Group During experiment, teacher will circulate and observe individual students at work within the groups. Notice will be made of group cooperativeness, and the group's ability to stay on task, ask interesting questions, and make relevant observations. Individual Data sheets will be evaluated for completeness, thoughtfulness of explanations and insights, and neatness. Erosion is the wearing away of rock or soil by running water, waves, windblown sand, or glacial action. Moving water is one of the most important forces that makes land disappear.
Water erosion can make sharp mountains turn into rounded hills, then into flat plains.
Another kind of erosion is caused by ice. Glaciers are deep layers of ice that can move slowly across the land like a great frozen river. As they go, they pick up rocks which scrape away at the land below. The blowing wind, especially when it carries sand, can erode away rocks like a giant sandblast. Blowing winds can also pile sand into lofty dunes and remove essential topsoil for growing crops.