Why does a straw look bent in water?

Answer: Light refracts at water surface

Water pressure bends the straw — Wrong. The straw isn't actually bent. It appears bent because light refracts (bends) when crossing from water to air, changing the angle we see.

Eyes see underwater differently — Wrong. Eyes work the same. The bent appearance is real optical refraction—light changes direction crossing from water to air due to density difference.

Light refracts at water surface ✓ — Correct! Light travels at different speeds in different materials. When light from the submerged part travels from water to air, it bends (refracts) because air is less dense. This makes the underwater portion appear offset from the above-water portion. It's refraction—light bending at interfaces!