A mathematical explanation of carbon dating and half life dating sites for separated
The method developed in the 1940's and was a ground-breaking piece of research that would change dating methods forever. Libby calculated the rate of radioactive decay of the C isotope (4) in carbon black powder.
As a test, the team took samples of acacia wood from two Egyptian Pharaohs and dated them; the results came back to within what was then a reasonable range: 2800BC /- 250 years whereas the earlier independent dates (largely the dendrochronology records) were 2625 /- 75 years (3), (5).
Archaeologists had used Relative Dating methods to calculate their reigns.
Though their initial calculations were slightly incorrect thanks to the contaminants of extensive nuclear testing of the age, scientists soon discovered the error and developed methods that were more accurate, including a date of calibration to 1950.
The other two isotopes in comparison are more common than carbon-14 in the atmosphere but increase with the burning of fossil fuels making them less reliable for study (2); carbon-14 also increases, but its relative rarity means its increase is negligible. After this point, other Absolute Dating methods may be used.
Today, the radiocarbon-14 dating method is used extensively in environmental sciences and in human sciences such as archaeology and anthropology.
When an organism dies, it stops absorbing the radioactive isotope and immediately starts decaying (7).
As previously mentioned, the half life of the C isotope is 5,730 years - this means that it takes 5,730 years to reach half the radioactivity that the organism had at the point of death, another 5,730 years to reach 25% radioactivity it had at the point of death and so on.
The overlapping nature of the tree records means this is the most accurate record we have.This new method was based on gas and liquid scintillation counting and these methods are still used today, having been demonstrated as more accurate than Libby's original method (3).Willard Libby would receive a Nobel Prize for Chemistry in 1960.Radiocarbon dating is simply a measure of the level of C isotopes in the atmosphere can vary.This is why calibration against objects whose age is known is required (14).