Use a bottle of hand sanitizer to teach the concept of evaporation to preschool students. Sanitizer works because of crenation, the removal of water from a cell. The alcohol dries out the cells of microbes, destroying the germs. Pour some sanitizer into a student's hands. Have him rub his hands together. As his hands quickly transition from wet to dry, explain the concept of evaporation.
For elementary school students, use bowls or glasses of water to teach evaporation. Have your students fill their cups or bowls with water and mark the water level on the outside of the container. Each day, have them mark the new water level. Continue this for several days and then ask your students about what they believe is happening to the water. Have them describe their personal observations of evaporation in nature.
Middle school students likely know about evaporation. They may not know how various environmental factors can affect the process. Home Science Tools recommends an experiment that analyzes the effect of temperature on evaporation. Have students poor equal volumes of water over two identical sponges. Direct the light of a lamp or another heat source onto one sponge and place the other sponge in the shade. Ask students to predict the result of the experiment. After several hours, squeeze the water from each sponge and record the volume. Discuss the results.
High school students are ready to learn advanced concepts such as the Mpemba effect, which theorizes that hot water freezes more quickly than cold water. Scientists hypothesize that evaporation plays some role in the Mpemba effect, as hot water evaporates faster and takes heat with it, resulting in less remaining water to freeze. To demonstrate the concept, students can experiment freezing water starting with a different water temperature each time. Your students should track the freezing time for each experiment and discuss possible outcomes.