Why Rainbows Form as Arcs: Sunlight, Refraction, and Nature.

Rainbows appear as arcs because of the interaction between sunlight and raindrops.When sunlight hits a raindrop , the light bends and splits into different colors.
This process is called refraction. Each color emerges at a specific angle, forming a circle. However, the ground usually hides the bottom half, so we see an arc. The sun's position also affects the rainbow's visibility.
If the sun is high️, the rainbow appears lower. In special cases, like from a mountain or hot-air balloon, you might see a full-circle rainbow.