Rainbows are born when sunlight interacts with raindrops, creating a colorful arc in the sky. This happens through a combination of refraction, reflection, and dispersion.
Here's a breakdown of the process:
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Sunlight: Sunlight, which appears white, is actually composed of all the colors of the rainbow.
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Raindrops: Raindrops act as tiny prisms.
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Refraction: When sunlight enters a raindrop, it slows down and bends. This bending is called refraction. The amount of bending depends on the wavelength (color) of the light.
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Dispersion: Because different colors of light have different wavelengths, they bend at slightly different angles. This separates the white light into its constituent colors, a process called dispersion.
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Reflection: After refraction, the separated colors of light travel to the back of the raindrop, where they are reflected.
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Second Refraction: As the reflected light exits the raindrop, it refracts again, further separating the colors and amplifying the effect.
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The Rainbow: The separated and intensified colors then travel to the observer's eye, creating the perception of a rainbow. Because of the angles involved, a rainbow appears as an arc with red on the outside and violet on the inside.
In summary, the "birth" of a rainbow involves sunlight being refracted, dispersed, and reflected by raindrops, separating white light into its constituent colors and creating the colorful arc we observe. The angle at which the light is refracted and reflected creates the bow shape.