America Geophysical Union. Adapted with permission.
Various types of sediments, or “surficial features,” lie above the bedrock in many places. The U.S. Geological Survey provides a map illustrating this phenomenon at http://pubs.usgs.gov/of/2003/of03-275/.
“Most daily human activities occur on or near the Earth’s surface,” as the introduction to the map states. “Homeowners, communities, and governments can make improved decisions about hazard, resource, and environmental issues, when they understand the nature of surficial materials and how they vary from place to place.”
Using this map can help students see the connections between those surficial features, which are generally part of the geosphere, and other Earth systems. The following activity shows how a visualization map of surficial features can be used to consider the interactions of the geosphere, hydrosphere, biosphere, and atmosphere.
For each student group:
- Computer with internet connection
- Three clear plastic cups
- Enough of each type of sediment material — soil, sand, and gravel — to fill a plastic cup roughly halfway
- Small container of water (about a half-gallon)
- Measuring cup
- Pen and paper
- View the map and legend at http://pubs.usgs.gov/of/2003/of03-275/. Notice that different colors represent different types of surficial features (sediments). The map colors indicate types of sediments that differ in size, material, textures, amount of organic material, and so on. The map legend tells about various surficial feature materials.
- Discuss: What are areas with similar surficial features? Where are there surficial features that seem to be related to features such as coastlines, mountains, or rivers? How might we model the interaction of rain, streams, and oceans with various sediments?
- Within your group, fill three clear plastic cups equally, about halfway, with a different type of sediment (soil, sand, and gravel). Describe the sediments in the cups. How are they different?
- Fill a measuring cup with water. With a pen and paper, record the amount of water in the measuring cup. Pour some into one of the clear plastic cups, adding water until it is just above the level of the sediment. Record the amount of water now in the measuring cup. Calculate the amount of water poured over sediment in the clear plastic cup. Repeat this process for each sediment.
- Discuss: For which type of sediment does the most water go into the cup? (Typically, larger sediments allow more water in.) How can water go into the sediments? (It seeps into spaces between particles.)
- Consider the sediment cups as models of surficial features. How might the different surficial features affect the amount of water (hydrosphere) available to plants (biosphere)? (In general, when water seeps into the sediments, it is available to plants.)
- Now, return to the U.S. Geological Survey map online. What surficial features do you see in your part of the country, near major rivers, and along coastlines? Why do you think these patters occur?
For an activity relating to surficial features that you can do in the school yard, go to GLOBE at http://www.globe.gov/documents/352961/41672784-81d0-4189-81f4-280acaa3364d. To explore the effects of surficial features in your community, use Yardmap tools at http://content.yardmap.org/.