1. They used fresh lemon juice to write a secret message on white paper. They observed how the paper and message changed when heat was added.
2. They observed the properties of a bar of soap then predicted what would occur when heat was added.
3. They observed milk that had 1 1/2 table spoons of white vinegar and fresh lemon juice added. Then predicted what would happen when heat was added and then when heat was taken away ( milk cooled).