WA.4. Earth and Space Science
ES3. Earth History
6-8.ES3. Evidence of Change: In prior grades students learned that fossils provide evidence of environmental conditions that existed long ago. In grades 6-8 students learn a few of the methods that have made it possible to uncover the history of our planet. This history includes both slow, gradual changes and rapid, catastrophic events, such as an asteroid or comet striking the Earth. It is possible to read a great deal of that history from rocks, including layers of sedimentary rock, some of which contain fossils. Understanding Earth's history is a valuable complement to the study of biological evolution.
6-8.ES3A. Students know that our understanding of Earth history is based on the assumption that processes we see today are similar to those that occurred in the past.
6-8.ES3A.1. Students are expected to describe Earth processes that we can observe and measure today (e.g., rate of sedimentation, movement of crustal plates, and changes in composition of the atmosphere) that provide clues to Earth's past.
6-8.ES3B. Students know that thousands of layers of sedimentary rock provide evidence that allows us to determine the age of Earth's changing surface and to estimate the age of fossils found in the rocks.
6-8.ES3B.1. Students are expected to explain how the age of landforms can be estimated by studying the number and thickness of rock layers, as well as fossils found within rock layers.
6-8.ES3D. Students know that earth has been shaped by many natural catastrophes, including earthquakes, volcanic eruptions, glaciers, floods, storms, tsunami, and the impacts of asteroids.
6-8.ES3D.1. Students are expected to interpret current landforms of the Pacific Northwest as evidence of past geologic events (e.g., Mount St. Helens and Crater Lake provide evidence of volcanism, the Channeled Scablands provides evidence of floods that resulted from melting of glaciers).