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Though the directions say to mix the iodine into the cornstarch and observe the changes, we found that mixing actually ruins the result as the iodine is too small a quantity and is easily covered up by the great mass of cornstarch. **In order to see an immediate and apparent result (the yellow iodine drops will immediately turn black upon contact with the cornstarch), merely have your student note the color of the solution BEFORE placing a few drops onto a sample of cornstarch. As soon as the drops impact with the cornstarch, they will turn black. The drops may be flattened a little in order to increase the surface area with the cornstarch, but mixing will actually cause a messy, globular paste that will hide the iodine, concealing the result.

In order to get a chemical change, you need to greatly reduce the amount of corn starch used with the iodine (or obtain a lot more iodine than is included in the kit).