The change in the wave's speed causes the direction of propagation to change.
Here's a breakdown:
* Wave Speed: The speed of a wave depends on the medium it travels through. For example, light travels faster in air than it does in water.
* Refraction: When a wave transitions from one medium to another, its speed changes. This change in speed causes the wave to bend or change direction. The amount of bending depends on the difference in speed between the two media and the angle at which the wave strikes the boundary.
* Why It Happens: Think of it like this: Imagine a car driving on a paved road and suddenly hitting a patch of sand. The car will slow down and change direction slightly. Similarly, when a wave slows down as it enters a denser medium, it bends towards the normal (an imaginary line perpendicular to the boundary). If the wave speeds up, it bends away from the normal.
In summary, refraction is a direct consequence of the change in wave speed as it transitions between different media.
