Elephant Toothpaste

Concept: Exothermic Reaction
An exothermic reaction is a chemical reaction that releases energy in the form of heat. It is the opposite of an endothermic reaction. The easiest way to understand the differences between exothermic and endothermic reactions is from the meaning of their names. “Exo” means “to give off” and “Endo” means “to draw into.” Exothermic reactions give off heat to their surroundings and endothermic reactions draw heat in from their surroundings. 

Read Aloud: Fire Bubbles and Exploding Toothpaste by Steve Spangler

Ingredients:

      ·         1 cup Hydrogen Peroxide (20-Volume/6% Solution)

      ·         1 tbl. Liquid Dish Soap

      ·         2 tbl. Water (Warm)

      ·         1 tsp. Dry Yeast

      ·         Food Coloring

      ·         Plastic Bottle

      ·         Plastic Cup

      ·         Funnel

Demonstration:

      ·         Pour ½ cup of hydrogen peroxide into the plastic bottle.

      ·         Add 4-8 drops of food coloring to the plastic bottle.

      ·         Pour 1 tablespoon of liquid dish soap into the plastic bottle.

      ·         In a plastic cup, combine 2 tablespoons of warm water and 1 teaspoon of dry yeast and stir for 30 seconds.

      ·         Pour the mixture into the plastic bottle quickly using a funnel.

Experiment:

·         Does the size of the bottle affect the amount of foam produced?

·         Does changing amount of yeast used change the amount of foam produced?

Observations:

Each tiny bubble in the foam is filled with oxygen. The yeast acts as a catalyst to remove the oxygen from the hydrogen peroxide. Since it did this very quickly, it created lots of bubbles as well as released energy in the form of heat.