Which phenomenon can cause a wave to change direction when hitting a barrier?

The phenomenon that causes a wave to change direction when it encounters a barrier is reflection. When a wave strikes a barrier, it can bounce back off the surface. This is commonly observed with sound waves, light waves, and water waves. For instance, when light hits a mirror, it reflects back, allowing us to see our image. Reflection obeys the law of reflection, which states that the angle of incidence (the angle at which the wave hits the barrier) is equal to the angle of reflection (the angle at which the wave bounces off).

In contrast to reflection, diffraction refers to the bending of waves around obstacles and openings, while refraction is the bending of waves as they pass from one medium to another, due to a change in speed. Compression relates to the change in pressure within a medium, rather than a change in the direction of a wave. Each of these concepts relates to wave behavior, but reflection specifically addresses the interaction of waves with barriers and their resulting change in direction.