Scientists look at half-life decay rates of radioactive isotopes to estimate when a particular atom might decay.

A useful application of half-lives is radioactive dating.

It then takes the same amount of time for half the remaining radioactive atoms to decay, and the same amount of time for half of those remaining radioactive atoms to decay, and so on. The amount of time it takes for one-half of a sample to decay is called the half-life of the isotope, and it’s given the symbol: It’s important to realize that the half-life decay of radioactive isotopes is not linear.

For example, you can’t find the remaining amount of an isotope as 7.5 half-lives by finding the midpoint between 7 and 8 half-lives.

Scientists know the half-life of C-14 (5,730 years), so they can figure out how long ago the organism died.