The Earth is a Changin'
Figure 1. An example of water erosion.Copyright U.S. Department of Agriculture, Natural Resource Conservation Service http://www.mo.nrcs.usda.gov/news/MOphotogallery/erosion.html
Students are introduced to the primary types of erosion—chemical, water, wind, glacier and temperature. Students investigate examples of each erosion type and discuss how erosion changes the surface of the Earth. Students also learn why engineers need to be aware of the different types of erosion in order to protect structures and landmarks from the damaging effects erosion can cause.
Civil engineers must carefully study the surrounding environment and soil composition to safely design and build any sort of structure on a piece of property. Buildings, roads and bridges require solid foundations and preferably land that is not prone to erosion (such as flood plains). Engineers also employ materials that resist erosion, such as water-proof materials or materials impervious to acid rain. Environmental engineers design surrounding landscaping to include trees and other vegetation in order to help prevent wind and water erosion since roots make soil more stable and less exposed to weathering forces. Engineers also design roads and sidewalks so that they may expand and contract with temperature changes without endangering the integrity of the structure, such as sidewalk "control joints" to control cracking.
After this lesson, students should be able to:
- List several different types of erosion.
- Describe several land formations that have been created by erosion.
- Explain how engineers learn about erosion to design or protect structures.