# PROMPT
Explain how rainbows form, illustrate with two diagrams.

# OUTPUT
Rainbows are a beautiful optical phenomenon that occurs when sunlight interacts with water droplets in the atmosphere. Here is a step-by-step explanation of the process:

1. **Refraction and Dispersion**: When a beam of sunlight enters a spherical raindrop, it slows down and bends, a process called refraction. Because different colors of light have different wavelengths, they bend at slightly different angles, causing the white light to split into its component colors (dispersion).

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2. **Internal Reflection**: After entering the drop, the light travels to the back surface. It then reflects off the interior of the droplet, bouncing back toward the front. This reflection is what redirects the light toward the observer.

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3. **Secondary Refraction**: As the light exits the raindrop, it undergoes a second refraction. This final bending of the light rays directs the separated colors toward the viewer's eye, completing the journey from the sun to the observer.

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4. **The Observer's Perspective**: For a rainbow to be visible, the sun must be behind the observer. The light rays from thousands of different raindrops are directed toward the eye at a specific angle, creating the illusion of a curved band of color.

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5. **The Geometry of the Arc**: The rainbow forms a circular arc because the light rays from all the droplets that reach the observer's eye are at the same angle. This creates a perfect semi-circle in the sky.

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6. **The Final Rainbow**: The result is a vibrant, multi-colored arc. The colors are arranged in a specific order—red on the outside and violet on the inside—due to the way light is refracted and reflected within the droplets.

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