University of California
Ucmp: A Relative Dating Activity
An learning activity to help students grasp the concept of relative dating and geologic time.
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 Education Resource Center at Carleton College
Serc: American Field Guide: Relative Dating Telling Time Using Fossils
This website integrates video footage and information with lesson plans and activities to teach students about the concept of relative dating. Students will graph a range chart for ammonites, determine the geologic age for several rocks,...
Other
Utah Geological Survey: How Do Geologists Know How Old a Rock Is?
Geologists generally know the age of a rock by determining the age of the group of rocks, or formation, that it is found in. The age of formations is marked on a geologic calendar known as the geologic time scale. Development of the...
Georgia Department of Education
Ga Virtual Learning: Historical Geology
In this interactive tutorial you will explore how geologists use clues in rocks to determine the order in which rocks formed. Learn how principles of radioactivity are used to assign actual ages to rocks. Students will explore fossils...
TED Talks
Ted: Ted Ed: Four Ways to Understand the Earth's Age
The Earth is 4.6 billion years old- but how can humans relate to a number so colossal, and where do we fit on the geologic timeline? Joshua Sneideman reminds us of our time and place in the universe. [3:45]