If you are looking for a “wow factor” outdoor science experiment for the kids this summer, you have come to the right place! Mixing together some reactive ingredients on the sidewalk creates this foamy, blast-y, feast for the eyes that resembles toothpaste that a big elephant could use!
You will need:
- An empty, rinsed clean, 2 liter plastic bottle
- Food coloring of your choice (red, purple, green, blue)
- 4 ounces of hydrogen peroxide, 40 volume (available online)
- Very warm water
- 1 packet of dry yeast
- Dish soap
- Safety goggles and gloves
Next, let’s talk safety. This experiment uses 40 volume hydrogen peroxide. It is the same type of solution that can make dark hair blonde in a salon. It is a higher concentration than what is available in the drug store, and is easily available for about $10 online. Be sure to purchase the clear version, not the cream, otherwise this experiment will not work. It will absolutely irritate or even burn the skin, so adults with gloves should only handle the hydrogen peroxide.
This is an EYES ONLY experiment. Do not touch the foam when it comes out. Why? Because of the chemical reaction it will be HOT! Let it cool and have an adult clean it up. (Another great reason to take it to the cement patio or sidewalk…you can easily hose or water down these areas).
Let’s get started!
First, place your clear bottle on the cement patio, sidewalk, parking lot, or driveway. You’ll want it in a spot that is easy to clean with a hose or pitcher of water.
Add a few squirts of dish soap to the bottom of the bottle.
ADULTS ONLY: With gloves on, measure out four ounces of the 40 volume hydrogen peroxide.
Using the funnel, carefully pour into the bottom of the bottle. Swirl together.
Empty the yeast packet into 4 ounces of warm water. Stir to dissolve the yeast. In order for the yeast to react, very warm water is in order. Because we handled this experiment outdoors, we boiled water and then brought it outside with us during set up. The water remained warm enough for the yeast to dissolve.
Next, drip the food coloring down the sides of the bottle. This will give the “toothpaste” its stripes, similar to what your child sees in their bathroom cabinet.
ADULTS ONLY: Using the funnel, pour the liquid yeast into the liter bottle. Remove the funnel and stand back.
Look at that foam fly!
It was so much fun, we did it again – and changed up the colors!
Check out Elephant Toothpaste in action!
What makes elephant toothpaste?
There are two important words to know to understand this experiment:
- Catalyst – an element that speeds up a reaction
- Exothermic – the act of releasing heat
Hydrogen peroxide, believe it or not, is very similar to water. It has one additional oxygen atom. When you add active yeast to hydrogen peroxide, it will act as a catalyst, releasing oxygen quickly. From the oxygen and water that is left behind from that first reaction, the dish soap will trap that oxygen. The result is the foam you see. The bottle is hot because the reaction is exothermic.
Now go have some summer science sidewalk fun!
Save it for later!