Absolute dating of rocks and fossils
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 uranium-235 to lead-207 decay series is marked by a half-life of 704 million years.Carbon-14 is continually being created in the atmosphere due to the action of cosmic rays on nitrogen in the air.Carbon-14 combines with oxygen to create carbon dioxide.Radiocarbon dating, also known as carbon-14 dating or simply carbon dating, is a method used to determine the age of organic material by measuring the radioactivity of its carbon content.So, radiocarbon dating can be used to find the age of things that were once alive, like the Iceman.When the isotope is halfway to that point, it has reached its half-life.
There are different methods of radiometric dating that will vary due to the type of material that is being dated.
For example, how do we know that the Iceman, whose frozen body was chipped out of glacial ice in 1991, is 5,300 years old?
Well, we know this because samples of his bones and hair and even his grass boots and leather belongings were subjected to radiocarbon dating.
In fact, this form of dating has been used to date the age of rocks brought back to Earth from the moon.
So, we see there are a number of different methods for dating rocks and other non-living things, but what if our sample is organic in nature?
For example, uranium-lead dating can be used to find the age of a uranium-containing mineral.