Radiocarbon dating half life
Calibration is not only done before an analysis but also on analytical results as in the case of radiocarbon dating—an analytical method that identifies the age of a material that once formed part of the biosphere by determining its carbon-14 content and tracing its age by its radioactive decay.
Carbon-14 is a naturally occurring isotope of the element carbon.
It is also called “radiocarbon” because it is unstable and radioactive relative to carbon-12 and carbon-13.
Carbon consists of 99% carbon-12, 1% carbon-13, and about one part per million carbon-14.
Radiocarbon dating uses the amount of Carbon 14 (C14) available in living creatures as a measuring stick.
All living things maintain a content of carbon 14 in equilibrium with that available in the atmosphere, right up to the moment of death.
Results of carbon-14 dating are reported in radiocarbon years, and calibration is needed to convert radiocarbon years into calendar years.
These dates become farther off the older the time is indicated.
When an organism dies, the amount of C14 available within it begins to decay at a half life rate of 5730 years; i.e., it takes 5730 years for 1/2 of the C14 available in the organism to decay.
Comparing the amount of C14 in a dead organism to available levels in the atmosphere, produces an estimate of when that organism died.