Click a thumbnail picture below to view a larger version.

View Movie

Narrative
A solution of malonic acid, starch indicator, and manganese(II) catalyst is added to a solution of hydrogen peroxide, iodate, and sulfuric acid. The electrical potential of the solution is monitored with a platinum electrode attached to a strip chart recorder. Each color change is accompanied by a change in voltage. As the reaction proceeds, the time between color and voltage changes increases. Eventually the color oscillations will no longer be observed, and the voltage oscillations will become very small. The generation of iodine, however, will continue until one of the reactants is used up.