Where Can You Find Iridescence In Nature?
Iridescence isn't hard to find in nature; a popular example is a soap bubble. In this instance, light passes through the top layer of the bubble, and the rest of the light hits the bottom layer, where some of it's reflected again. If the phase of these two light waves is different by a multiple of one wavelength, they have constructive interference, which is what happens in iridescence.
from Stuff You Should Know
Key Facts In This Video
When the wavelengths of light that hits the top half of a bubble and the light reflected from the bottom of the bubble match up, iridescence occurs. (0:09)
Iridescence is caused by constructive interference. (0:25)
Examples of iridescence are fish scales, bubbles, peacock feathers, oyster shells, and more. (0:42)