Some of these carbon dioxide molecules the plant absorbs into its body are molecules formed from radioactive carbon-14.
In this way, every living thing on Earth absorbs an equal level of carbon-14 into its body.
When that plant or an animal dies, it is of course no longer able to feed and absorb any more carbon-14.
Since carbon-14 is a radioactive substance, it has a half-life, and gradually begins losing electron.
Carbon-14 is one form of radiometric test, but one very important feature distinguishes it from the others.
Other radiometric tests can be used only in determining the ages of volcanic rocks.
Carbon-14 dating, however, can be used to determine the ages of once-living things.That is because Carbon-14 is the only radioactive substance found in the bodies of living organisms.The Earth is constantly being bombarded by cosmic rays from outer space.These rays strike nitrogen-14, found in high levels in the atmosphere, and transform this into carbon-14, a radioactive substance.Radioactive carbon-14, a newly produced element, combines with oxygen in the atmosphere, forming another radioactive compound, C-14 O2.As we know, plants use CO2 (carbon dioxide), H2O (water) and solar rays in order to produce their nutrients.