Make two chemical solutions and mix them together. Wait a few seconds, then wow! It will suddenly change colors. This is the famous iodine clock reaction in an easy-to-use kit. Change the concentrations or temperature and change the delay for the color change. Do the clock reaction with Eco-foam. Learn about solutions and rates of reaction (kinetics). Contains starch solution. sodium iodate, sodium sulfite, citric acid, sodium thiosulfate, eco-foam, spoons, small scoops, cups, rack, and instructions. Ages 9+ with adult supervision. The REGULAR KITS (singles) include enough materials for repeating each experiment two to three times. The larger CLASSROOM KITS contain five times the materials of the single kits, enough for a five STATION CLASSROOM SETUP that can be REPEATED APPROXIMATELY three TIMES.