Carbon dating half life period
As long as an organism is alive, the amount of C-14 in its cellular structure remains constant.
But when the organism dies, the amount of C-14 begins to decrease.
Carbon-14 (C-14), a radioactive isotope of carbon, is produced in the upper atmosphere by cosmic radiation.
The primary carbon-containing compound in the atmosphere is carbon dioxide, and a very small amount of carbon dioxide contains C-14.
It might take a millisecond, or it might take a century. But if you have a large enough sample, a pattern begins to emerge.
It takes a certain amount of time for half the atoms in a sample to decay.
Half-lives for various radioisotopes can range from a few microseconds to billions of years.
See the table below for a list of radioisotopes and each of unique their half-lives. After 86 minutes, half of the atoms in the sample would have decayed into another element, Lanthanum-139.
After another 86 minutes, half of the 5 grams of Barium-139 would decay into Lanthanum-139; you would now have 2.5 grams of Barium-139 and 7.5 grams of Lanthanum-139.Plants absorb C-14 during photosynthesis, so C-14 is incorporated into the cellular structure of plants.