Materials
16-oz. box baking soda 1 cup cornstarch 1 1/4 cup cold water hot plate or stove mixing spoon container variety of small seashells
Instructions
1. Make soda clay beforehand. Mix together the box of baking soda and 1 cup of cornstarch. Add 1 1/4 cup of cold water. Stir over moderate heat until mixture thickens and resembles mashed potatoes. Scrape onto a plate and cover with a damp cloth. When cool enough to handle, knead until smooth. Keep in a tightly covered container.
2. Read a book about fossils and discuss.
3. Give each child a lump of soda clay to make a "fossil."4. Demonstrate how to press shells into the clay to leave a print.
5. Carefully remove the shells from the clay.
6. Allow the "fossils" to dry thoroughly.
7. Ask the children to count the number of imprints in the hardened clay. Compare the sizes of the shells. Can they find the shells that match the prints?
