HS-ESS1-5

Evaluate evidence of the past and current movements of continental and oceanic crust and the theory of plate tectonics to explain the ages of crustal rocks.

A Model of Three Faults

One of the most frightening and destructive phenomena of nature is a severe earthquake and its terrible aftereffects. An earthquake is a sudden movement of the Earth, caused by the abrupt release of strain that has accumulated over a long time. For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as the huge plates that form the Earth's surface slowly move over, under and past each other. Sometimes the movement is gradual. At other times, the plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free. If the earthquake occurs in a populated area, it may cause many deaths and injuries and extensive property damage.

Dating Popcorn

How do geologists understand the Earth’s history? In part, they measure the age of rocks and other natural materials by dating techniques. They can date rocks by gauging the amount of decay of radioactive elements. You can simulate the dating process with popcorn.

Grow Your Own Crystals

Most minerals happen naturally as crystals. Crystals are made of specific atoms or molecules joined to make distinctive repeating patterns. The crystals that make up many kinds
of minerals are formed deep underground through the interaction of fluid, pressure, and temperature. Some minerals form at or near the surface. You may have seen spectacular mineral samples in museums, but you might not be aware that minerals are everywhere, including in your body.

Visualizing Your Watershed

Watersheds can be as small as a lake or thousands of square miles. The natural or human-made surface of the land and the sediments and rocks below are all part of a watershed. Rainfall
supplies watersheds, and water moves across the surface or infiltrates and moves through the ground.

In this activity you will use a computer model to explore the movement of water within your watershed.

Materials

• Computer with internet

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