Recently I wrote a post for the Jacksonville Moms Blog highlighting some of my favorite science experiments for big kids. These were all done for the Mad Science Party we threw for Cole's 8th birthday. Here are the details for the Elephant Toothpaste Experiment.
Materials: Clean & empty soda or water bottle, Yeast, Warm Water, Food Coloring, Dish Soap, 6% Hydrogen Peroxide (you can find this online or at a beauty supply shop)
Directions: In a separate cup mix 1 teaspoon of yeast with 2 tablespoons of warm water. In your soda bottle mix together ½ cup of hydrogen peroxide, a squirt of dish soap and a few drops of food coloring. Swirl the soda bottle to mix slightly. Pour the contents of your yeast & water mixture into the soda bottle and watch your elephant toothpaste erupt.
Why it works: Hydrogen peroxide naturally breaks down into water and oxygen. It is stored in opaque containers to help slow down this process. Yeast speeds up the reaction. Dish soap catches the oxygen and makes bigger bubbles and the food coloring makes it look cool. The foam and bottle feel warm because the reaction is exothermic–it releases energy as heat.