Final answer:
Refraction of a sound wave occurs when it bends as it moves through the boundary between two media of different densities, changing its speed and wavelength.
Step-by-step explanation:
The refraction of a sound wave occurs when the sound wave bends as it passes through the boundary between media with different densities. This change in path happens because different media have different properties, such as density, that affect a wave's speed and wavelength. When a wave, including sound or light, moves from one medium to another (for example, from air into water), it experiences a change in speed, which results in the wave bending—a phenomenon known as refraction.
Refraction is an important concept in physics, particularly in the study of waves and optics. According to Snell's law, the extent of bending of the wave at the interface depends on the angle of incidence and the relative speeds of light in the two media. This law helps in understanding how lenses and other optical devices function.