- Grade Level:
- Lower Elementary: Pre-Kindergarten through Second Grade
- State Standards:
- ESS1.C, LS4.A
Most land-based animals and plants never become fossils. Most sediment is laid down in seabeds, which cover animals that lived and died at sea. For this reason most fossils come from sea creatures.
The limestone in which Wind Cave was formed was laid down in a shallow sea around 300 million years ago. In this ocean lived many sea creatures such as brachiopods (clam-like animals), coral, and sponges. When these organisms died the shells and coral built up and turned to limestone. A fossil was made when an organism died and its body settled into the sediments on the sea floor. More sediment covered the organism; and over time, the organism became rock.
- Some display fossils or pictures of fossils
- modeling clay or playdough
- plaster of Paris
- old bowl and spoon
- modern day seashells
Key Vocabulary: fossils, brachiopods, sediments
- Pass around fossils to students. Ask students to describe fossils and to explain how they think fossils were formed. Inform students that they will make their own model of a fossil to better understand how they are formed.
- Give each student a lump of clay. Flatten the clay a little. This represents the mud on the bottom of the sea.
- Give each student a shell. Press it gently into the clay until a full impression is made. This represents an organism that has died and settled at the bottom of the sea.
- Carefully take the shell or rock out of the clay. This represents the organism turning to rock.
- Mix Plaster of Paris according to the directions. Spoon the plaster into the print in the clay. This represents the next layer of sediment and mud that covers the organism and print.
- When the plaster is dry, peel away the clay to reveal the fossil.
Extension: You can have the students paint the fossils if you choose.
Based on Carlsbad Caverns “Make a Fossil”