Articles about Wave refraction
One characteristic of waves is refraction. Refraction occurs when a wave that originally traveled through one medium enters a different medium. For example, a sound wave initially moves through the air and then encounters a wall, some sound waves are reflected by the wall, some are refracted by the wall. Refraction means that sound waves are absorbed or transmitted in the wall, but the direction of propagation changes. The change in the direction of propagation occurs because the speed of the sound wave changes when it enters a different medium from the previous medium.