What is diffraction in waves and how does it affect the propagation of light and sound?

Diffraction is the bending of waves around obstacles or through openings. In the context of light and sound, diffraction causes waves to spread out and change direction when they encounter obstacles or pass through small openings. This affects the propagation of light and sound by causing them to diffract, or spread out, which can impact how they are perceived and interact with their surroundings.