Iodine is used as an antiseptic treatment, but it can be poisonous if taken internally! Be sure that the solution is handled with care, and avoid all direct contact with the solution. At the conclusion of the experiment, place the bottle in the care of an adult and store out of the reach of children. Also, be sure to rinse your beaker and medicine droppers after each use noted in this exercise.
Step 1: Place a small amount of cornstarch (less than 1/8 of a teaspoon) in 15 mL of water. Using a medicine dropper, add one drop (or two if needed) of the iodine [NOTE: avoid direct contact with the iodine solution] to the cornstarch and water, and note the appearance of a bluish-purple color.
Step 2: Place the same amount of cornstarch in 15 mL of fresh orange juice. Using a clean medicine dropper, carefully add the iodine solution drop wise, stirring after each addition of a drop, until you see approximately the same change as noted in Step 1. Record the number of drops required for this change.
Step 3: Repeat Step 2 but use bottled green tea soft drink with an added anti-oxidant.
Step 4: Carefully cut a slice of fresh green pepper with a mass of approximately 20 grams. Cut the slice into smaller divisions in a sturdy container, add 15 mL of water, and mash the green pepper bits to extract any anti-oxidants. Let the mixture stand for approximately 15 minutes, then pour 15 mL of the solution into a beaker that contains about the same amount of cornstarch used in the previous steps.
Step 5: Carefully add drops of the iodine solution, stirring after every drop, until the appearance of the bluish-purple color in the solution.