* Light and Refraction: Light travels in waves. When light travels from one medium to another (like from air to water), it changes direction. This bending of light is called refraction.
* Index of Refraction: Every material has a property called the index of refraction, which tells you how much the speed of light changes when it enters that material. Water has a higher index of refraction than air, meaning light travels slower in water.
* Why the Speed Changes: The speed of light is determined by the medium it travels through. In a denser medium like water, light interacts more with the molecules, causing it to slow down.
Here's a key point: The *frequency* of the light remains the same, but the *wavelength* decreases. This is why light bends when it enters water, and why objects submerged in water appear to be closer than they actually are.
