Rainbows form when sunlight interacts with water droplets in the atmosphere through a process called refraction and reflection. The sequence of events is:
- Sunlight enters a water droplet and bends (refracts)
- The light reflects off the back of the droplet
- As it exits, the light separates into different wavelengths (colors)
Each color we see in a rainbow appears at a specific angle relative to the incoming sunlight. This is why rainbows always appear opposite the Sun and why no two people see exactly the same rainbow – the position depends on the observer’s location. The classic rainbow colors (ROYGBIV) appear because water droplets act like tiny prisms, separating white light into its component colors.