chapter iii waves and tides
DESCRIPTION
Wave Parts Waves are driven by wind Crest Trough Size = wave height = vertical distance between trough and crest Distance between waves (wavelength) = period = time it takes the wave to go by a pointTRANSCRIPT
Chapter IIIWaves and Tides
Wave Parts•Waves are driven by wind•Crest•Trough•Size = wave height = vertical
distance between trough and crest•Distance between waves
(wavelength) = period = time it takes the wave to go by a point
Wave Movement•Water particles don’t have any net
movement•Crest move up and forward•Trough move down and back•Carries energy
Formation of Waves
• Wind forms waves
• Fetch = span of open water over which the wind blows
• Swells form in open ocean
• Cancellation = crest and trough meet and average out
• Reinforcement = crest and crest meet and produce a bigger wave
Breaking Waves•In shallow water waves:
•Slow down•Get higher•Get closer together•Break when get too steep and
unstable
Tides• Tides = rhythmic
rising and falling of water caused by the gravitational pull of the sun and moon• Moon has a
stronger pull because it is closer
Gravitational Pull• Moon pulls water towards it
• Bulge on that side of earth• Bulge on opposite side of earth because
of centrifugal force• Earth rotates under the bulge to get high
and low tides• Sun does the same thing, but weaker
• Can have additive impacts
Timing of the tides
•2 high tides, 2 low tides every 24 hrs and 50 min•50 min accounts for the moon’s
movement
Tidal Range• Tidal Range = difference in water level between successive high and low tides• Spring tide = large (sun and moon in
line)• Neap tide = small (sun and moon at
odds)
Tide Types• Number of tides
• Semidiurnal tides = 2 high, 2 low (N. America, Europe, Africa)
• Mixed semidiurnal tides = 2 high, 2 low but of different ranges (West coast of N. America)
• Diurnal tides = 1 high, 1 low (Antarctica, Caribbean, Canada
Tide Types
Tide Tables
•freetidetables.com