The phenomenon responsible for forming rainbows is refraction, which occurs when sunlight passes through water droplets in the atmosphere. As light enters and exits the droplets, it bends and spreads out into its component colors, creating a spectrum seen as a circular arc in the sky. Additionally, reflection inside the droplet enhances this effect, adding to the vividness of the rainbow. The result is a beautiful display of colors: red, orange, yellow, green, blue, indigo, and violet, often appearing after rain when conditions are suitable for sunlight and moisture.