Here's why:
* Refraction: This is the bending of light as it passes from one medium to another.
* Density and Speed: Light travels slower in denser materials.
* Snell's Law: This law describes the relationship between the angle of incidence (the angle at which light hits the surface), the angle of refraction (the angle at which light bends), and the indices of refraction of the two materials.
* Towards the Normal: When light moves from a less dense medium (like air) to a denser medium (like water), it slows down. This causes the light to bend towards the normal (an imaginary line perpendicular to the surface of the material).
Think of it like this:
Imagine light as a car traveling on a road. If the car suddenly enters a muddy field (the denser medium), it will slow down and change direction towards the center of the field. The normal line represents the direction the car would have continued in if it hadn't slowed down.
