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Elephant Toothpaste

Elephant Toothpaste Description

Objective

Understand exothermic reactions and catalysis. Understanding chemical v. physical change

Key Components of the Chemical Change:

Decomposition of Hydrogen Peroxide: Hydrogen peroxide naturally breaks down into water and oxygen over time, but this process is very slow. The catalyst (potassium iodide or yeast) speeds up this decomposition significantly.

Formation of New Substances: The clear indicators of a chemical change include the formation of new substances (water and oxygen gas in this case) and the release of energy in the form of heat.

Observable Effects: The rapid release of oxygen gas creates foam, made up of tiny bubbles of oxygen trapped in a liquid. Soap added to the reaction mixture captures the oxygen, creating a mass of frothy foam that looks like toothpaste big enough for an elephant, hence the name. The heat released can be felt by touching the sides of the container after the reaction.

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H2O2 is Peroxide, H2O is water and O2 is oxygen. The yeast is not represented because it is not consumed in the reaction, it only speeds it up.

Elephant Toothpaste Instructions

Safety Precautions

Wear safety goggles and gloves.

Conduct the experiment in a well-ventilated area or outdoors.

Adult supervision required, especially with higher concentrations of hydrogen peroxide.

Instructions

Preparation

Wear safety gear: Put on goggles and gloves.

Container setup: Place the tall container on a tray. Add food coloring to the sides if desired.

Catalyst Preparation

Yeast mixture: Dissolve 1 tablespoon of yeast in 3 tablespoons of warm water. Stir for 30 seconds. (Skip this step if using KI.)

Experiment Setup

Hydrogen peroxide: Pour 1/2 cup into the container.

Add dish soap: Mix in about 1 tablespoon of liquid dish soap.

Activate reaction: Quickly add the yeast mixture (or KI) to the container.

Stir: Mix thoroughly with a stick or spoon.

Observe: Watch the rapid foam formation and note the warmth indicating an exothermic reaction.

Clean-up and Disposal

Neutralize: The reaction products (water, oxygen, soap) are safe for drain disposal.

Hydrogen peroxide: Dispose of or store remaining hydrogen peroxide according to local regulations.

Discussion Points

Discuss the chemical reaction, the role of catalysts, and the concept of exothermic reactions.

Materials

Hydrogen Peroxide Solution (6% or higher concentration)

Large pan

Active Dry Yeast or Potassium Iodide (KI)

Warm Water

Liquid Dish Soap

Food Coloring (optional)

Safety Goggles and Gloves

A Large, Tall Container

Measuring Spoons and Cup

Stirring Stick or Spoon