Extreme Science: Penny Shine

What you will need:

  • Safety glasses
  • Small glass or containers
  • Iodine (Potassium iodide)
  • Dropper
  • Liquid Starch
  • Water
  • Bleach (optional)
  • Adult supervision


NOTE: Make sure that you have adult supervision for this experiment AND wear your safety glasses!

Add 1 teaspoon of liquid starch to 2/3 cup of water in a small glass or container. In another small container, pour in ¼ cup of water and carefully add about 10 drops of iodine. Slowly pour the water (containing the iodine) into the glass of water (containing the liquid starch) It should turn a deep purple color.

What is going on?

You just caused a chemical reaction! There are three basic indicators of a chemical reaction. When a chemical reaction takes place, one or more of these indicators will be present.

1. Change in temperature

2. Gas or odor is produced

3. Change in color

Whenever starch and iodine are mixed together, the chemical reaction that is taking place will produce a purple color. Because of this, we can use iodine to test for the presence of starch as well as using starch to test for the presence of iodine

Try this:

Try adding about ¼ cup of liquid bleach to the “purple” mixture. What happens? Is there another chemical reaction taking place? Why or why not? How can you tell?

Radical Rick

Extreme Science