A rainbow is a natural phenomenon that displays seven distinct colors. These colors, in order from the outer edge to the inner edge, are red, orange, yellow, green, blue, indigo, and violet. This sequence is often remembered using the acronym ROYGBIV. Rainbows occur when sunlight passes through water droplets in the atmosphere, causing the light to bend and separate into its component colors. This process is known as refraction. Rainbows are typically seen after rain when the sun shines, creating a beautiful arc of colors in the sky.