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. In part, they measure the age of rocks and other natural materials by dating techniques.They can date rocks by gauging the amount of decay of radioactive elements.This decay is an example of an exponential decay, shown in the figure below.
There is no going back – the process is irreversible. When we pour our popcorn kernels into a popcorn popper, the is no way to know which will pop first.
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.
Radioactive decay involves the spontaneous transformation of one element into another.
The only way that this can happen is by changing the number of protons in the nucleus (an element is defined by its number of protons).