Chapter 31, Problem 33A

The interference colors seen in soap bubbles are not reds, greens, and blues, but instead are magentas, yellows, and cyans. Why?

To determine

To Explain: The colors that are observed in soap bubbles are more of magentas, yellows, and cyan.

Explanation of Solution

Introduction:

In general, different colors are seen on soap bubbles. This is due to the interference of light rays that fall on the bubbles. Majorly the bubbles will appear with magenta, yellow, and cyan colors.

A soap bubble forms when the water molecules are trapped between two layers of soap molecules. Therefore, a soap bubble will have an inner layer and outer layer.

When light falls on the soap bubble, a part of the light rays will get reflected from the top surface and remaining will refract into inner layer and then get reflected from the inner layer. This means, there will be two rays- one reflected from inner layer and other reflected from outer layer. When the path difference between these two rays equal to certain wavelength of incident light, constructive interference takes place and the bubble show colors.

The color of a soap bubble depends on its thickness. As the thickness changes, the path difference between light will get changed. This in turn changes the color of the soap bubble.

In the case of bubble with more thickness, blue and green colors will dominate. As the thickness goes down, the dominant colors in soap bubbles are magentas, yellow and cyan colors.