C 14 age dating
As you learned in the previous page, carbon dating uses the half-life of Carbon-14 to find the approximate age of certain objects that are 40,000 years old or younger.
In the following section we are going to go more in-depth about carbon dating in order to help you get a better understanding of how it works.
Forensic anthropologists at The University of Arizona took advantage of this fact in a recent study funded by NIJ.
The researchers wanted to find out if they could identify a person's year of birth or year of death using precise measurements of carbon-14 levels in different post-mortem tissues.
Adult teeth are formed at known intervals during childhood.
The researchers found that if they assumed tooth enamel radiocarbon content to be determined by the atmospheric level at the time the tooth was formed, then they could deduce the year of birth.
Radiocarbon dating is a method of estimating the age of organic material.
It was developed right after World War II by Willard F.
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.
When these energetic neutrons collide with a nitrogen-14 (seven protons, seven neutrons) atom it turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).
Since Nitrogen gas makes up about 78 percent of the Earth's air, by volume, a considerable amount of Carbon-14 is produced.
Before the nuclear age, the amount of radiocarbon in the environment varied little in the span of a century.
In contrast, from 1955 to 1963, atmospheric radiocarbon levels almost doubled.Traditional radiocarbon dating is applied to organic remains between 500 and 50,000 years old and exploits the fact that trace amounts of radioactive carbon are found in the natural environment.Now, new applications for the technique are emerging in forensics, thanks to research funded by NIJ and other organizations.Age determinations can also be obtained from carbonate deposits such as calcite, dissolved carbon dioxide, and carbonates in ocean, lake, and groundwater sources.