How Are Rocks Classified?
Materials Needed
A collection of rocks
Encyclopedia
Other reference books as available
Procedure
1. Gather a collection of rocks.
2. Classify (sort) the rocks by putting them into groups
according to their color.
3. Do the rocks have different textures? Are some rough, some smooth,
some shiny, and some dull? If so, classify them again according to their
texture.
4. As you lift the rocks, do they all seem to have about the same weight
relative to their size? If not, classify them again according to density (the
weight relative to the size).
5. Look at the rocks carefully and see whether you can think of any other
characteristics you could use to classify them. If you think of any, sort the
rocks again by those characteristics.
6. Look up “rocks” in an encyclopedia or other reference books and find out
what characteristics geologists use to classify rocks. See whether you can
determine some of the types of rocks in your collection.
7. Answer the questions below:
What are some ways you grouped your rocks? _______________________________
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What is something interesting you learned about rocks from your reading?
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Adapted from Hands-On Science Activities by Marvin N. Tolman