Physics
What makes soap bubbles show a rainbow of colors?
Quick fact
The iridescent colors come from thin-film interference: light reflecting from the front and back surfaces of the soap film overlaps, and some wavelengths cancel out while others amplify, producing vibrant hues.
Why this is interesting
A soap bubble's colors aren't from pigment—they're created by light waves interfering with each other as they reflect off the soap film's two surfaces, creating colors that change as the film thins.