Skip to content

Snell's Law: Refraction

Run the Snell's Law MicroSim Fullscreen

About This MicroSim

This simulation demonstrates Snell's Law, which describes how light bends when passing from one medium to another. The amount of bending depends on the indices of refraction of both media.

Key Concepts

  • Index of Refraction (n): How much a medium slows down light
  • Snell's Law: n₁ sin θ₁ = n₂ sin θ₂
  • Total Internal Reflection: When light cannot refract out of a denser medium
  • Critical Angle: The incident angle at which TIR begins

Controls

Control Description
Angle slider Adjust angle of incidence
Top medium Select upper medium (Air, Water, Glass, Diamond)
Bottom medium Select lower medium
Swap Media Exchange the two media

Observations

  • Light bends toward the normal when entering a denser medium
  • Light bends away from the normal when entering a less dense medium
  • Total internal reflection occurs only when going from denser to less dense medium at angles above the critical angle