As we have mentioned before each radioactive isotope has its own decay pattern.Not only does it decay by giving off energy and matter, but it also decays at a rate that is characteristic to itself.Scientists can use the half-life of Carbon-14 to determine the approximate age of organic objects less than 40,000 years old.By determining how much of the carbon-14 has transmutated, scientist can calculate and estimate the age of a substance. Isotopes with longer half-lives such as Uranium-238 can be used to date even older objects.
They allow us to determine the ages of very old artifacts.
The rate at which a radioactive isotope decays is measured in half-life.
The term half-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate.
Let's look closely at how the half-life affects an isotope. Therefore, after one half-life, you would have 5 grams of Barium-139, and 5 grams of Lanthanum-139.
After another 86 minutes, half of the 5 grams of Barium-139 would decay into Lanthanum-139; you would now have 2.5 grams of Barium-139 and 7.5 grams of Lanthanum-139.
After one half-life of a given radioisotope, only one half as much of the original number of atoms remains active.