Journal: Erosion
For this activity, you need some backyard soil or purchased potting soil, an aluminum baking dish, water in a spray bottle, a stack of books, and enough leaves or straw to cover the entire area of your baking dish. As you complete each step below, notice how simulated rainwater disturbs the soil surface under different situations.
1. Fill your baking dish about half full with soil. With the baking dish flat on a table, spray water over the soil to simulate rain falling on the soil. Vary the force with which the water comes out, so that you can compare what happens when the "rain" drops are small and gentle versus when they are larger and fall with more force. Note how soil disturbance varies under each condition.
2. Next, cover the surface of the soil with the leaves or straw. Make sure the soil surface is completely covered. Spray "rain" over the soil and note how much the soil is disturbed this time.
3. Finally, remove the leaves or straw from the soil, and use the stack of books to prop up one end of the dish. Again, apply "rain" to the soil surface at a few different levels of force and observe how soil disturbance compares on the sloped soil to when the soil was flat.
For each situation above, please write your journal entry in the Journal template. You will submit your journal at the end of this unit. In your journal entry, be sure to answer the following questions:
1. How does soil disturbance due to raindrops compare for bare soil and soil covered with vegetation? How can keeping a soil covered with plants help minimize disturbance of the land?
2. How does slope affect the movement of soil particles during a rainstorm? What could you do to minimize soil disturbance on sloped land?