Elephant toothpaste

This morning I received an email from the science museum that contained some great experiments. Today was a free day for us so I thought it would be great fun to try an experiment or two.

One in particular, I remembered from high school. It ALWAYS got such a great response from the students. It's quick, messy, silly and fun. Sounds perfect for 4 year olds as well! So after breakfast, the kids and I gathered our materials to make ELEPHANT TOOTHPASTE!

Here is our preschool Elephant Toothpaste!

And yes, my kids are wearing their protective eyewear on their foreheads. You know, just in case something gets on their forehead... 

As evidenced by their giggles and squeals of delight, they loved this.

If you want to try this at home, here are the instructions we had and the preschool version of the explanation of what is happening. 

Original video with instructions: http://www.youtube.com/watch?v=7MAHi33yHt4
Here are the written instructions:

1. Put on old shirt and safety goggles
2. Place an empty 16oz plastic bottle upright in a foil cake pan with 2 inch sides (we just used the kitchen sink) with a funnel on top.
3. Mix 2TB warm water with 1ts yeast.
4. Pour 1/2 cup hydrogen peroxide into the funnel and add a couple drops of food coloring.
5. Add a few drops of dish detergent.
6. Add the yeast / water mixture to the bottle and remove the funnel quickly.

And there you have elephant toothpaste! And very giggly kids!
For an explanation of the science:

• Hydrogen peroxide may look like water, but it has an extra Oxygen. This makes it a powerful oxidizer. The yeast acts as a catalyst, speeding up the reaction when the hydrogen peroxide is decomposed. Hydrogen peroxide breaks down to form water and oxygen. The erupting soap bubbles are filled with this oxygen. If you look closely, you may see steam coming out of the bottle! This results because the reaction is exothermic, meaning it gives off heat.

Translation for Kyle and Emily:

• Feel the bottle. It's warm isn't it? When an experiment like this has a reaction that makes it warm, it's called exothermic.
• And the toothpaste - it's the soap being filled with air. The air comes from the hydrogen peroxide reacting with the yeast. The yeast makes it break down to be water and air. And when the air gets in the soap, it bubbles up.