Science Experiment - Elephant Toothpaste For Summer

Elephant Toothpaste is a fun science experiment to see the physical foamy effect of a chemical reaction. There is enough foam squirting out for an elephant to brush its teeth. Maybe elephants don’t like brushing their teeth because this toothpaste doesn’t taste good to humans or animals.

It takes less than 30 minutes to conduct the experiment and clean up afterward.

Supplies Needed

Supplies for Kids-safe version

  • 1-liter Plastic soda bottle
  • Decorative wrap that looks like a tube of toothpaste
  • Safety goggles and rubber gloves for each kid
  • Plastic tarp to cover the working surface
  • Funnel
  • 4 ounces of 10-volume or 20-volume hydrogen peroxide (3% or 6% hydrogen peroxide). Peroxide used for bleaching hair is 6% and 3% is normally found in the medicine cabinet.
  • Liquid dishwashing soap
  • 8 Drops of food coloring
  • Dry yeast 1 packet or 1 tablespoon
  • Small plastic cup
  • 4 Tablespoons very warm water (105-110 degrees F)
  • Measuring cups and spoons
  • Tray
  • Spoon

Supplies for Lab version

  • Safety goggles, gloves, and lab coat to protect clothes, skin, and eyes from burning if hydrogen peroxide is accidentally spilled.
  • 30% Hydrogen peroxide
  • A saturated solution of potassium iodide (K)
  • Liquid detergent
  • Graduated cylinder
  • Food coloring

Supplies for Variations

  • Use different shaped bottles. Short bottles and bottles with narrow necks have better results. Wide based bottles are more stable and won’t easily topple over.
  • Add plastic glitter not metal glitter or sparkles
  • For a fountain, cascade effect, use a soda bottle and 3% hydrogen peroxide
  • Different colors of food coloring to make a striped effect.
foam explosion of elephant toothpaste
Passavitch [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]

What Mystery Are We Solving?

What causes the creation of lots of foam when hydrogen peroxide, soap, and a catalyst are mixed together?

Why are the foam and container hot to the touch?

Safety Issues

DON’T EAT This. It tastes awful and isn’t safe to eat.

Wear safety goggles and gloves during the experiment and when cleaning up. Avoid spilling the hydrogen peroxide when mixing. If the child is too young, don’t let them handle the hydrogen peroxide. They can add the dish soap and food coloring to the peroxide. If accidentally spilled on the skin wash it immediately off with soap and water.

The kid-safe version of the experiment isn’t dangerous. Have an adult present to help and use common sense. After the experiment, the items can be thrown into the dustbin or washed down the sink. Glitter should be strained before the liquid is washed down the sink. Clean immediately because yeast can smell bad when left.

The iodide is yellow in color and may stain skin and clothes. It’s best to cover skin and clothes during the experiment. Conduct the experiment on a washable stain-resistant surface (or place a plastic tarp on the surface and possible spill area).

The reaction happens quickly. Make sure kids stand away from the bottle or cylinder after the catalyst is added.

Wait for the foam to cool before touching it. The energy released may cause too much heat for immediate touch.

How To/Directions

Kids-safe Version of Elephant Toothpaste

  1. Make a decorative wrap for the plastic bottle that it looks like a tube of toothpaste. Cover the bottle with the wrap.
  2. Cover the table or working surface with a plastic tarp.
  3. Place the tray on the plastic tarp and the bottle on the tray. The tray contains the foam to a certain degree.
  4. Put on safety goggles and gloves.
  5. Place the funnel in the mouth of the soda bottle.
    1. Pour 4 ounces of 40-volume hydrogen peroxide into the soda bottle.
    2. Add a squirt of dish soap.
    3. Add some food coloring.
    4. Mix the contents by lightly swirling the bottle.
    5. Place back on the work surface.
  6. Make the catalyst with the yeast.
    1. Take the plastic cup.
    2. Mix the package of dry yeast with 4 tablespoons of warm water.
    3. Stir with the spoon.
    4. Dilute with warm water if the mixture is too thick.
  7. Pour the yeast mixture into the plastic soda bottle.
  8. Wait a few seconds for the reaction.

Lab Version of Elephant Toothpaste

  1. Wear goggles, gloves and lab coat for protection.
  2. Place the graduated cylinder on a stable surface and add the hydrogen peroxide.
  3. For striped toothpaste add food coloring drops by tilting the cylinder and dripping the coloring down the sides of the graduated cylinder. Don’t mix the colors.
  4. Add 2 ½ Tablespoons of powder dish soap or pour liquid dish soap down the side. Swirl to mix thoroughly.
  5. Add potassium iodide with a spatula. and stand back immediately.

What Just Happened Here?

Hydrogen peroxide’s chemical formula is H2O2. Without the catalyst, the hydrogen peroxide molecules may break apart without a visible effect. The molecule separates into two liquid H2O (water) molecules and one O2 (oxygen) gas molecule. The breaking apart of the molecule is called a decomposition reaction.

The catalase enzyme in the yeast works as a catalyst. It speeds up the reaction without changing the product. Therefore, the oxygen gas and water molecules are rapidly released as the H2O2 molecule decomposes.  

The soap detergent binds and traps the oxygen gas molecule in a bubbly foam. The oxygen gas forms the foam and bubbles that rise to the surface creating the toothpaste effect.

The less concentrated the hydrogen peroxide, the more catalyst is required for a reaction.

The bottle and foam are hot to the touch because of the exothermic reaction.

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