Here's why:
* Refraction: This bending of light as it passes from one medium to another is called refraction.
* Index of Refraction: The speed of light in a material is related to its refractive index (n). A higher refractive index means the light travels slower.
* Snell's Law: This law describes the relationship between the angle of incidence (angle at which light hits the surface) and the angle of refraction (angle at which light bends). It states that the ratio of the sines of these angles is equal to the ratio of the refractive indices of the two materials.
In simpler terms:
Imagine light traveling from air (high speed) to water (lower speed). When the light hits the water surface, it slows down. This slowing down causes the light ray to bend closer to the normal (an imaginary line perpendicular to the surface).
Example: You can see this phenomenon when you look at a straw in a glass of water. The straw appears to be bent at the point where it enters the water.
