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92 experiments / 15 branches

WHAT LIGHT DOES

Bending, bouncing, splitting, interfering, and painting the sky — six modules from Snell to the rainbow.

1

SNELL

n₁sinθ₁ = n₂sinθ₂ — and past the critical angle, a perfect mirror.

5 STAGES · 7 TERMS

2

LENS

Three rays, one meeting point — geometry and algebra agree to the last digit.

5 STAGES · 6 TERMS

3

MIRROR

Same equation as the lens — light forgets whether it bent or bounced.

5 STAGES · 6 TERMS

4

PRISM

Snell twice per color — and at minimum deviation, the prism measures its own glass.

5 STAGES · 8 TERMS

5

SLITS

Darkness made of light — d·sinθ = mλ, and only ⌊d/λ⌋ fringes exist.

5 STAGES · 8 TERMS

6

RAINBOW

The bow is a caustic — dD/dθ = 0 on a sphere: red 42.3° outside violet 40.6°, and a dark band above.

5 STAGES · 8 TERMS

THEORY IN PLAY — Interactive Physics ·

Pause at stages ←→ step · PgUp/Dn stage · Space play

Speed Loop scene

Given

Computed