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.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.Free 5-day trial 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.The methods work because radioactive elements are unstable, and they are always trying to move to a more stable state. This process by which an unstable atomic nucleus loses energy by releasing radiation is called radioactive decay.
When they die no new carbon-14 is taken in by the dead organism.
So, we start out with two isotopes of uranium that are unstable and radioactive.
They release radiation until they eventually become stable isotopes of lead.
As a result, rocks that record its earliest history have not been found and probably no longer exist.
Nevertheless, there is substantial evidence that the Earth and the other bodies of the Solar System are 4.5-4.6 billion years old, and that the Milky Way Galaxy and the Universe are older still.