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8th Grade Core
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Weathering and Soil Formation

Rocks can be sedimentary, metamorphic or igneous. Igneous rocks form as a result of liquid rock becoming a solid. Without the forces that change rocks, they would stay as large solids for years.

However, in the Weathering and Erosion Sci-ber text page, you learned how rocks are broken down into smaller pieces. When one rock splits it forms two or more smaller rocks. Smaller rocks have a larger surface area than the larger rock did. A greater surface area allows weathering to happen more rapidly.


As various weathering agents work on rocks, the rocks are slowly broken down. Look closely at the photograph at the right. You should notice that the sedimentary rocks are found in layers. There is some snow on the rocks. Some of the snow is melting. The snow and water help to break down this sedimentary rock and form small pieces of soil.

The evidence that some soil is present is found in the plants which appear to be growing "out" of the rock. In reality, these plants have roots that are growing in soil that is located in the cracks of the rock.

Visit Pioneer Library and search for the e-Media video "Earth Science Collection: Getting To Know Soil."
You can demonstrate how weathering is related to soil formation in the following activity.


  • Safety goggles
  • Rock
  • Large container
  • Rock hammer
Safety concerns: Be sure to keep all eye safety rules. As with all science lab activities, the most important safety rule is to follow all teacher directions.


  1. Put on your safety goggles.
  2. Place the rock into the large container.
  3. Begin to hit the rock with the rock hammer.
  4. When pieces break off the rock, compare the size of these pieces with the original rock.
  5. Begin to hit the rock pieces with the rock hammer.
  6. See how close you can get to sand grain size pieces!


  1. How many hits did you have to use to be able to create sand size grains?
  2. How long did it take to form the sand size grains?
  3. How long do you think it takes for nature to take a rock and turn it into sand size grains?

Review Science safetey rules here.

Get the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 8th grade science core.

Updated October 24, 2008 by: Glen Westbroek

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