Hooked on Science: Elephant's toothpaste

Materials

• 16-ounce plastic soda bottle
• 20-volume hydrogen peroxide
• Dry yeast
• Warm water
• Dishwashing liquid

Instructions

STEP 1: Pour half a cup of 20-volume hydrogen peroxide into the 16-ounce plastic soda bottle.

STEP 2: Add 1 teaspoon of dishwashing liquid.

STEP 3: Mix 3 tablespoons of warm water with 1 tablespoon of dry yeast.

STEP 4: Pour the warm water and dry yeast into the bottle and observe.

Explanation

The yeast acts as a catalyst, quickly removing the oxygen from the hydrogen peroxide, creating a lot of bubbles. The bottle warms up because of an exothermic reaction, which is a reaction that releases heat.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website, hookedonscience.org, for webcasts and experiments.