# Radiometric dating lesson plan dating site introduction line

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.

The thing that makes this decay process so valuable for determining the age of an object is that each radioactive isotope decays at its own fixed rate, which is expressed in terms of its half-life.

Scientist Britt Argow talks with teacher Joe Reilly about how scientists can determine the approximate age of a rock: comparing the relative abundance of naturally-occurring radioactive elements to their decay products.

Radioactive elements break down over time into another element at a known rate, called a "half-life." The "half-life" is the amount of time it takes for half of the radioactive element to change into another element.

The first lesson, Isotopes of Pennies, deals with isotopes and atomic mass.

Radiometric dating is sometimes referred to as radioactive dating.

In fact, you might like this term better, because the dating method relies on the known decay rate of radioactive isotopes.

Regardless of which name you prefer, the discovery was a true breakthrough that provided a tool to predict the geological history of the Earth and even the age of the Earth itself.

To better understand how radiometric dating helps us determine the age of rocks, it will help us to gain a better understanding of how elements decay.