Light and Refraction Interactive Simulation

When a light ray crosses the boundary between two materials, it bends — this is refraction. Snell's law (n₁·sinθ₁ = n₂·sinθ₂) quantifies the bend. When light travels from a denser to a rarer medium above the critical angle, no refracted ray exists: all the light reflects back into the first medium. Students can change medium 1 (n₁) and medium 2 (n₂) and compare what happens. Use it for physics inquiry with Grade 5, Middle School, and High School on a projector or student device.

Standards: NGSS MS-PS4-2

• Why a straw looks bent in a glass of water (air n=1 → water n=1.33)
• How a denser medium bends the ray closer to the normal
• What happens when light passes from glass back into air at a steep angle
• Reading Snell's law with your own n values and incident angle

1. 1Predict how changing medium 1 (n₁) will affect the refracted angle, then test the prediction.
2. 2Use evidence from the live calculation and visual to explain the result.

Questions teachers ask