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Arizona Activity Page


Fossils are plant and animal remains preserved and embedded in rocks. Arizona has many fossil sites that help scientists understand the Earth’s history. Fossilized tree stumps in Petrified Forest National Park, for example, attract many paleontologists studying ancient environments. Make a fossil of your own with this fun activity!

Create a Fossil

Create a Fossil


  • Modelling clay
  • Plaster of Paris
  • Small objects to fossilize (an acorn, leaf, seashell or chicken bone)
  • 2 paper cups
  • Water
  • 1 tsp vegetable oil


  1. Flatten a small ball of modelling clay to make it about one inch think. Smooth the top of the ball.
  2. Put the modelling clay inside a paper cup with the smooth side facing up.
  3. Press the object you want to fossilize into the modelling clay so the object creates a deep impression.
  4. Remove the object from the clay.
  5. Moisten the impression with some vegetable oil.
  6. Pour half a cup of plaster of Paris into the second paper cup. Add 1/4 cup water to the plaster and stir well. Wait for 2 minutes.
  7. Pour the plaster mixture into the first cup with the modelling clay. Don?t mix. Wait for 30 minutes, or until the plaster has dried.
  8. Tear the sides of the cup and peel away the clay. Enjoy your fossil!