WA L1: How do Waves Work Flashcards
How many oceans in the world?
Only one world ocean
Name the ocean basins. (Past and modern)
Arctic, Atlantic, Indian, Pacific, Southern (modern day)
Describe surface currents.
Currents caused by very large scale, permanent winds that blow over the ocean. They transport both matter (water) and energy.
Describe waves. Technical def’n?
Technical def’n: the mechanical expression of energy.
Caused by winds that blow occasionally or over smaller areas. Waves transport energy in the direction of the wave.
What is a crest?
highest point of a wave
What is a trough?
lowest point of a wave
Define wavelength L (or lambda)
distance between two successive crests or two successive troughs of a wave. Unit: meters
Define wave height H
vertical distance between crest and trough (meters)
Define amplitude (a)
vertical distance between crest calm sea level or between trough and calm sea level or half the vertical distance between a crest and a trough; H ÷ 2; (metres)
Define period T
time for one wavelength to pass a point; (minutes or seconds)
Define frequency f
number of waves passing a point per unit of time; (per minute or second)
Define celerity or speed
distance traveled per unit time; (metre per second)
Define steepness
a measure of the “peakedness” of a wave; the ratio of Height to Wavelength, H / L; (no units)
What is the energy transported by waves related to?
related to wave height H; but this only applies to deep-water waves.
Waves with great heights transport more _____ than waves with shorter heights.
energy
Usually, waves with great heights also have long _____.
wavelengths
At any one instance, some wind waves may carry as much or even more energy than waves generated by earthquakes, storms or even the gravitational attraction between the Sun and Earth and the Moon and Earth (tides). So why is the total amount of energy from the disasters much larger compared to wind-driven waves?
wind waves are at one location for very short periods of time (seconds), while larger waves last for longer (minutes, hours, days).
What is generating force?
the force that disturbs the water or causes waves to form
What are the 4 wave types? (GF)
Wind wave, seiche, tsunami, tide
What is the generating force for a wind wave?
wind over ocean
What is the generating force for a seiche?
changes in atmospheric pressure; storm surge; tsunami
What is the generating force for a tsunami?
Faulting of sea floor;
Undersea volcanic eruption;
Landslide into ocean
What is the generating force for a tide?
Gravitational attraction between Earth-Sun and Earth-Moon;
Rotation of Earth
What is the typical wavelength for a wind wave?
60-150m