Hands-On Fossils

"Make a lasting impression with clay and plaster"

To learn about prehistoric life on earth, scientists search for and study fossils. Fossils are the remains of animals and plants preserved within the rocks that make up the earth's crust. Here's a hands-on activity that will teach your kids more about how these fossil treasures are created by letting them "fossilize" natural objects such as shells, leaves, or acorns.

 Items you'll need include:

  • small objects to fossilize,
  • modeling clay,
  • waxed paper,
  • plaster of Paris,
  • small amount of vegetable oil,
  • and a container for mixing.


Six easy steps to making fossils:

  1. For each item you'd like to fossilize, place a large ball of clay on a piece of waxed paper and flatten it into a thick circle.
  2. Now make an impression in the clay by gently pressing in the object and then removing it.
  3. Apply a small amount of vegetable oil to the impression surface to make it non-stick.
  4. Prepare some plaster of Paris according to the package directions so that it has a smooth but thick consistency.
  5. Spoon plaster into each impression thoroughly filling it in.
  6. Let the plaster dry completely (about 30 to 60 minutes), then peel away the "clay" to reveal your fossil.