Why Can We See Rainbows?

Full transcript

Have you ever wondered why a beautiful arc of colors appears in the sky after it rains? The answer lies in the amazing science of light. Sunlight looks white or yellow to our eyes, but it is actually made up of every color of the visible spectrum all mixed together into one beam. When sunlight enters a tiny raindrop floating in the air, it slows down and bends slightly, a process that scientists call refraction. Because each color of light bends at a slightly different angle, the raindrop separates the white light into all its individual colors, spreading them apart. The separated colors then bounce off the inside back wall of the raindrop in a process called internal reflection, sending them back outward toward you. Millions of raindrops all do this at once, and each drop sends a specific color to your eye depending on its position in the sky, building the full arc. So every rainbow is completely personal — it is created just for your eyes, at that exact moment, making it one of nature's most magical optical illusions.