Geologist uses radiometric dating
The technique measures the radioactivity of carbon 14 in a biological sample that may have been preserved for hundreds of years or tens of thousands of years.Knowing that the carbon 14 has a half life of 5,730 years allows the estimation of the age of the object based on the fraction of carbon 14 remaining.nts and thus many applications of the basic principle.Examples: Archeologists may employ the well known method of carbon 14 dating.
For example, with potassium-argon dating, we can tell the age of materials that contain potassium because we know that potassium-40 decays into argon-40 with a half-life of 1.3 billion years.
These two uranium isotopes decay at different rates. The half-life of the uranium-238 to lead-206 is 4.47 billion years.
The uranium-235 to lead-207 decay series is marked by a half-life of 704 million years.
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.