Hawai'i Space Grant Consortium, Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, 1996
To observe the effects of wind erosion on sand.
dry, fine sand
large cardboard box
small wood block
plastic or nylon mesh
Deserts and sandy coastlines are affected by wind that picks up and moves the fine sand and smaller particles. When wind-blown sand hits an obstacle, the sand can pile up into a mound or ridge called a dune. Dunes can also be moved, grain by grain, by the wind. What can be done when dunes threaten buildings?
- Place a large tray inside a large cardboard box on your work table. It's OK if part of the tray extends outside of the box. This cardboard box will act as a "shield."
- Cover the bottom of the tray with dry, fine sand. You have just created a beach.
- What will happen if a strong wind blows across the beach?
- From a distance of about 5 cm, each person in your group should take turns blowing from the same direction across the sand towards the back of the "shield" until the total number of blows reaches 50.
- Look at your beach and at the beaches made by the other groups. What are the effects of wind erosion?
- Reshape the beach and place a small, wood block down on the sand. This block represents a building.
- Again, blow the sand toward the block for 50 blows. What do you see happening?
- What can you do to stop the sand from covering the building?
- Use materials such as sticks, pebbles, or mesh to make a windbreak that is shorter than the building.
- Again, blow the sand toward the block for 50 blows. What do you see happening now?
- Compare your windbreak design and effectiveness with those made by the
other groups. Did any design work?
- Do you think it is possible to build an artificial barrier that will stop the erosion of dry, bare sand for a long time? Explain your answer.
- If windbreaks do not halt the erosion of dry, bare sand, what else could be done to reduce the effects of wind erosion?
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