Describe absolute dating and relative dating
Although catastrophism geology is alive and well among many geologists, currently the word geology connotes uniformitarianism.A scientist measures the rate of a reaction between two liquids.Before radiometric dating (or other methods of absolute dating like counting tree rings) it was difficult to determine the actual age of an object.
As far as describing the method with the lava and whatever, I don't know how to answer the second party, really.
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.
A sedimentary deposit is layer upon layer of mud or other fine particulate that eventually turns to rock. In some places on the Earth these sedimentary deposits have been uncovered in such a way that you can see dozens of layers stacked one on top of the other.
The concept in relative fossil dating is that the fossils on the bottom layer are the oldest and the fossils in the top layer are the youngest.