Activity 2: Do at School!

What Doesn't Belong?

Take a walk around your school and collect rocks.


[Different kinds of rocks you might find]

Teacher background:

  1. Most of the rocks we find in Central New York are grayish rocks made of sediment (sand, lime, and mud) laid down at the bottom of a shallow sea a long time ago.
  2. We also find colorful rocks with crystals.
  3. Colorful crystal rocks are very common in the Adirondack mountains in northeastern New York and in southern Canada.
  4. During the Ice Age glaciers scraped southward from Canada, and, like bulldozers, they pushed colorful crystal pebbles and boulders along in front of them.
  5. When glaciers melted they left these colorful pebbles behind.
  6. These pebbles are called "glacial erratics", and they are unlike most of the rocks found in this area.


  1. Take a walk and collect several small rocks from around the school.
  2. Sort the rocks into three categories:
    1. Gray rocks - these are rocks made of sediment. Some might even contain fossils!
    2. Colorful crystal rocks - these are rocks that may have been carried to your neighborhood by a glacier 12,000 years ago.
    3. Mystery rocks - these may be pieces of concrete or rocks carried into your neighborhood by people.

How many colorful rocks did you find?

How many gray rocks did you find?

Did you find any rocks with fossils in them?

Did you find any mystery rocks?

Main Message: Classifying rocks can answer questions about the history of an area.

Connections: Activity 7, "Ice Age Mud," will allow students to classify rocks and fossils from the sediment surrounding a Mastodon.



The Paleontological Research Institution
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Ithaca, NY 14850 phone: 607-273-6623 fax: 607-273-6620
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