The history of radiocarbon dating
The radioactive decay of carbon-14 follows an exponential decay.
A quantity is said to be subject to exponential decay if it decreases at a rate proportional to its value.
When these curves are used, their accuracy and shape are the factors that determine the accuracy and age obtained for a given sample.
Plants take up atmospheric carbon dioxide by photosynthesis, and are ingested by animals, so every living thing is constantly exchanging carbon-14 with its environment as long as it lives.
After plants die or they are consumed by other organisms (for example, by humans or other animals) the C allows the age of the sample to be estimated.
The technique of radiocarbon dating was developed by Willard Libby and his colleagues at the University of Chicago in 1949.
Symbolically, this can be expressed as the following differential equation, where are customarily given in years BP which implies t(BP) = -t because the time arrow for dates runs in reverse direction from the time arrow for the corresponding ages.
From these considerations and the above equation, it results: For a raw radiocarbon date: C calibration curve.
Carbon dioxide also permeates the oceans, dissolving in the water.
Emilio Segrè asserted in his autobiography that Enrico Fermi suggested the concept to Libby in a seminar at Chicago that year.
Libby estimated that the steady state radioactivity concentration of exchangeable carbon-14 would be about 14 disintegrations per minute (dpm) per gram.
A very small percentage of carbon, however, consists of the isotope carbon 14, or radiocarbon, which is unstable.
Carbon 14 has a half-life of 5,780 years, and is continuously created in Earth's atmosphere through the interaction of nitrogen and gamma rays from outer space.
Carbon-14 has a half-life of 5730 years, meaning that the amount of carbon-14 in a sample is halved over the course of 5730 years due to radioactive decay.