The starch/iodine reaction is useful in many situations. Legend has it that John Dillinger used the reaction to break out of prison. Dillinger stole a raw potato from the kitchen and carefully carved it into the shape of a handgun. Since potatoes contain high concentrations of starch, Dillinger realized that painting the potato gun with iodine would give it a realistic metallic blue-black color. Iodine was readily available from a first aid kit. Dillinger pointed his gun at a guard, who was fooled into surrendering his real gun. The potato gun was shoved into the now unconscious guard's holster, and Dillinger escaped.
Author: Fred Senese senese@antoine.frostburg.edu