Different methods of radiometric dating can be used to estimate the age of a variety of natural and even man-made materials.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.
There are three main examples of this: i) Carbon dating - many natural substances contain two isotopes of Carbon. Types of rock (igneous) contain this type of uranium so can be dated, by comparing the amount of uranium and lead in the rock sample.
iii) Igneous rocks also contain potassium-40, which decays to a stable form of Argon.
The more radiation that is absorbed by the film the darker the colour it will go when it is developed. As the half-life is very long for Carbon-14, objects that are thousands of years old can be compared to new substances and the change in the amount of Carbon-14 can date the object.
This is useful for people working with radiation, they wear radiation badges to show them how much radiation they are being exposed to. Dating materials - The older a radioactive substance is the less radiation it will release. The half-life of the radioactive substance can be used to find the age of an object containing that substance. ii) Uranium decays by a series of disintegrations that eventually produces a stable isotope of lead.
So, we rely on radiometric dating to calculate their ages.