Radiometric method for dating rocks
The half-life of carbon 14, for example, is 5,730 years.On the other hand, the half-life of the isotope potassium 40 as it decays to argon is 1.26 billion years.Take the FREE & fun all about Layers of Rocks quiz and download FREE all about Layers of Rocks worksheet for kids.
If you look at a cliff made from sedimentary rock, you’ll notice distinct layers that may even be different colors.Activity: Further discussion: Good overview as relates to the Grand Canyon: age dating: Use with this cross section of the Grand Canyon from the USGS’s teaching page: Canyon Have students reconstruct a simple geologic history — which are the oldest rocks shown? Are there any that you can’t tell using the Rule of Superposition?I also like this simple exercise, a spin-off from an activity described on the USGS site above.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?
With absolute age dating, you get a real age in actual years.