what makes a rainbow

A rainbow is made by the interaction of sunlight with raindrops through a process involving refraction, dispersion, internal reflection, and second refraction. When sunlight enters a raindrop, it bends (refracts) because light travels slower in water than in air. This bending separates the sunlight into its component colors (dispersion). The light then reflects off the inside surface of the raindrop and exits the drop, refracting again and spreading those colors toward the observer. The observer sees these colors as a circular arc with red on the outer edge and violet on the inner edge. The sun must be behind the observer, and rain must be in front to see the rainbow. The visible colors—red, orange, yellow, green, blue, indigo, and violet—are created because each color bends at a slightly different angle due to its wavelength. The combination of refraction, reflection, and dispersion in many raindrops creates the colorful rainbow that appears in the sky, usually seen as a semi- circular arc due to the ground blocking the rest of the circle.