Feel the Heat 

Ingredients:

• Test Tube with stopper
• 1 teaspoon of quick-rising dry yeast (from the grocery store)
• 1 tablespoon hydrogen peroxide (be careful with this—get an adult to help)

What to do:

• Pour the hydrogen peroxide in the test tube, and feel the temperature on the test tube
• Add the yeast, put the cap on and shake thoroughly
• Watch what happens, and feel the lower sides and bottom of the test tube.
• Pour some liquid into your hands to feel the heat

What happened?

You've just seen an exothermic chemical reaction! When the yeast is mixed with the hydrogen peroxide, the molecules of the hydrogen peroxide change into oxygen and water. That change produces heat, and that's what exothermic means–a process that produces heat. The extra oxygen bubbles that were separated escape in the form of bubbles.