Which phenomenon allows waves to bend around obstacles?

Diffraction is the phenomenon that allows waves to bend around obstacles or spread out as they pass through openings. This bending occurs because waves, such as sound or light, have the ability to navigate around edges and obstacles in their path. The degree of diffraction depends on the wavelength of the wave and the size of the obstacle or aperture; longer wavelengths are more likely to diffract significantly compared to shorter wavelengths.

In practical terms, diffraction is observed in many everyday situations. For instance, when sound waves travel through a doorway, they spread out into the room rather than traveling in a straight line. This is why you can hear someone speaking even when they are not directly in your line of sight. Similarly, light waves can also exhibit diffraction, allowing them to bend around corners or through small openings, contributing to phenomena such as patterns and colors seen when light passes through a diffraction grating.

Refraction involves waves changing direction as they pass from one medium to another, reflecting changes in speed but does not involve bending around obstacles. Reflection refers to waves bouncing off a surface at an angle, and absorption is the process where waves lose energy as they pass through a medium. Thus, diffraction is the principle that specifically explains the bending around obstacles.