Chemical dating techniques
Thus dating that particular tree does not necessarily indicate when the fire burned or the structure was built.For this reason, many archaeologists prefer to use samples from short-lived plants for radiocarbon dating.Heating an item to 500 degrees Celsius or higher releases the trapped electrons, producing light.
One of the most widely used and well-known absolute dating techniques is carbon-14 (or radiocarbon) dating, which is used to date organic remains.
One of the most widely used is potassium–argon dating (K–Ar dating).
Potassium-40 is a radioactive isotope of potassium that decays into argon-40.
Carbon-14 moves up the food chain as animals eat plants and as predators eat other animals. It takes 5,730 years for half the carbon-14 to change to nitrogen; this is the half-life of carbon-14.
After another 5,730 years only one-quarter of the original carbon-14 will remain.Absolute dating provides a numerical age or range in contrast with relative dating which places events in order without any measure of the age between events.