This experiment teaches students about solubility. Dissolve 100 grams of cupric sulfate in 200 grams of water over a hot water bath. Cool the solution overnight. During the next class period, examine the crystals that should have formed in the beaker. The crystal formation is due to supersaturation, and weighing the crystals will help students learn about experimental yield. For a more advanced project, have students place the beakers in different locations overnight, such as a refrigerator, an oven or a warm room. Examine how the amount of crystallization differs based on the location.
Decomposing cupric sulfate teaches students about the chemical property of structure, as well as the physical property of color. Using a hot plate, heat the cupric sulfate to 63 degrees Celsius. At this temperature, the chemical loses two water molecules. It loses two more when it is heated to 109 degrees Celsius. By this stage, the chemical will have changed from blue to white. This is due to the change in molecular structure after the water molecules have been removed.
Begin with decomposed cupric sulfate that has been heated until it has turned white. Add water and the chemical will return to its original blue color. This is due to mineral hydration, the process in which water is added to a salt. By adding water, the chemical returns to its pentahydrate form, which appears blue. By performing this experiment, students learn more about hydration, which is the "opposite" experiment to decomposition, where water is added instead of removed from the structure.
Take a loose bundle of steel wool and leave it in a beaker of dissolved copper sulfate for an hour. The steel wool will lose its silver color and become a copper color. This reaction is a single replacement reaction: the iron from the steel wool "swaps" with the copper from the cupric sulfate, creating iron sulfate and dissolved copper. The longer this solution sits, the more pronounced the color change will become.