Diffraction is a fascinating phenomenon that occurs when a wave encounters an obstacle or aperture. It is a characteristic behavior of all types of waves, including light, sound, and water waves. When a wave encounters an obstacle or aperture that is comparable in size to its wavelength, it bends around it and spreads out. This bending and spreading out of the wave is known as diffraction.

One common example of diffraction is the bending of light waves around a door frame. When light passes through a narrow door opening, it spreads out and creates a diffraction pattern. This can be observed by standing in a dark room with a narrow beam of light entering through a small opening. As the light passes through the opening, it diffracts and creates a pattern of light and dark regions.

Another example of diffraction is the phenomenon of rainbow colors appearing on a CD or DVD. The surface of these discs has tiny grooves or ridges which act as diffraction gratings. When light hits these grooves, it diffracts and separates into its different colors, creating the rainbow pattern that we see.

In order for diffraction to occur, certain conditions need to be met. The size of the obstacle or aperture must be comparable to the wavelength of the wave. Additionally, the wave must be coherent, meaning that the crests and troughs of the wave are aligned. These conditions allow for the wave to diffract and produce the characteristic patterns and behaviors associated with diffraction.