The colors in the rainbow are red, orange, yellow, green, blue, indigo and violet. These always appear in the same order.
Rainbows are an arc of color that appear in the sky after particular weather conditions: a sunny sky and rain.
Raindrops in the air act as a prism, bending and splitting sunlight into its component colors and reflecting them back to the viewer. Humans perceive seven distinct colors in every rainbow although sometimes it is hard to spot all at once. Read on to learn why:
The first color of a rainbow is red. It forms the rainbow's outer arc and has the longest wavelength. Because light bends at 42 degrees to produce this color, humans can almost always see it, even if the other colors in the rainbow aren't apparent.
Orange is the second color of the rainbow, always appearing next to red. It is sometimes difficult to discern the orange in a rainbow because it blends in so much with the red. Many times it looks like the red in the rainbow simply fades off.
Yellow is the third color and a very prominent one in most rainbows. It tends to stand out and is usually visible, although in light-colored rainbows or in rainbows that appear next to a particularly bright sunny sky, it can fade away.
Green can be found in every rainbow next to yellow. It is difficult to see if the rainbow is against a bright blue sky. Green tends to stand out because it is the first cool color of the spectrum, meaning it contrasts with the warm colors (red, orange and yellow).
Blue is the fifth color of the rainbow and one that can easily go unnoticed because most of the times it blends in with the blue in the sky. This color is more easily seen in rainbows that appear when the sky is gray.
Indigo is the second to last color of the rainbow and is an intermediate wavelength between the two colors on either side of it. Indigo is one of the most easily forgotten colors of the rainbow because it is often unseen by the human eye when looking at a natural rainbow.
Violet is the final color of the rainbow, making up the inner outline of the rainbow's arc. Its wavelength is the shortest of the rainbow colors. It can blend in with the blue, but is often visible to the naked eye and will stick out from the rest of the colors enough to be noticed. Many times the bright violet color of the rainbow will stand out against white clouds or grayer skies.
The most common method of memorizing the colors of the rainbow is to use a mnemonic device or mental shortcut. Here, the mnemonic device is the fictional name "Roy G. Biv." Each letter in this name stands for the color of the rainbow in the order it appears.
