Science Projects
Starch Test

Items needed:
	Tincture of iodine (from the pharmacy)
	Paper
	A Dollar Bill
	Toothpick
	Bread or a Cracker

Warning! Iodine is poisonous and will stain skin and clothing. Also, some people are allergic to iodine. Be safe and careful.

Usually the bottle of iodine has a plastic stick attached to the cap, to make it easy to apply. Use this or a toothpick to put a tiny bit of iodine on a piece of white paper. Notice that the paper turns black. Put a drop of iodine on a piece of bread or cracker and it will also turn black. This is an indicator test. Iodine turns black when it comes in contact with starch. Most paper contains starch and will turn black with iodine. Now put a drop of iodine on a dollar bill. It stays a brownish color.

Why? Iodine turns black when it comes in contact with starch. Most paper contains starch and will turn black with iodine. The special paper used from printing U.S. money does not contain starch, which is one of way that you can spot a counterfeit bill.

Try testing small pieces of different fruits and vegetables, to see which ones contain starch. Be sure to throw away the things you test, to be sure that no one accidentally eats any of the iodine. You might also try testing different kinds of paper, to see if you can find any others that are starch-free. Any of you that are outside the U.S., let me know if the bills from other countries are starch-free too.

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