Discuss with the students that when you change Butyl Stearate to a solid and back again, do you change the substance itself. Does water change when it goes from a liquid to a solid and back again. The two substances have different rates for changes because they change at different temperatures. Students could make jello. Students observe and infer what happens when matter interacts.
Students observe and record changes of gobstoppers in water.
Resources Full Option Science System-Solids and Liquids . Lawrence Hall of Science, Berkeley, California. Great Explorations in Math and Science. Liquid Explorations . The Regents of the University of California, 1987.