Atom used carbon dating
Next comes the question of how scientists use this knowledge to date things.
Half the original quantity of carbon-14 will decay back to the stable element nitrogen-14 after only 5,730 years.
Knowing the number of atoms that decayed in our sample over a month, we can calculate the radiocarbon decay rate.
The standard way of expressing the decay rate is called the half-life.5 It’s defined as the time it takes half a given quantity of a radioactive element to decay.
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.
If we know what fraction of the carbon atoms are radioactive, we can also calculate how many radiocarbon atoms are in the lump.Through photosynthesis carbon dioxide enters plants and algae, bringing radiocarbon into the food chain.