Use the classic density demonstration of placing a cola, a clear soda, and a diet soda into a tank of water. Then let learners attempt to pour some of the soda into layers in a clear container. The procedure explains a thermocline, and asks them to come up with a term that describes the reason for stratification in this situation. Students measure the layers and the transition zone between them. This is an impressive activity that can be used in environmental science or chemistry. Note, however, that the formatting isn't quite as impressive.