A useful application of half-lives is radioactive dating.This has to do with figuring out the age of ancient things.For example, in 1991, two hikers discovered a mummified man, preserved for centuries in the ice on an alpine mountain.
We could be sure that a mineral containing parentium originally had no daughterium.
The carbon-14 it contained at the time of death decays over a long period of time.
By measuring the amount of carbon-14 left in dead organic material the approximate time since it died can be worked out.
Knowing about half-lives is important because it enables you to determine when a sample of radioactive material is safe to handle.
Radioactive dating is a method of dating rocks and minerals using radioactive isotopes.