ZingPath: Reflection and Refraction

Water waves are characterized by their height, wavelength, period and propagation velocity. Wave height is the distance between the trough and the crest; the trough is the lowest point of a wave, and the crest is the highest point. Wavelength is the difference between two crests. Wave period is the time it takes for two consecutive crests to pass the same point, and propagation velocity is the speed at which a wave travels through a particular medium.

Wavelength and velocity are directly proportional-as velocity increases, wavelength increases, and as velocity decreases, wavelength decreases. Wavelength and velocity vary depending on the depth of the water. Wavelengths decrease as waves move from deep to shallow water, as does velocity since they are directly proportional. Conversely, when wavelengths increase as waves move from shallow to deep water, velocity also increases.

Refraction of water waves is the bending of waves due to changes in wave velocity caused by varying water depths underneath. The part of the wave in shallow water will move slower than the part of the wave in deeper water. Therefore, when the depth of water varies under the crest, the wave bends and water wave refraction occurs.