• For fossil print clay: 1/2 cup of salt; 1 cup flour; 1/2 cup brewed coffee; 1 cup used coffee grounds (enough for four participants)
• Mixing bowl(s) and spoon(s), measuring cups
• "Fossils" to imprint such as chicken bones, twigs, seashells, acorns, and plastic toy dinosaurs (skin textures and footprints)

• Decide whether you will have participants make fossil prints, and/or hunt for and analyze fossil prints that have already been prepared. The clay should be imprinted soon after preparation. It dries in 24 hours.
• Prepare clay, multiplying quantities of the ingredients as needed to supply everyone in your group: Measure salt, flour, coffee, and grounds into a bowl. Stir together until well mixed. Turn the dough onto a large sheet of waxed paper and knead it until smooth.
• Make a fossil imprint: Break off a piece of clay large enough for the imprint you want to make. Roll it into a ball and use the heel of your hand to flatten it. Press the object(s) you wish to make a fossil imprint of firmly into the dough. Carefully remove the objects to leave the prints behind. Let your fake stone dry overnight and you have an imitation fossil!

This activity replicates the way real fossil prints were created. The activity was developed by University of Michigan's Reach Out! project, which gives permission for anyone to use their materials but not to sell them. The Reach Out! project is dedicated to pairing mentors with children and youth.

A long time ago, plants, bugs, or animals left impressions in soft mud, which dried out and eventually became rock. Much of our knowledge about ancient, extinct plants and animals comes from fossil prints. For example, fossil prints have shown us the texture of dinosaur skin and helped us trace the evolution of birds, since neither skin nor feathers are likely to survive as actual fossils, the way bones do.

Ask participants to identify what they have uncovered. Follow up with questions such as:

• Did you feel like a paleontologist (someone who looks for fossils)?
• Have you ever found a real fossil?

Clay made with wheat products can be irritating to those with allergies. There are gluten-free clay products available.