Iodine Rainbow

This is the experiment that your audience will remember from your chemistry magic show. Here's what happens - you call up six 'helpers' and hand each a seemingly empty test tube. Into each test tube, pour a little of the main gold-colored solution, say a few magic words, and their test tubes turn clear, black, pink, gold, yellow, and white. With a flourish, ask them to all pour their solutions back into yours and the final solution turns from inky black to clear. Voila!

I first saw a similar experiment when I was a kid, and I remembered it all the way through college, where I asked my professor how I could duplicate the experiment on my own. I was told that the chemicals used in that particular experiment were way too dangerous, and no substitute experiment was possible, especially for the color reversal at the end. I was determined to figure out an alternative. After two weeks of nothing but chemistry and experiment testing, I finally nailed it - and the best part is, you have most of these chemicals at the grocery store. (And the best part is, I can share it with you as I've eliminated the nasty chemicals so you don't have to worry about losing an eyeball or a finger.)

NOTE: This experiment requires adult help, as it uses chemicals that are toxic if randomly mixed together.  Follow the instructions carefully, and do not mix random chemicals together.

Are you ready to mix up your own rainbow?

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Materials:

• Iodine (non-clear, non-ammonia from the pharmacy)
• Hydrogen peroxide (3% solution)
• Vinegar (distilled white is best)
• Cornstarch (tiny pinch) or one starch packing peanut
• Water (distilled)
• Sodium Thiosulfate
• Sodium Carbonate (AKA: "washing soda")
• Phenolphthalein (keep this out of reach of kids) - this is optional
• Disposable plastic cups (about eight)
• Popsicle sticks
• Gloves for your hands
• Goggles for your face
• Medicine droppers (at least four)

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