Kids have fun learning the order of the hues of the rainbow and the color wheel by singing this song: red, orange, yellow, green, blue, purple. Elementary art teachers use this song as the first step in learning color theory along with a color wheel for a visual aid. This song makes Warm and Cool color groupings easy to learn too -- just sing the first 3 colors for Warm Colors (red, orange, yellow) and the second 3 colors for Cool Colors (green, blue, purple) -- Wee!