Linné on line Physics and the Cosmos Physics and the Cosmos The atomic nucleus Use of Carbon-14 for dating

## Use of Carbon-14 for dating

At the Tandem-accelerator laboratory at Uppsala University one uses carbon-14 to determine the age of different organic materials. This is done by measuring the amount of carbon-14 in a material compared to the amount of carbon-12. Carbon-14 has a half-life of 5700 years. This means that the amount of carbon-14 is halved in this time. Carbon-12 on the other hand is stable. In living matter the carbon atoms are renewed all the time which means that the ratio of carbon-14 to carbon-12 atoms is constant. But in dead matter there is no renewal of carbon atoms which means that the amount of carbon-14 compared to carbon-12 decreases as the carbon-14 atoms decay. By measuring the relative amount of carbon-14 it is therefore possible to determine the age of the material.