erosion jug

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Home : 2005 : May : 28

erosion jug
By nmrose

Use two clear PLASTIC gallon jugs with good lids. Label the first jug "igneous" and select several basalt or granite rocks similar in size and color with the rocks in the second jug. Label the second jug "sedimentary" and
fill with soft sedimentary rocks similar in size and color with the igneous rocks. Fill both jugs approximately 1/3 full with water. Have students write their observations and hypothesis before going outside.
Now go outside and apply an erosional force.
Have each student shake each jug as hard as they can fifty times. Let them count out loud as they shake the jugs and the rocks bump

against each other. Explain that water is one of the greatest constant erosional forces in nature, and that all over the world, twenty-four hours a day, moving water applies erosional force on rocks and breaks it down into smaller parts, then carries away the broken bits as sediment to become ocean deposit.
Explain how the hardness of rocks effects their rate of erosion. Have students write their observations and conclusion comparing the two jugs after the "Great Shake-Down".