Foamy Chemistry – The Elephant Toothpaste Challenge

The Mission:

You are a chemical engineer optimizing a reaction. You will run three trials to determine which variable creates the tallest and widest foam explosion: the temperature of the catalyst (yeast) or the concentration of the fuel (hydrogen peroxide).

Safety First:

• Goggles ON at all times.

• Pour hydrogen peroxide quickly and pull back fast. The reaction starts immediately!

• Do not touch the foam right away (it produces heat).

Materials Per Group

• Safety Goggles

• 1 Plastic Bottle (Reusable)

• Large Tray or Tub (to catch the mess)

• Ruler

• Liquid Dish Soap

• 3 Packets of Dry Yeast

• Hydrogen Peroxide: 3% (Standard) and 6% (High Strength)

• Water: Cold and Warm (from Electric Kettle)

The Protocol

Follow these steps for every trial. Rinse your bottle thoroughly between tests!

1. Load the Catalyst: Add 1 packet of yeast and 3 tbsp of water (see trial list below for temp) directly into the bottle. Swirl for about 2 minutes to mix.

2. Add Soap: Add a squirt of dish soap to the bottle.

3. *Optional* Add food coloring

4. The Reaction: Quickly pour 1/2 cup of Hydrogen Peroxide into the bottle and step back!

5. Measure and Record:

   • Height: Use the ruler to estimate how high the foam shot up.

   • Spread: Measure the width of the foam pile in the tray.

Your Experiments

Trial 1: The Cold Standard

• Water: Cold

• Hydrogen Peroxide: 3%

• Observation: Measure height and spread. Rinse bottle.

Trial 2: The Heat Check

• Water: Warm

• Hydrogen Peroxide: 3%

• Observation: Compare to Trial 1. Did heat speed it up? Rinse bottle.

Trial 3: The Power Boost

• Water: You decide! (Based on previous results, which temp works best?)

• Hydrogen Peroxide: 6%

• Observation: How did the higher concentration change the explosion compared to the 3% trials?

Analyze & Discuss

• Data Comparison: Which trial had the greatest height? Which had the widest spread?

• Variables: Which had a bigger impact on the reaction: warm water or stronger Hydrogen Peroxide?

• Exothermic Reaction: Carefully hover your hand near the foam (do not touch). Do you feel heat? The energy released is evidence of a chemical change.

The Science Behind the Foam

Now that you have your data, watch this breakdown of what happened at the molecular level.