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

Learn about half-life and how it is used in different dating methods, such as uranium-lead dating and radiocarbon dating, in this video lesson. As we age, our hair turns gray, our skin wrinkles and our gait slows.

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.

You would need to have access to scientific instruments at this point that could measure the amount of radioactivity in the sample, so off to the lab we go!

After you prepare your sample and put it into the machine, your read-out says you have approximately 75% Nitrogen-14 and 25% Carbon-14.

After two half-lives, another half of your leftover Carbon-14 would have decayed into Nitrogen-14.

Half of 50% is 25%, so you would have 25% Carbon-14 and 75% Nitrogen-14.

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.

One way that helps scientists place fossils into the correct era on the Geologic Time Scale is by using radiometric dating.

Also called absolute dating, scientists use the decay of radioactive elements within the fossils or the rocks around the fossils to determine the age of the organism that was preserved.

spontaneous decomposition of the nuclei of the atoms of radioactive substances.