How to Make A Quick and Easy Fossil

Some fossils are actual living objects that have turned to rock; other fossils are impressions that are filled in with mineral deposits.

Fossils fascinate children. Seeing an impression left by something that existed millions of years ago is an incredible -- and often confusing -- concept to fully comprehend. Teach children how fossils are made by giving them a hands-on project that allows them to create their own "fossil" in less than an hour. This project is appropriate for children ages eight and older.

Things You'll Need

• Disposable tray, such as a 9 by 13-inch aluminum foil cake pan or a clean kitty litter pan
• 1 bag of clean play sand
• 1 cup of water
• 2 cups of quick-setting plaster of Paris
• Sea shells or other small, firm objects
• Disposable plastic spoon (optional)

Instructions

1. Set the pan on a work surface that can get dirty. Let children pour in the play sand until it is about two inches deep. Help them sprinkle the sand with water until it becomes damp and holds a shape, such as you would when making a sand castle. It should have the consistency of oatmeal.

2. Have children take the sea shells, or any other firm object or toy such as a rubber dinosaur, star fish or toy figure, and press it firmly into the damp sand to create an impression. Carefully remove the item to avoid disturbing the sand around it. The cavity left will become the mold for the fossil.

3. Mix the plaster of Paris as directed on the container. Immediately pour the plaster mixture into the sand impressions. Be careful to keep the plaster only in the impression; it may be easier to use a disposable plastic spoon to put the mixture into smaller molds.

4. Let the plaster dry for 45 minutes or until hardened. Remove the fossils from the sand.

Tips & Warnings

• If you want to make the fossil a certain color, mix 1 tablespoon of powdered tempera paint to the plaster before adding water.

• You can paint your fossils with ceramic paints. Let them dry completely before painting.

References

• Drs. Cavanaugh: Fossils and fossil types
• Backyard Nature: Backyard Fossils