Radiometric dating using isotopes
See the background information on Students will use half-life properties of isotopes to determine the age of different "rocks" and "fossils" made out of bags of beads.
The majority of the time fossils are dated using relative dating techniques.The same rock formation also contains a type of trilobite that was known to live 415 to 425 million years ago.Since the rock formation contains both types of fossils the ago of the rock formation must be in the overlapping date range of 415 to 420 million years.Matter is made of minute particles called atoms, and atoms are composed of even smaller components.These components have measurable properties, such as mass and electrical charge.Carbon-14, the radioactive isotope of carbon used in carbon dating has a half-life of 5730 years, so it decays too fast.
It can only be used to date fossils younger than about 75,000 years.
Then after another 5,000 years half of the remaining parent isotope will have decayed.
While people are most familiar with carbon dating, carbon dating is rarely applicable to fossils.
This uses radioactive minerals that occur in rocks and fossils almost like a geological clock.
It’s often much easier to date volcanic rocks than the fossils themselves or the sedimentary rocks they are found in.
Scientists can use certain types of fossils referred to as index fossils to assist in relative dating via correlation.