What gasses cause bubbles to form? How long of a bubble snake can you make with your breath?
Blowing bubbles outside is a classic past time and fun for all ages. But do you how bubbles actually form? In this experiment, you will learn how bubbles are formed and how the gasses from your breath create them.
Bubbles are pockets of soap and water that are filled with air – like your breath, which contains nitrogen, oxygen and carbon dioxide. When you combine soap and water together then blow air into the mixture, the soap forms a thin wall and traps the air – creating a bubble! The soapy film is composed of three layers: one layer of water molecules between two layers of soap molecules. Millions of these molecules will stick together to form the spherical shape of a bubble.
Soap bubbles aren’t the only bubbles you will find – in fact, you can find bubbles in lots of liquids like carbonated drinks (think soda pop) and even in plain water, you might be able to see small bubbles. It’s important to note that those bubbles will always be in the water or floating on the surface of the water unlike soap bubbles that can float freely in the air. Can you think of any other types of bubbles?
Have an adult use the precision knife or scissors to cut the bottom ½ inch off a plastic bottle.
The towel plays an important role in this experiment, as the dish soap is absorbed into the towel fibers until we use our breath to push our exhaled gas into a bubble.
You may notice some towels work better than others; the best ones are thick enough to absorb the bubble solution, but thin enough that you are can easily push air through the fibers.
And why do we add the food coloring to the towel instead of the water solution? Ideally, we want to create a multicolored chain of bubbles. If we add the food coloring to the towel, we can maintain sections of orange, red, green, blue, purple or whatever colors you chose! This is perfect for creating a rainbow bubble snake. However, if we had added all of these colors to the water solution, our water would turn dark black. That solution would give us a chain of black bubbles instead of a colorful bubble snake!
Keep trying out different color variations, different towel sizes, and make your observations.
When you are finished, remember to clean up when you are done by disposing of or recycling your materials.
This experiment was selected for Science at Home because it teaches NGSS Disciplinary Core Ideas, which have broad importance within or across multiple science or engineering disciplines.
Learn more about how this experiment is based in NGSS Disciplinary Core Ideas.