This is a great example of homeschool science for those who are curious about our “classroom”. It’s also a wonderful sensory activity for the younger kids. There’s a lot of fluffy foam involved! 

Once we finished our schoolwork for the morning I had to repeat this experiment just so the kids could have time playing in the suds. I gave them cups and spoons, but they definitely preferred using their bare hands. Who wouldn’t!? Admittedly this can get messy, but the good news is that clean up is easy, especially if you follow my advice and use a sink or deep baking dish. 

We took this experiment from the textbook Science in the Ancient World by Berean Builders. If you’re in the market for a homeschool science curriculum, I highly recommend this company. As exemplified by this activity, the experiments are hands-on and require simple household products you either have laying around or can easily pick up at your local store.

For this lesson, our focus was an ancient scholar named Democritus (c. 460 BC – c. 370 BC), who is credited as one of the earliest scientists to discuss the existence of atoms. We’ve also discussed the various ways scientific theory changes over time as new evidence suggests different explanations. While Democritus helped introduce the world to atoms, not all of his theories were true. In fact, his belief that atoms are indivisible (unable to be broken into smaller parts) lasted about 2,000 years until German scientists split the uranium atom in 1938! 

Democritus also believed that the difference between atoms is primarily based on shape. For example, he believed iron atoms have hooks linking them together to make them hard, salt atoms have sharp edges explaining its taste, and water atoms have a smooth surface that makes water slippery. However, we now know this isn’t true. Salt isn’t made out of salt atoms. Water is not made out of water atoms. Iron is not made out of iron atoms. 

Instead, most things are made out of molecules, or a combination of atoms and ions joined together. In this experiment, we demonstrate the ability to break apart molecules to produce something different. It’s simple…

What you need

  • 1 cup hydrogen peroxide
  • 1 TBS active dry yeast 
  • ¼ cup dish soap
  • ¼ cup warm tap water

Other equipment:

  • A tall glass
  • A small glass
  • An empty sink or a deep baking dish to control the mess. 


1. In a small glass, combine yeast and warm water. Stir with a spoon and let it sit for roughly 2 minutes. 

2. Pour hydrogen peroxide into the taller class, followed by the dish soap. Swirl the glass so the two liquids mix (do not use the same spoon you used for the water and yeast). 

3. Place the tall glass in an empty sink or the middle of a deep baking dish. After allowing the yeast mix to sit for a couple of minutes, slowly pour the contents of the small glass into the tall glass containing hydrogen peroxide and dish soap. 

Watch what happens…

You just witnessed decomposition! To put it simply, we watched as something broke down into smaller things.

The hydrogen peroxide is made up of molecules containing 2 hydrogen and 2 oxygen atoms. Being an unstable arrangement, the hydrogen molecules try to get rid of the oxygen molecules. This is why we store hydrogen peroxide in closed and dark containers. Light and air speed this process along, which will eventually leave you with…water. 

Yeast contains a chemical (catalase) that also accelerates decomposition. So when we mixed the dissolved yeast with the hydrogen peroxide, the hydrogen peroxide molecules released their oxygen atoms. Oxygen, being a gas, escaped into the soap and created the foam we used to visually see this process take place. 

Neat huh? The kids certainly thought so. We will revisit this lesson in later years when we’re ready to dive into a deeper understanding of atomic and molecular science. For now, it was a fun way to introduce the concept.

*As a side note, I am not affiliated with Berean Builders, nor was this a promotional post beyond my personal experience and recommendation