These rugged clear plastic molds can be filled with plaster of paris, clay, sand, soap, paper mache, chocolate, jello, or food. Students can taste science now or just create fun food items that are sure to get comments. With the clays and paper casts, children can dry them and paint unique designs on the casts. Great fun for the classroom, nature center, or home. Average size of mold is 3 inches in diameter.