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Double Rainbows, Double Happiness

On a cloudy day, I was walking on a trail next to a lake, and it started to drizzle. All of a sudden, a pair of rainbows appeared. Rainbows are beautiful displays of physics in action, illustrating the principles of refraction, dispersion, and reflection. Refraction occurs when light enters water droplets in the atmosphere at an angle to the normal. Because light travels faster in air than in water, light bends from its normal line. Once inside the droplet, the light is dispersed into its component colors: red, orange, yellow, green, cyan, blue, and violet. The dispersion happens because different colors of light have different refractive indices, and thus red bends the least, while violet bends the most. The dispersed light exits the droplet, and the light refracts again, spreading out further and creating the rainbow's wide arc and distinct colors. A primary rainbow forms through one internal reflection, appearing more vivid with red on the outer edge and violet on the inner. Conversely, a secondary rainbow, resulting from two reflections, shows reversed colors and is fainter and higher in the sky. The rainbows are reflected in the lake water, as the light rays forming the rainbows can directly reflect off the surface of the water just as they could off a mirror. The reflected rainbows appear as a continuation of the main rainbows below the horizon line, creating a beautiful bridge, and it reminds us that beauty and light can emerge from even the most fleeting moments.