When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.
Isotopes are important to geologists because each radioactive element decays at a constant rate, which is unique to that element.
Isotopes of a particular element have the same number of protons in their nucleus, but different numbers of neutrons.
This means that although they are very similar chemically, they have different masses.
What methods do they use and how do these methods work?