Scavenger Hunt

This lab deals with many specific fields in geology: geomorphology, mineralogy, geochemistry, economic geology, mining geology, geological engineering as well as a few shared field like astrology and paleontology. One aspect of geology that is difficult to understand and easy to dismiss is how geologists decide how old a rock is, click HERE for the simulation. Before we get into dating methods though, we will need to go over some definitions.

Half life- The amount of time it takes for the amount of atoms to fall to half of the original number. The half life of unstable or radioactive atoms are different between each element, so lead will have a different half life of carbon. A half life can be renewed as one half life is complete, so a second half life starts after the first is done.

Radioactive Decay- The process by which an unstable atom releases energy by emitting radiation. The radiation can be in the form of smaller atoms, releasing protons or converting protons into neutrons.

From the page that opens with the link, click the "play" button. The first page is to help you understand a half life, so let's start with carbon-14. Click the "Add 10" button on the bucket of atoms a few times. Do you see how the atoms spontaneously change from carbon-14 to nitrogen-14? How quickly the carbon-14 changes depends on how long the half life is.

Now click on the second tab, labeled "Decay Rates". This time let's work with uranium-238, so select that option on the right. Use the scroll bar on the bucket to add any amount of uranium-238 you would like. Then watch the graph at the bottom which will help you see that as the uranium-238 decays to lead-206, geologists can figure out how old a rock is.

Hopefully you've learned a bit more about radiometric dating techniques. If you have more questions, ask one of your teachers or check back to this website every once in a while!