This is really fun for students that are learning about fossils and imprints.1. I found some inexpensive plastic dinosaurs skeletons at Oriental Trading Company, which are perfect for this project. I used regular clay for the imprints, play dough would work also.
2. To prepare for the plaster pouring, give each student a 5" square of cardboard, an 11" x 2" strip of heavy weight paper, a bit of tape, and the 2.5" ball of clay. The students are to tape their strip of paper into a ring, overlapping about an inch. With the paper ring laying on the cardboard, they should make their ball into a flat "pancake" that will fit inside the circle.
3. With the "pancake" removed from the paper ring, the student is to take a dino and make an impression into the clay, using the side of the head. If there is room, a foot print may be added. Make sure they make a firm imprint.
4. The "pancake" gets placed back in the paper ring, impression side up. Plaster is mixed with water until it is the consistency of pudding, and then poured into the ring. Pour enough plaster to make a layer that is about 1" thick.
5. After the plaster has dried (about an hour) the paper ring can be torn away and the dough can be removed. If it sticks to the plaster, let it dry 24 hours and then scrub with a brush under water.
6. After the plaster fossils are clean and dry, paint them with very watered-down paint. Watercolor or tempera work, anything to give the plaster a muddy look.
My son loved making this model in the 2nd grade.
