Why does sound bend around corners more easily than light?

Sound bends around corners more easily than light because of a wave phenomenon called diffraction. Diffraction occurs when waves encounter an obstacle or aperture, causing them to spread out into the region of the geometric shadow.12

The extent to which a wave diffracts is primarily determined by the relationship between its wavelength and the size of the obstacle it encounters. Diffraction is most pronounced when the wavelength of the radiation is comparable to the linear dimensions of the object.1

Audible sound waves typically have wavelengths of about one meter, which is similar in scale to many common objects and architectural features, allowing them to diffract easily around corners. In contrast, visible light has an extremely short wavelength—only a fraction of a micrometre—making its diffraction around large objects negligible to the human eye. Consequently, while light appears to travel in straight lines, sound waves are long enough to bend around obstacles and reach areas that are not in the direct line of sight.21