It is not uncommon for a cosmic ray to collide with an atom in the atmosphere, creating a secondary cosmic ray in the form of an energetic neutron, and for these energetic neutrons to collide with nitrogen atoms.When the neutron collides, a nitrogen-14 (seven protons, seven neutrons) atom turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).Similarly, we could determine how long we would have to wait in order for there to be only 75 grams of uranium-238 left in the rock.
Plants and animals assimilate carbon 14 from carbon dioxide throughout their lifetimes.
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.
One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites.
Carbon dating, also known as radiocarbon dating, is a method of estimating the age of carbon-bearing materials up to 60,000 years old.
The amount of carbon-14 gradually decreases through radioactive beta decay with a half-life of 5,730 years.