What physical principles does the phenomenon of diffraction illustrate?

Diffraction is a phenomenon that occurs when waves encounter an obstacle or a slit that is comparable in size to their wavelength. This principle illustrates the wave behavior of light, emphasizing that light does not just travel in straight lines, but can bend and spread out after passing through narrow openings or around obstacles.

In the case of light, when it passes through a small aperture or around the edges of an object, it creates characteristic patterns of dark and light regions, demonstrating how waves can interfere with one another. This behavior is fundamentally different from that of particles, which would travel in predictable straight paths. Thus, diffraction serves as a significant demonstration of light's wave nature, reinforcing key concepts in the realm of optics. Understanding diffraction is crucial as it sets the foundation for numerous optical applications, such as diffraction gratings used in spectroscopy.