Rocks and Minerals > Rock Cycle Activities

Physical Weathering: Wind Erosion

by Deborah Hanuscin

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Note: Step 1 below will need to be done outdoors.

Concept: Wind erosion

Some rocks that are composed of soft minerals or are composed of particles that are not well cemented may break down when struck by windblown sand or smaller-sized particles.

Objective:

Students will be able to describe what happens to rocks that are eroded by the wind.

Materials:

• pie pan
• fine sand
• electric fan
• extension cord (if no outdoor outlet)
• sheets of sandpaper, a "soft" rock such as limestone
• a "hard" rock such as granite
• various samples of rock

Procedure:

1. Place a pie pan of fine sand in front of an electric fan outdoors. Turn the fan on. What happens? What would a very strong wind do to the sand? What would happen if the sand hit some clay? What would happen if it hit a rock?
2. Rub a sheet of sandpaper across several different types of rocks. How is this like windblown sand striking a rock? How is it different?
3. Select a "hard" rock such as granite and a "soft" rock such as limestone. Rub each one with sandpaper 100 times and record your observations. What happened to each rock?
4. Repeat your observations using several types of rocks.

The force of the wind can change the surface of the earth on a small scale by removing materials and abrading rock surfaces. These conditions may be more noticeable where land is dry and unprotected by plants. For example, in the desert you may see rocks with their tops worn smooth.

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