Physics Uncovered on Instagram: "The index of refraction tells us how much light changes direction when it moves from one material to another. A higher number means the light slows down more and bends more as it enters the new medium. Examples: • Air has an index close to 1, so light barely bends. • Water has an index around 1.33, so light bends noticeably. • Glass has an index near 1.5, so light bends even more. This explains why a straw looks bent in a glass of water and why lenses, prisms, an