Wednesday, October 28, 2009

Science: Weathering and Erosion

Weathering - the breaking and changing of rocks

water and ice can cause weathering
plants can cause weathering when their roots push the rocks apart
Erosion - the moving of weathered rocks and soil by wind, water or ice

wind erosion can build up large piles of sand called dunes
glaciers move downhill, moving soil and rock with them and in front of them
Controlling Erosion

can be helpful when it helps form new soil or build up new land
problems:
a. washes away soil from farmlands
b. can also wash away roads and ground under homes
how farmers control erosion
a. plant strips of grass and clover (cover crops) between crops to help absorb rainwater
b. plow fields in rows around hills to allow rainwater to settle and not flow downhill
c. planting trees on steep hills to hold down the soil and protect it from wind

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