Here's why:
* Refraction is the change in direction of light as it passes from one medium to another. This change in direction is caused by the change in the speed of light as it travels through different materials.
* When light enters a denser medium (like from air to water), it slows down, causing the light to bend towards the normal (an imaginary line perpendicular to the surface).
* When light enters a less dense medium (like from water to air), it speeds up, causing the light to bend away from the normal.
This bending of light is what allows us to see things like rainbows, the way objects look distorted underwater, and even how our eyes work.
