American Geosciences Institute
American Geosciences Institute: How Can We Tell How Old Rocks Are?
Find out how scientists can find out the age of the rocks they are studying.
US Geological Survey
Usgs: What Is Geologic Time?
Understand the evidence for ancient earth and the geologic time scale. Learn on this site how the earth can help scientist date discoveries.
Science Struck
Science Struck: Relative vs. Absolute Dating
Explains what relative and absolute dating are and some different methods used for each. A Venn diagram is presented showing what characteristics they share and how they differ.