How do you know if certain substances contain starch? Starch, a substance found in plants, gives us energy (sugars and fats do, too!). Chemists are especially interested in starch because it is a compound made up of carbon, hydrogen and oxygen. This experiment will help us find out if a solution has starch.
Things Required:
Half-litre plastic bottle or similar container, 3/4 filled with water
2 teaspoonfuls of cornstarch
A spoon (a disposable plastic one is best)
Medicine dropper
20 drops of Tincture of Iodine
Directions:
Spoon the cornstarch into the bottle of water. Add the drops of iodine to the water. Swirl the contents around and then let the solution “rest” for a few minutes.
This Is What Happens:
The water turns dark blue or purple.
Science Behind It:
Iodine is a good test for starch. It combines chemically with starch, in this case cornstarch, to produce the dark blue colour. Chemists regularly use iodine for this purpose.
