The seven colors of the rainbow, in order, are red, orange, yellow, green, blue, indigo, and violet. The easiest way to remember them is with the acronym ROY G. BIV, where each letter stands for one color. But there are several other tricks worth knowing, especially if you’re helping a child learn them or want to understand why there are seven colors in the first place.
The ROY G. BIV Method
The most popular mnemonic is to treat the first letters of the seven colors as a name: ROY G. BIV. Say it out loud a few times and it sticks. R is red, O is orange, Y is yellow, G is green, B is blue, I is indigo, and V is violet. The order runs from the outside of the rainbow’s arc (red) to the inside (violet).
If a person’s name doesn’t do it for you, sentence-based mnemonics work just as well. The most traditional is “Richard Of York Gave Battle In Vain,” a phrase used in British schools for generations. Another option is “Read Out Your Good Book In Verse.” You can also invent your own sentence using the letters R-O-Y-G-B-I-V. The sillier or more personal the sentence, the easier it tends to stick in memory.
Hands-On Ways to Learn the Order
For young children, or for anyone who learns better by doing than by reciting, physical activities can lock in the sequence faster than a phrase. Lining up colored objects (blocks, crayons, pom poms, candies) in ROYGBIV order turns the abstract sequence into something you can see and touch. Drawing a rainbow with chalk on a sidewalk, painting handprints in each color, or filling in a rainbow outline with fingerprints all reinforce the order through repetition and muscle memory.
Music helps too. Several children’s songs set the seven colors to a melody, which takes advantage of the same principle that makes you remember song lyrics from decades ago. Even dancing with colored ribbons in the correct sequence can build the association for preschool-aged kids.
Why Exactly Seven Colors?
The rainbow doesn’t actually have seven neat stripes. Sunlight contains a continuous spectrum of wavelengths, blending smoothly from one hue to the next. The reason we say there are seven distinct colors goes back to Isaac Newton. Around 1665, Newton passed white light through a prism and watched it spread into a band of color. He chose to divide the spectrum into seven parts because he believed visible colors should mirror the seven notes of the musical scale.
Newton even drew diagrams mapping each color to a musical note, arranging them on a color wheel that followed the structure of the Dorian mode. He specifically added orange and indigo to fill the spots where half steps occur in the scale, between E and F and between B and C. As physicist and author Peter Pesic has noted, “It has no justification in experiment exactly; it just represents something that he’s imposing upon the color spectrum by analogy with music.” In other words, seven is a cultural choice, not a hard physical boundary.
What the Colors Actually Are
Each color in the rainbow corresponds to a different wavelength of visible light. The human eye detects wavelengths from about 380 to 700 nanometers. Red sits at the long-wavelength end, around 700 nanometers, while violet sits at the short-wavelength end, around 380 nanometers. Shorter wavelengths carry more energy, which is why ultraviolet light (just beyond violet) can cause sunburn while infrared (just beyond red) feels like warmth.
Here’s the order from longest wavelength to shortest:
- Red (longest wavelength, lowest energy)
- Orange
- Yellow
- Green
- Blue
- Indigo
- Violet (shortest wavelength, highest energy)
This is also why the colors appear in a fixed order in every rainbow. Raindrops act like tiny prisms, bending each wavelength by a slightly different amount. Red light bends the least and appears on the outer edge of the arc, while violet bends the most and appears on the inner edge.
Double Rainbows Flip the Order
If you’ve ever seen a second, fainter rainbow above the primary one, you may have noticed the colors run backward. In a primary rainbow, the order from top to bottom is red through violet. In a secondary rainbow, violet sits on top and red on the bottom. This reversal happens because light inside each raindrop reflects twice instead of once before exiting, which flips the sequence. The secondary rainbow also forms at a wider angle, about 50 to 53 degrees from the point directly opposite the sun, compared to 40 to 42 degrees for the primary bow.
Not Every Culture Sees Seven Colors
The seven-color rainbow is far from universal. Different languages carve the color spectrum into different numbers of categories, and this shapes how people perceive and group colors. English has 11 basic color terms (red, orange, yellow, green, blue, purple, pink, brown, black, white, gray), which makes distinguishing indigo from blue fairly intuitive for English speakers. But the Himba language of Namibia has only five basic color terms, each covering a much broader range. What an English speaker would separate into red, orange, and pink, a Himba speaker groups under a single word, “serandu.” Dark blue, dark green, dark brown, dark purple, and black all fall under “zoozu.”
Research in developmental psychology has shown that children across cultures acquire color categories gradually, starting from an uncategorized perception of color as a smooth continuum and slowly learning the boundaries their language draws. So while ROY G. BIV is a handy framework, it reflects the English-speaking tradition more than any fixed truth about how many colors a rainbow contains. Some cultures teach five, some six, and some simply describe it as a smooth blend of light.