Soap Bubble rainbow

How Soap Bubbles Create Rainbow Colors: A Fun Look at Light Physics

Have you ever noticed that when you look at a soap bubble, there seems to be a whole miniature world of color swirling on its surface? As it floats through the air, its rainbow sheen shifts and dances, almost like magic. But behind that mesmerizing display is actually science.

The colorful patterns on a bubble aren’t just for show, they’re a fascinating example of how light interacts with thin layers of material. These tiny floating spheres offer a perfect chance to explore big scientific ideas in a fun and visual way. From color interference to light reflection, soap bubbles are packed with physics that’s easy to observe and exciting to learn.

Let’s explore how soap bubbles work, why they show color, and how they relate to the deeper science of light and vision.

CMY Cubes color mixing

What Is a Soap Bubble Made Of

A soap bubble isn’t just air with a bit of soap. It’s actually a structure of three layers:

  • A thin inner layer of soap

  • A middle layer of water trapped in between

  • A thin outer layer of soap

This sandwich-like film is extremely thin. Often less than athousandth of a millimeter. And it’s this thinness that lets us observe something called interference; the secret behind those stunning rainbow colors.

Why Do Bubbles Show Rainbow Colors

When sunlight hits a soap bubble, part of the light reflects off the outer surface. Another part passes through and reflects off theinner surface. Because these surfaces are so close together, the light waves interact with each other.

Some colors are amplified when the waves align. Others cancel out when the waves are out of sync. This process is called thin film interference, and it changes based on:

  • The thickness of the film

  • The angle of the incoming light

  • The angle of your eyes as you look at it

That’s why a bubble’s colors change as it floats or spins; its thickness is constantly shifting. Each swirl of color is a real-time physics lesson, showing how light can be shaped and reshaped by its environment.

What Makes the Colors Move

Bubbles don’t stay still. As they float, gravity pulls the water downward, causing the film to vary in thickness. Thicker parts reflect different colors than thinner parts. This is why you see swirling rainbow waves across the surface.


The movement isn’t just beautiful, it’s a direct result of physics at work. Watching this change is a simple way to understand that light interacts with materials, and that these interactions depend on structure and motion.

Why Do Bubbles Turn Clear Before They Pop

As the water in the bubble drains away, the film gets thinner and thinner. Eventually, it becomes too thin to reflect visible light. That’s when the bubble appears clear.

Once this happens, the bubble is close to bursting. With almost no water left in the film, the structure becomes unstable. In a second, it’s gone, but the science behind it lingers.

What This Teaches About Light and Vision

Soap bubbles reveal several key scientific concepts:

  • Light interference, where waves of light interact

  • Refraction, the bending of light as it passes through a substance

  • Transparency and reflection, which are about how much light bounces vs how much passes through

  • Color mixing, based not on pigments, but on how light behaves at tiny scales

These are the same ideas used in more advanced technologies, from fiber optics to camera lenses. But with a bubble, you can explore them in your backyard or classroom with just soap and water.

CMY Cubes and the Science of Color

Like bubbles, CMY Cubes are a tool for learning how light behaves. Instead of using thin films, they use transparent surfaces tinted cyanmagenta, and yellow. When light passes through or reflects off the cube, it changes based on:

  • Angle of light

  • Overlapping surfaces
    Viewer perspective

CMY Cubes let learners manipulate light with their hands. They provide a stable, repeatable way to explore color interaction, refraction, and subtractive mixing. Concepts that can be hard to visualize on their own.

Where bubbles are brief and chaotic, CMY Cubes offer a structured, tactile experience. Both, however, make abstract science visible, engaging, and memorable.

Why This Is a Powerful Teaching Tool

When science feels magical, learners stay curious. That’s the power of bubbles and transparent color tools — they create wonder while demonstrating real physics. These hands-on experiences:

  • Encourage observation and inquiry

  • Show that science exists in everyday life

  • Help explain complex topics in visual, accessible ways

  • Build connections between art, science, and play

Whether you’re a parent introducing STEAM ideas at home, an educator looking for fresh ways to teach optics, or just someone who loves beautiful questions, bubbles and CMY Cubes provide the perfect starting point.

Final Thoughts

Tiny rainbows inside a soap bubble aren’t just beautiful. They are science made visible. With every shimmer, spin, and pop, they demonstrate how light behaves in delicate and powerful ways.


Encouraging children and adults to explore these effects builds a deeper understanding of the world around them. And when the bubble pops, the learning doesn’t have to stop. Tools like CMY Cubes keep the conversation going, helping you see light from every angle.

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