**Any time you experiment or demonstrate with liquids, heat, or glass you should use protective eye gear -- kids LOVE wearing science goggles!**
Let your kids direct the experiment! The foam created is safe to touch. It is simply water, oxygen gas and soap, so if your child has no soap allergies, they can experience and experiment with the texture, temperature, and feel of the foam! If your child does have soap allergies or sensitive skin (or if you're just concerned), I'd encourage you to use gloves--you can still enjoy touching it with gloves on!
Water bottle or soda pop bottle
Pan to catch the toothpaste (or do this experiment outside)
2 Tbls warm water
1 tsp yeast
½ cup 6% hydrogen peroxide (It is important to use at least 6%. You can use 8% or more (available on Amazon), or you can use Salon Care Professional Stabilized Formula. 20 Volume Clear Developer from Sally Beauty Supply works fine too. 3% from the grocery store will NOT work as well. 😉 )
4-5 drops of food coloring
Squirt of dish soap
Set a water bottle or soda pop bottle in the middle of a pan to catch the toothpaste.
Mix warm water and yeast in a separate container and swirl together for a minute. The yeast will catalyze (or speed up) the reaction. Woo hoo!
Mix peroxide, food coloring and dish soap in the soda pop bottle.
Pour yeast mixture into the soda pop bottle and watch the reaction.
How it Works:
The reaction is summarized by this formula:
2 H2O2 --> 2 H2O + 02.
Hydrogen peroxide (H2O2) naturally breaks down into water and oxygen. It is stored in opaque containers to help slow down this process. Catalase (an enzyme in all living things, including yeast) speeds up the reaction. Dish soap catches the oxygen and makes bigger bubbles and the food coloring makes it look cool. The foam and bottle feel warm because the reaction is exothermic--it releases energy as heat.
I found this peroxide (6%) on Amazon and it can be an Amazon Smile donation too!