Many people assume that rocks are dated at “millions of years” based on radiocarbon (carbon-14) dating. The most well-known of all the radiometric dating methods is radiocarbon dating.

Carbon-14 can yield dates of only “thousands of years” before it all breaks down.

It’s assumed to be the same number of carbon-14 atoms as in elephants living today.

carbon dating decay rate-4

If carbon-14 has formed at a constant rate for a very long time and continually mixed into the biosphere, then the level of carbon-14 in the atmosphere should remain constant.

If the level is constant, living plants and animals should also maintain a constant carbon-14 level in them.

Since each beta particle represents one decayed carbon-14 atom, we know how many carbon-14 atoms decay during a month.

Chemists have already determined how many atoms are in a given mass of each element, such as carbon.4 So if we weigh a lump of carbon, we can calculate how many carbon atoms are in it.

These rapidly combine with oxygen atoms (the second most abundant element in the atmosphere, at 21%) to form carbon dioxide (CO).

This carbon dioxide, now radioactive with carbon-14, is otherwise chemically indistinguishable from the normal carbon dioxide in the atmosphere, which is slightly lighter because it contains normal carbon-12.When animals eat the plants, the carbon-14 enters their bodies.The carbon-14 in their bodies breaks down to nitrogen-14 and escapes at the same rate as new carbon-14 is added. CARBON-14 IS DEPLETED (Figure 1c): When an animal dies the carbon-14 continues to break down to nitrogen-14 and escapes, while no new carbon-14 is added.Radiocarbon then enters animals as they consume the plants (Figure 1b).So even we humans are radioactive because of trace amounts of radiocarbon in our bodies.By comparing the surviving amount of carbon-14 to the original amount, scientists can calculate how long ago the animal died.