Radioactive dating activity middle school
Geologists draw on it and other basic principles ( to determine the relative ages of rocks or features such as faults.Relative age dating also means paying attention to crosscutting relationships.This method works because some unstable (radioactive) isotopes of some elements decay at a known rate into daughter products. Half-life simply means the amount of time it takes for half of a remaining particular isotope to decay to a daughter product. Good discussion from the US Geological Survey: geochronolgists just measure the ratio of the remaining parent atom to the amount of daughter and voila, they know how long the molecule has been hanging out decaying. So to date those, geologists look for layers like volcanic ash that might be sandwiched between the sedimentary layers, and that tend to have radioactive elements.What’s more, if the whole rock is badly weathered, it will be hard to find an intact mineral grain containing radioactive isotopes.
Unlike people, you can’t really guess the age of a rock from looking at it.Take students on a neighborhood walk and see what you can observe about age dates around you.For example, which is older, the bricks in a building or the building itself?After all, a dinosaur wouldn’t be caught dead next to a trilobite.The narrower a range of time that an animal lived, the better it is as an index of a specific time.
You might have noticed that many of the oldest age dates come from a mineral called zircon.