Wavelength
Topic: Movements of Ocean Water: Waves, Tides and Currents · NCERT: Class 11, Ch 13 "Movements of Ocean Water"
Meaning
Wavelength is the horizontal distance between two crests that come one after the other. Long-wavelength waves, such as swell, are smooth and travel far. Wavelength also decides when a wave breaks. As a wave moves into shallower water, friction with the floor slows it. When the depth falls below about half its wavelength, the wave steepens and breaks as surf.
Example
Long swells reaching the Kerala coast from the far Southern Ocean have long wavelengths. That is why they travel such great distances before breaking on the shore.
Don't confuse with
- Wave period: the time between two crests passing one point. Wavelength is a distance, not a time.
- Wave height: a vertical distance (trough to crest). Wavelength is horizontal (crest to crest).
Related concepts
- Wave
- Orbital motion of water particles
- Fetch
- Wave height
- Swell
- Breaking of waves
- Longshore drift
- Kallakkadal