What phenomenon describes the effect of sound bouncing back to create an echo?

Reflection describes the phenomenon of sound bouncing off a surface and returning to the listener, which is what creates an echo. When sound waves encounter a surface, such as a wall or a mountain, some of the sound energy is reflected back towards the source. This principle is essential in understanding how echoes occur in environments like canyons or large empty rooms, where sound can travel, reflect, and return to the listener's ears, creating that distinct echo effect.

In contrast, refraction involves the bending of sound waves as they pass through different mediums, which does not apply to the bouncing back of sound that characterizes an echo. Diffraction refers to the bending of waves around obstacles or through openings, affecting how sound travels but not directly creating an echo. Absorption pertains to how sound energy is absorbed by surfaces rather than reflected, further distinguishing it from the concept of reflection that is critical for echo formation.