The Magic Behind Soap Bubbles

Do you enjoy playing with soap bubbles? Have you ever wondered how the perfect bubble emerges just by dipping the bubble wand into a thin soapy liquid and blowing air? The chemical phenomenon behind the formation of the soap bubble is called self assembly. It’s similar to a group of students assembling themselves to form different shapes to cheer their teams at sports games. Self assembly is a process in which an organized structure is automatically formed from individual components as a result of specific local interactions between the components.

In the case of soap bubbles, when you blow the air onto the soapy water, the soap and water molecules organize themselves into thin layers. Bubbles are made of alternating thin layers of soap molecules and water molecules, just like a sandwich is arranged with layers. The property of self assembly is the reason that when you blow the air into soap, it forms a bubble, rather than soap water flying off into the air. Now, coming to the magic-like part, soap molecules have two different types of edges, one that likes water- hydrophilic- and the other that doesn’t like water- hydrophobic. So, whenever there is even a little water present around the soap, the soap molecules form a layer with hydrophilic ends attracted to the water molecules on one side and the hydrophobic ends on the other side and the two layers form a bubble! 

There is also another magic-like phenomenon that happens with soap bubbles. They all contain the colors of the rainbow! It is because the thin layers of soap bubbles diffract different colors of light depending on the thickness of the layers. These colors change as the soap bubble glides through the air. With this, we now know that even with simple things we see in our daily lives are based on hidden systematic scientific concepts that seem like magic!

Soap Bubble Structure

Picture Source: chemistry.ku.edu