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Tides. Tides are generated by:. Gravitational pull of the moon and sun Centripetal force of the rotating Earth. Tides are generated by:. the gravitational pull of the moon and sun - moon has 2x greater gravitational pull than the sun
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Tides are generated by: • Gravitational pull of the moon and sun • Centripetal force of the rotating Earth
Tides are generated by: • the gravitational pull of the moon and sun • - moon has 2x greater gravitational pull than the • sun • - sun is 10 million x more massive than the • moon and is 390 times farther away
GRAVITATIONAL FORCE CENTRIPETAL GRAVITATIONAL & CENTRIPETAL
Tidal Cycles • Diurnal Tide: 24 hr 50 min cycle • Semi DiurnalTide: 12 hr 25 min cycle • Mixed Tide: 12 hr 25 min cycle
Description of tides • High water: a water level maximum ("high tide") • Low water: a water level minimum ("low tide") • Tidal range: the difference between high and low tide • Spring Tide: full moon and new moon (14.77 days) • Neap Tide: 1st quarter and 3rd quarter (14.77 days) Intertidal zone High tide Low tide
The monthly tidal cycle(29½ days) • About every 7 days, Earth alternates between: • Spring tide • Alignment of Earth-Moon-Sun system (syzygy) • Lunar and solar bulges constructively interfere • Large tidal range • Neap tide • Earth-Moon-Sun system at right angles (quadrature) • Lunar and solar bulges destructively interfere • Small tidal range
Earth-Moon-Sun positions and the monthly tidal cycle Spring Tide Highest high tide and lowest low tide Neap Tide Moderate tidal range
The Bay of Fundy: Site of the world’s largest tidal range • Tidal energy is focused by shape and shallowness of bay • Maximum spring tidal range in Minas Basin = 17 meters (56 feet)
Alma at High Tide Alma at Low Tide
Inquiry • Which has the greatest tidal effect– sun or moon? • Where is the greatest tidal range located? • Which lunar phase produces moderate tides? • How is a tidal bore created?