5 uses of carbon dating
For determining age of fossils older than 60,000 years one uses a potassium-argon dating technique.
Potassium dating has a half life of 1.3 billion years, thus allowing the age of rocks several billions years old to be determined.
Radiocarbon activity of materials in the background is also determined to remove its contribution from results obtained during a sample analysis.
Background radiocarbon activity is measured, and the values obtained are deducted from the sample’s radiocarbon dating results.
When they die, they stop exchanging carbon with the biosphere and their carbon 14 content then starts to decrease at a rate determined by the law of radioactive decay.
It must be noted though that radiocarbon dating results indicate when the organism was alive but not when a material from that organism was used.
There are three principal techniques used to measure carbon 14 content of any given sample— gas proportional counting, liquid scintillation counting, and accelerator mass spectrometry.
Radiocarbon, or carbon 14, is an isotope of the element carbon that is unstable and weakly radioactive. Carbon 14 is continually being formed in the upper atmosphere by the effect of cosmic ray neutrons on nitrogen 14 atoms.
It is rapidly oxidized in air to form carbon dioxide and enters the global carbon cycle.