History of Earth

Model of a Normal Fault

A normal fault occurs when rocks break and move because they are being pulled apart. As the area is stretched, the rocks move along the fault. Each movement causes an earthquake. This model demonstrates how a block of rock is extended by a normal fault.

Modeling Earthquake Waves

An earthquake occurs when massive rock layers slide past each other. This motion makes enormous vibrations, which travel from the site of the earthquake in waves. In this activity, you will model how earthquakes move in three dimensions.

Parks Past, Present, and Future

Over Earth’s 4.5 billion-year history, tectonic upheavals and colliding plates formed mountain ranges and carved out basins. Forces of erosion and weathering have been at work to break down these landforms. Records of these processes are imprinted on the land and define distinctive landscapes around the United States and in its national parks.

Rock Abrasion

Rocks break down into smaller pieces through weathering. Rocks and sediment grinding against each other wear away surfaces. This type of weathering is called abrasion, and it happens as wind and water rush over rocks. The rocks become smoother as rough and jagged edges break off. In this activity, you will model how abrasion works.

Shoebox Geologist

Earth processes such as volcanic eruptions, floods, landslides, and glaciers leave behind evidence of their passing in the form of layers known as deposits. By studying deposits of recent geologic events, geologists are able to better understand older deposits and identify the processes that caused them.

Sinkholes in a Cup

In this activity, learn how sinkhole formations in rocks form and the danger they pose to communities.

Soil, the Forgotten Resource

Soil is often overlooked as a natural resource. Like fossil fuels, we depend on it for energy in the form of foods. And, like fossil fuels, it is nonrenewable. Soil is a delicate balance of inorganic minerals, organic matter, living organisms, soil water, and soil atmosphere. The natural development of soil is an exceedingly slow process. In a few hours, a heavy rain falling on exposed soil can remove inches of what took hundreds of years to form. Here is a simple exercise that will allow you to compare the rates and amounts of erosion that result from various land uses.

Take the Pulse of Your Classroom

The following activity can leverage SeisMac technology to help students understand how a seismometer records ground motions.

The EarthTrek Gravestone Project

The Gravestone Project, part of the global citizen science program called EarthTrek (www.goearthtrek.com), is seeking volunteers to visit cemeteries around the world and collect scientific data on how marble gravestones are weathering.

Third From the Sun

In 1972, NASA launched a special satellite called Landsat that contained a new camera designed to take pictures of the Earth. Why was this satellite so incredible? Well, it could take a series of pictures of almost the entire Earth over and over again, season after season, month after month, year after year. You will be seeing Landsat images in this activity and learn how to interpret them.


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