For example, uranium-lead dating can be used to find the age of a uranium-containing mineral.

It works because we know the fixed radioactive decay rates of uranium-238, which decays to lead-206, and for uranium-235, which decays to lead-207.

Plants absorb C-14 during photosynthesis, so C-14 is incorporated into the cellular structure of plants.

Plants are then eaten by animals, making C-14 a part of the cellular structure of all living things.

Scientists look at half-life decay rates of radioactive isotopes to estimate when a particular atom might decay.

Radioactive dating is helpful for figuring out the age of ancient things.

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.

However, rocks and other objects in nature do not give off such obvious clues about how long they have been around.

So, we rely on radiometric dating to calculate their ages.

Radioactive dating is helpful for figuring out the age of ancient things.

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.

However, rocks and other objects in nature do not give off such obvious clues about how long they have been around.

So, we rely on radiometric dating to calculate their ages.

So, if you know the radioactive isotope found in a substance and the isotope's half-life, you can calculate the age of the substance. Well, a simple explanation is that it is the time required for a quantity to fall to half of its starting value.