Teaching relative age dating
In fact, Paul already knows that coelophysis lived around 200 million years ago, while iguanodon lived around 150 million years ago.
So, what if Paul found that superus awesomus dinosaur fossil in this middle layer?
Scientists piece together a story of how one event came before or after another.
Relative dating cannot tell us the actual age of a rock; it can only tell us whether one rock is older or younger than another.
Recently, he appeared on the evening news to talk about a new dinosaur he just discovered. Paul says he can tell from the fossils that superus awesomus lived on Earth about 175 million years ago.
Paul is super awesome, so I'm going to take him at his word.
In 1905, Ernest Rutherford figured out that we could use radiation to establish the ages of rocks.
By studying how the mass of uranium changed with radioactive decay, Rutherford was able to determine the age of a rock containing a uranium mineral. It meant that scientists could suddenly establish the actual ages of all their rocks and fossils!
This is just a fancy term for the way rock layers are built up and changed by geologic processes.
Scientists are always spouting information about the ages of rocks and fossils. Well, they figure it out using two different methods: relative dating and numerical dating.
Let's find out more about these geological dating methods in order to understand how Paul the Paleontologist can be so sure about the age of his dinosaur fossils.
Let's say that Paul the Paleontologist found an iguanodon fossil in the light green layer shown above.
And, he also found a coelophysis fossil in the yellow layer. Of course, the coelophysis, which means that coelophysis came before iguanodon.