Sizzling Sunset by Bryce Hixson
Calcium chloride is added to water in a plastic bag. As the chemical splits apart, it releases a noticeable amount of heat. An acid-base indicator, cresol red, is then added to the baggie along with sodium bicarbonate. As the chemicals react with one another, a large amount of carbon dioxide gas is released, the indicator changes color from red to yellow and, if you are lucky, the bag will explode.