Refraction of a sound wave occurs when it passes at an angle from one medium into another in which the speed of sound is different.

Here's why:

* Speed of sound: The speed of sound depends on the properties of the medium it travels through. For example, sound travels faster in solids than in liquids, and faster in liquids than in gases.

* Angle of incidence: When a sound wave strikes the boundary between two mediums at an angle, part of the wave is reflected and part of it is transmitted into the second medium.

* Change in direction: The transmitted sound wave will change direction (refract) due to the difference in speed of sound between the two mediums.

Think of it like this:

Imagine a car driving from a smooth road onto a muddy field. The car will slow down and change direction because it's encountering a different surface. Similarly, a sound wave will change direction as it enters a medium where it travels at a different speed.

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