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    Clearly it's Vitamin C

    Kids, which has more vitamin C in it: Tang® drink mix or orange juice? Let’s use some chemistry and a color test to find out. Have an adult make an iodine solution by adding 1 teaspoon of tincture of iodine to 1 tablespoon of water in a labeled plastic cup.

    Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

    Use two 8-oz plastic cups to make a starch solution: dissolve the 4 starch pellets (biodegradable packing peanuts available at mailing supply stores) in 1/2 cup of water. Cover the other cup with a coffee filter in an indented bowl-like shape. Pour the starch solution through the filter and label this clear solution as “Starch”. Label three 3-oz plastic cups as “Vitamin C Test”, “Tang Test”, and “Orange Juice Test”, and put 1 tablespoon of starch solution in each. Now add 1 drop of the iodine solution to each test cup using an eyedropper. What happens? They should all turn blue from the starch/iodine complex that forms.

    Label a fourth cup “Vitamin C Solution”. Crush up a vitamin C tablet, put it in the cup, and add 2 tablespoons of water with stirring. Now place 1 drop of this vitamin C solution in its test cup (“Vitamin C Test”) and swirl. What happens? (If nothing happens add another drop). Next mix 3/4 teaspoon of Tang® powder in 2 tablespoons of water in the fifth cup and label it “Tang Drink”. Put a drop of this drink in the Tang Test cup. Does it take more drops to turn the solution clear than vitamin C? Lastly, add 1 drop of orange juice to its test cup. Does anything happen? How many drops of orange juice does it take for this solution to become clear?

    So which has more vitamin C in it, Tang® or orange juice? The more vitamin C a solution has, the fewer drops it takes to turn the starch/iodine solution clear. So the fewer drops it takes, the more vitamin C the solution has. Try testing some other drinks for vitamin C, such as calcium-fortified orange juice, orange soda, lemon-lime soda, cranberry juice, or anything that says “ascorbic acid” (another way of saying vitamin C) in the list of ingredients.

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    Kathleen Carrado Gregar, PhD, Argonne National Labs 
    [email protected]
    October 1999

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    Reference: “WonderScience” from the American Chemical Society, 1999, vol. 13(6), issue on chemistry & color (ACS, 1155 Sixteenth St., N.W., Washington, DC 20036).

    P.S. The tablet should have the most vitamin C, followed by Tang, and lastly the orange juice (which has the least).