Home▸Nature & Climate▸Rainbow & Optics - 2D Raindrop Ray Diagram and Rainbow Angles

🌈 Rainbow & Optics - 2D Raindrop Ray Diagram and Rainbow Angles

Trace sunlight through a raindrop with Snell refraction and internal reflection, find the 42 degree primary and 51 degree secondary rainbow angles from Descartes ray theory, and see Airy-theory colour and brightness painted across the sky.

Nature & Climate2DModerate60 FPS📱 Mobile-adapted💧 Water 💨 Air & Wind ⇄ 3D version

Details

CategoryNature & Climate

RenderingCanvas 2D

DifficultyModerate

Target FPS60

ControlsDroplet-medium dropdown (water/denser liquid/glycerol); impact-parameter slider dragging a highlighted ray across the droplet, with a Sweep button to animate it automatically; checkboxes to toggle the many-ray fan and the secondary (two-reflection) bow; a reset button restores all defaults. Live stat boxes report the highlighted ray's entry angle, refraction angle, total deviation and scatter angle, plus the scan-measured primary/secondary extrema for red and violet.

RainbowOpticsDispersionRaindropRay tracing

📖 Read the articleThe maths behind Rainbow & Optics - 2D Raindrop Ray Diagram and Rainbow Angles

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⚙ Under the hood

RainbowOpticsDispersionRaindropRay tracing

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install