Chapter 14, Problem 13RQ

To determine

The reason behind variety of colors in soap bubble.

Answer to Problem 13RQ

The reason behind variety of colors in soap bubble is the phenomenon called iridescence.

Explanation of Solution

The phenomenon called iridescence occurs from the interference of reflected light from the inside and outside surfaces. This creates a colorful spectrum visible to the observer’s eye. When a color is canceled, its complementary colors are observed.

The soap bubble appears iridescent in white light when the thickness of the soap film is about the same as the wavelength of light. At this thickness, destructive interference occurs and the wavelength gets canceled. Whatever color is canceled by interference, the light seen is its complementary color, which are the remaining wavelengths from the white light.

Conclusion:

Therefore, the reason behind variety of colors in soap bubble is the phenomenon called iridescence.