Thursday, April 11, 2013

Erosion

Teaching our children about forces that can change the Earth's surface today. After watching a PowerPoint of before and after land forms, Mrs. Ruark unveiled the lab. They discussed the rocks, sand, clay and humus that they saw on the slanted board.  Then children were off to their journals to draw the "before" landscape,  Finally they predicted what they thought would happen if we added air and/or water.



The students then gathered so they could watch and participate in each step of the lab.  Just sitting the students so everyone can easily see is a management technique!


We started with a little air through a straw.  The children noticed that the sand moved around just a little as the child blew a little stream of air.
Next the wind picked up a little and the students noticed that much of the sand moved, but the rocks, clay and grass stayed put.
A spray bottle provided the light rain.  The children noticed that the water made the dirt a little darker so that it looked a little like mud but didn't really move the soil around.


Then finally it was a flash flood!

And the children watched as the water moved much of the sand, clay and even rocks.  They also decided that the grass stayed put because  the roots helped to keep the hummus in place.

After an excited discussion, the children went back to their journals to write the conclusion to the experiment, observing the air and water can move soil.

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