gen-explain-snell-s-law-of-refraction-as-you-would-to-a-capable-fa65

Explain Snell's law of refraction as you would to a capable student, in 3-4 sentences.

# Snell's Law of Refraction Snell's law describes how light bends when it passes from one transparent material into another, like from air into water. The law states that n₁sin(θ₁) = n₂sin(θ₂), where n₁ and n₂ are the refractive indices of the two materials, and θ₁ and θ₂ are the angles the light ray makes with an imaginary line perpendicular to the surface. Essentially, light changes direction because it travels at different speeds in different materials—when light enters a denser medium (higher n), it slows down and bends toward the perpendicular, and when it enters a less dense medium, it speeds up and bends away. This is why a straw appears bent in a glass of water!