Adjust the incident angle to observe light refraction at the air-water interface. Total reflection occurs when the incident angle exceeds 48.6°
Snell's Law: n₁·sin(θ₁) = n₂·sin(θ₂)
Where n₁=1.00 (air), n₂=1.33 (water), critical angle ≈ 48.6°
When light passes from one medium to another, it bends due to changes in speed - this phenomenon is called refraction. According to Snell's Law, the incident and refracted angles satisfy: n₁·sin(θ₁) = n₂·sin(θ₂), where n₁ and n₂ are the refractive indices of the two media.
When light travels from a denser medium (like water) to a rarer medium (like air), if the incident angle exceeds the critical angle, light won't refract into the second medium but instead reflects entirely back into the original medium - this is total internal reflection.