Here's why:
* Light travels at its fastest speed in a vacuum. This speed, known as the speed of light, is approximately 299,792,458 meters per second.
* When light enters a medium like air or water, it interacts with the atoms and molecules in that medium. This interaction causes the light to slow down.
* The denser the medium, the slower the light travels. Water is denser than air, so light travels slower in water.
This change in speed is what causes light to bend when it moves from one medium to another, a phenomenon known as refraction.
