Chapter 31, Problem 28A

Seashells, butterfly wings, and the feathers of some birds often change color as you look at them from different positions. Explain this phenomenon in terms of light interference.

To determine

To Explain: Seashells, feathers and wings change color due to light interference.

Explanation of Solution

Introduction:

The superposition of two or more light waves occupying the equal space can be defined as interference of light. Hence, a pattern of interference is formed within which the amplitudes of waves may be increased, decreased or cancel.

The bright fringes occur when the reflected waves arrive in phase while the dark fringes occur when the reflected waves arrive out of phase. Now as one looks at seashells, fringes or wings from different positions, they can be seen in different colors with different optical paths due to which the different wavelengths cancel each other and tends to produce different colors.

Conclusion:

Hence, due to destructive interference of light, seashells, butterfly wings and feathers of some birds change color as seen from different positions.