Radiometric dating is used to estimate the age of rocks and other objects based on the fixed decay rate of radioactive isotopes.

When the isotope is halfway to that point it has reached its half-life.

There are different methods of radiometric dating that will vary due to the type of material that is being dated.

Radiometric dating, or radioactive dating as it is sometimes called, is a method used to date rocks and other objects based on the known decay rate of radioactive isotopes.

The thing that makes this decay process so valuable for determining the age of an object is that each radioactive isotope decays at its own fixed rate, which is expressed in terms of its half-life.

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.

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.