The rainbow lie

The error: A rainbow has seven colors

We are, no doubt, all familiar with the old phrase “Roy G. Biv” used to remember the colors of the rainbow: red, orange, yellow, green, blue, indigo, violet. This series of colors was coined by Newton who initially excluded indigo and violet. While a rainbow does appear to have seven colors, it is, in fact, one continuous spectrum of color and it is merely an artifact of human color perception that makes it appear to be a series of bands. There are also things called supernumerary rainbows which have more than 7 bands visible to the human eye (pictured above – note the extra green and purple bands at the bottom of the rainbow).