Rainbows are formed when sunlight interacts with water droplets in the atmosphere through the processes of refraction, reflection, and dispersion. As sunlight enters a water droplet, it slows down and bends (refraction), spreading into its constituent colors because different wavelengths of light bend at different angles. Inside the droplet, the light reflects off the inner surface, and as it exits, it refracts again, further separating the colors. This separation creates the distinct spectrum of colors seen in a rainbow: red, orange, yellow, green, blue, indigo, and violet (ROYGBIV), with red bending the least and violet the most. The circular arc of the rainbow is visible when sunlight, water droplets, and the observer’s eyes align at specific angles, typically 40° to 42°. Occasionally, a fainter secondary rainbow with reversed color order appears outside the primary rainbow, resulting from a second internal reflection within the droplets. Rainbows beautifully demonstrate the physics of light and offer a vivid display of nature’s optical phenomena.