Geologic Time
Comments
Contributed By
- Original Source:U.S. Geological Survey
Conditions of Use:None Specified
Description
The Earth is very old -- 4.5 billion years or more -- according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science. Less
Learning Registry Activity
Bookmarks
Topics and Grades
Grade: TK/K to 9
Topics: Earth's Resources, Evolution and Adaptation, Earth & Space Science, Geology & the Dynamic Earth
Resource Pedagogy
Resource Type/Classification:
- Interactives
Tool for: Students