Rainbow in a Raindrop

Also called

rainbow · raindrop · dispersion · dispersion of light · refraction · total internal reflection · spectrum · VIBGYOR · seven colours · primary rainbow · secondary rainbow · 42 degrees · water drop prism · colourful world · इंद्रधनुष · वर्ण विक्षेपण · अपवर्तन

Topics

• A rainbow is a natural spectrum made by sunlight in tiny water drops after rain, seen with the sun behind you.
• Each drop acts like a small prism: light refracts on entering, reflects inside, and refracts again on leaving.
• Dispersion: the drop bends violet most and red least, so the colours separate as they refract.
• The light that reaches your eye leaves each drop at about 42° from the direction of the sunlight (red 42°, violet 40°).
• Red reaches you from drops a little higher in the sky and violet from drops lower down, so red is outside.
• Millions of drops at that angle from your eye make one arc: a rainbow is a circle centred opposite the sun.
• A fainter secondary bow forms from light reflected twice inside the drops, at about 51°, with the colours reversed.
• No two people see exactly the same rainbow, because each eye sees light from a different set of drops.

About this model

A GLB file of about 659 KB, shown in Lably's 3D viewer and, on a phone, placed in your room with AR. Credit: Model, science and animation: Lably (built procedurally with three.js; no downloaded meshes). | CC BY 4.0. Original geometry and animation made for Lably.

More in Science

1

1 m reflecting telescopeClass 6–123D model

1 m reflecting telescopeClass 6–123D model

A

Aerobic vs Anaerobic RespirationClass 103D model

Aerobic vs Anaerobic RespirationClass 103D model

A

Alkanes Grow and IsomersClass 103D model

A

Amoeba and Paramecium FeedClass 103D model