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Christmas Tree Elephant Toothpaste Chemistry Demonstration

Easy Christmas Tree Demonstration

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The elephant toothpaste demo is an exothermic chemical reaction.

The elephant toothpaste Christmas tree is one of the chemistry demonstrations featured at the Chicago Museum of Science and Industry live show.

Anne Helmenstine at the Chicago Museum of Science and Industry
Did you know you can do the elephant toothpaste demonstration to make a Christmas tree holiday chemistry demonstration? It's extremely easy, plus it makes an excellent demo to do before the holiday break!

Safety Information

Hydrogen peroxide is an oxidizer. This demonstration uses a higher concentration of hydrogen peroxide than the home variety, which means you need to wear gloves to protect your hands against an accidental splash or spill, which could cause a burn.

Christmas Tree Elephant Toothpaste Materials

There are a few ways to set this up to make a Christmas tree. The key is to add green food coloring to get the tree effect and then either perform the demonstration in an erlenmeyer flask, which naturally produces the tree shape, or else perform the reaction in a tube with a tree template placed over it. You can make a tree shape from aluminum foil, with slots cut up the side and an opening at the top to force the foam from the reaction out into the proper shape.
  • 50 ml of detergent
  • 100 ml of 30% hydrogen peroxide
  • 10 ml of a saturated solution of potassium iodide
  • green food coloring
  • erlenmeyer flask or homemade Christmas tree model

Procedure

  1. Place the erlenmeyer or your Christmas tree container on the lab bench. Add the detergent, peroxide and food coloring.

  2. Pour the potassium iodide solution into this mixture to catalyze the reaction.

  3. Optionally, touch a glowing splint to the foam "tree" to relight the splint and demonstrate that the bubbles are filled with oxygen.

Chemistry

Hydrogen peroxide is catalytically decomposed into water and oxgen. This is a nice example of an exothermic reaction. The audience will be able to see steam rising from the foam.

The overall equation for the elephant toothpaste chemical reaction is:

2 H2O2(aq) → 2 H2O(l) + O2(g)

The decomposition reaction of the hydrogen peroxide into water and oxygen is catalzyed by the iodide ion.

H2O2(aq) + I-(aq) → OI-(aq) + H2O(l)

H2O2(aq) + OI-(aq) → I-(aq) + H2O(l) + O2(g)

Dishwashing detergent is added to capture the oxygen and form bubbles. This is an exothermic reaction which may produce steam.

Kid-Friendly Version of the Demonstration

If you can't obtain 30% hydrogen peroxide or simply want a demonstration that is safe enough for kids to perform, you can perform an easy variation of this demonstration:
  • detergent
  • warm water
  • 3% hydrogen peroxide (the type sold at pharmacies)
  • pack of active yeast (from a grocery store)
  • green food coloring
  1. In an erlenmeyer or tree-shaped container, mix together 1/4 cup detergent, 1/2 cup of the 3% hydrogen peroxide and several drops of green food coloring.

  2. In a separate container, stir the packet of yeast into a small amount of warm water. Allow 5 minutes for the yeast to activate before proceeding with the demonstration.

  3. Perform the demonstration by pouring the yeast mixture into the peroxide and detergent mixture.
This reaction does not produce the huge volume of foam of the traditional elephant toothpaste reaction, but all of the chemicals are safe enough for kids to handle. In this reaction, yeast catalyzes the decomposition of hydrogen peroxide into water and oxygen gas:

2H2O2 → 2H2O + O2(g)

As in the other reaction, the detergent captures the oxygen to form bubbles. Less foam is produced because there is a smaller amount of hydrogen peroxide to decompose.

Learn More

Red and Green Color Change Christmas Demonstration
Elephant Toothpaste Variations
Borax Crystal Snowflake Decoration

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