Vomiting pumpkin can be made using either one of two recipies -
the simplest one is baking soda reaction with vinegar,but the more
spectacular is the elephant tooth paste. To make it glow in the dark,
the second recipe is combined with luminol oxidation by hydrogen
peroxide.

Ingredients and Materials

1. Hydrogen Peroxide (H₂O₂): A chemical compound often used as a disinfectant or bleaching agent. In this reaction, hydrogen peroxide acts as the source of oxygen.
2. Dish Soap: Helps to trap the oxygen gas that is released, forming bubbles and foam.
3. Food Coloring: Used to make the foam visually appealing but doesn’t affect the reaction.
4. Yeast: Contains an enzyme called catalase that speeds up the decomposition of hydrogen peroxide.
5. Warm Water: Activates the yeast, helping the enzyme catalase work more efficiently.

Step-by-Step Chemistry Explanation

Step 1: Adding Hydrogen Peroxide to the Bottle

• Hydrogen peroxide (H₂O₂) is unstable and naturally breaks down over time into water (H₂O) and oxygen gas (O₂), but this process is usually slow:

  $$2H_2{O}_2\to 2H_{2}O+O_2$$

• In this experiment, we speed up the breakdown of hydrogen peroxide by using a catalyst (the enzyme catalase from yeast).

Step 2: Adding Dish Soap

• The dish soap doesn't participate in the reaction but plays an important role in capturing the oxygen gas that is released. When the hydrogen peroxide decomposes into oxygen and water, the soap traps the oxygen in the form of bubbles, creating the foam.

Step 3: Adding Food Coloring

• The food coloring is purely for aesthetic purposes. When the foam is generated, the color is carried up with it, making it visually striking.

Step 4: Mixing Yeast and Warm Water

• Yeast contains the enzyme catalase, which acts as a catalyst for the decomposition of hydrogen peroxide. A catalyst speeds up a chemical reaction without being consumed in the process.
• Warm water helps to activate the yeast, making the catalase enzyme more effective at breaking down hydrogen peroxide.

Step 5: Pouring the Yeast Mixture into the Bottle

• When the yeast mixture is added to the bottle, the catalase enzyme rapidly breaks down the hydrogen peroxide into water and oxygen gas. This creates a large amount of oxygen in a very short time.

  The rapid production of oxygen gas causes:

  • The trapped oxygen to form bubbles in the dish soap, resulting in a large amount of foam.
  • The foam rises quickly due to the vigorous release of gas, creating the “elephant toothpaste” effect.

Key Chemical Reaction

The primary reaction taking place is the decomposition of hydrogen peroxide, catalyzed by the enzyme catalase:

$$2H_2{O}_2\stackrel{\text{Catalase}}{\to }2H_{2}O+O_2$$

• Catalase: The enzyme that lowers the activation energy required for hydrogen peroxide to decompose, causing it to happen much faster.