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Geography
Coasts
Question | Answer |
---|---|
Define ‘wavelength’. | The distance between two successive wave crests (or wave troughs) |
Define ‘wave height’. | This is the vertical height between the trough and the crest of a wave. |
What provides waves with energy? | The wind, as it blows across the sea’s surface |
What three parameters control how much energy a wave gains? | 1. Windspeed 2. Duration of windy conditions 3. The distance over which wind and water are in contact (the fetch) |
Why does particle motion within a wave change as the wave approaches the shore? | Particle motion in waves is limited to a depth of one wavelength. When the seabed is at less than one wavelength depth, the presence of the seabed changes the motion of water moving in the wave, creating a more elliptical particle motion. |
What effect does this have on the following? 1. Wavelength 2. Wave height 3. Wave steepness | 1. The wavelength is reduced. 2. The wave height increases. 3. The wave becomes steeper. |
What are the swash and backwash? | Swash: Water that rushes up the beach in an onshore direction after a wave breaks. Backwash: Water running back down the beach in an offshore direction due to the pull of gravity. |