$ The sample is assumed to have originally had the same (rate of decay) of d/min.g (where d = disintegration).

In contrast, living material exhibit an activity of 14 d/min.g.

Above-ground nuclear weapons testing in the 1950s and 1960s resulted in a dramatic increase of carbon-14 in the atmosphere. Nuclear tests released lots of neutrons into the atmosphere.

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