For example, fission track dating measures the microscopic marks left in crystals by subatomic particles from decaying isotopes.Another example is luminescence dating, which measures the energy from radioactive decay that is trapped inside nearby crystals.
The half-lives of several radioactive isotopes are known and are used often to figure out the age of newly found fossils.
Different isotopes have different half-lives and sometimes more than one present isotope can be used to get an even more specific age of a fossil.
Others measure the subatomic particles that are emitted as an isotope decays.
Some measure the decay of isotopes more indirectly.
All radiometric dating methods measure isotopes in some way.
Most directly measure the amount of isotopes in rocks, using a mass spectrometer.
One way that helps scientists place fossils into the correct era on the Geologic Time Scale is by using radiometric dating.
Also called absolute dating, scientists use the decay of radioactive elements within the fossils or the rocks around the fossils to determine the age of the organism that was preserved.
As radioactive isotopes of elements decay, they lose their radioactivity and become a brand new element known as a daughter isotope.
By measuring the ratio of the amount of the original radioactive element to the daughter isotope, scientists can determine how many half-lives the element has undergone and from there can figure out the absolute age of the sample.
When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.