Final answer:
Reflection causes waves to bounce off a barrier with a potential phase change, while refraction involves a change in direction and speed as waves enter a new medium. Diffraction occurs when waves bend around an obstacle or opening, leading to patterns of interference.
Step-by-step explanation:
Reflection, Refraction, and Diffraction of Waves
Waves behave differently when they encounter new media or obstacles. During reflection, a wave bounces back into the original medium after hitting a barrier. Reflection involves a change in direction and may cause a phase change, such as a 180° inversion where the wave flips vertically; this means a crest becomes a trough and vice versa.
Refraction occurs when a wave passes from one medium into another, causing a change in speed and direction due to differing indices of refraction. The direction changes toward the normal (the perpendicular to the interface) when entering a medium with a higher index of refraction and away from the normal when entering a medium with a lower index.
Diffraction happens when waves bend around the edges of an obstacle or pass through an opening. This bending allows waves to spread out and it depends on the size of the obstacle or opening in relation to the wavelength of the wave. Interference patterns can result from diffraction, where waves can overlap to cause constructive (increased amplitude) or destructive (decreased amplitude) interference.