Demo-Elephant+Toothpaste-Daniel+Rodriguez

Elephant Toothpaste
This experiment is pretty amazing to watch, although the Chemistry behind it is very simple. It is called "elephant toothpaste" because it supposedly producesthe same amount of foam that an elephant would use to "brush its teeth".

Materials List:
 * 125 mL of KI (Potassium Iodide)
 * 200 mL of H2O2 (Hydrogen Peroxide) (30%)
 * 50 mL of Dish Soap
 * Some drops of food coloring (just to make it look nicer)

Here is a video of how the reaction goes: []

The Chemistry behind this experiment is as follows:

1. First, the hydrogen peroxide decomposes when as it reacts with the iodine anions that the potassium iodide releases, forming a compound with oxygen and releasing some water H2O2 (aq) + I-(aq)  OI-(aq) + H2O(l)

2. Then, the compound with oxygen and iodine (OI) will react with the hydrogen peroxide that has not been involved in the reaction yet, which yields iodine ions, water and oxygen. H2O2 (aq) + OI-(aq) I-(aq) + H2O(l) + O 2(g)

3. Finally this is the overall reaction which is just a decomposition of hydrogen peroxide into water and oxygen under the effects of the potassium iodide, which at the end stays out of the reaction. Since heat is produced, this reaction is an exothermic reaction. 2 H2O2 (aq)  2 H2O(l) + O 2(g)

4. What actually makes the foam go up so quickly is that the rate of this reaction is very fast and as water is produced, it mixes up with the dish soap and then as oxygen is produced, all the bubbles and foam start going up quickly.

Reference: Unniversity of Minnesota-Chemistry Department []