tides text book page # 366 - 371 tides the daily rise and fall of earth’s water on its coastlines...
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TidesTides
Text Book Page # 366 - 371 Text Book Page # 366 - 371
TidesTides•The daily rise and fall of Earth’s water The daily rise and fall of Earth’s water
on its coastlines is called a on its coastlines is called a tidetide..
•Caused by the interaction of Earth, the Caused by the interaction of Earth, the moon and the sun.moon and the sun.
•Tidal rangeTidal range is the is the difference in ocean difference in ocean levellevel between high-tide and low-tide. between high-tide and low-tide.
Gravitational Effect of the Gravitational Effect of the MoonMoon
•Two big bulges Two big bulges (Tidal) (Tidal) of water of water form on the Earth:form on the Earth:– one directly under the moon one directly under the moon (due (due
to gravity) to gravity) – another on the exact opposite side another on the exact opposite side
(due to inertia) (due to inertia)
•As the Earth spins, the bulges As the Earth spins, the bulges follow the moon.follow the moon.
The Daily Tide CycleThe Daily Tide Cycle•One low-tide and high-tide cycle takes One low-tide and high-tide cycle takes
about 12 hours and 25 minutes.about 12 hours and 25 minutes.
Gravity and TidesGravity and Tides
Low Tide
Low Tide
High Tide
High Tide
The Monthly Tide Cycle
•The changes in the position of The changes in the position of Earth, the moon, and the sun Earth, the moon, and the sun affect the heights of the tides affect the heights of the tides during a month. during a month.
Spring TidesSpring Tides
Twice a month, at the new Twice a month, at the new moon and the full moon, the moon and the full moon, the earth, the sun and the moon earth, the sun and the moon lined up.lined up.
High Tides are higher and Low High Tides are higher and Low Tides are lower than normal. Tides are lower than normal.
Tidal range is maximum.Tidal range is maximum.
Spring TidesSpring Tides
Neap TidesNeap Tides At the first and third quarters At the first and third quarters
the earth, the sun and the moon the earth, the sun and the moon pull at right angles to each other.pull at right angles to each other.
High Tides are lower and Low High Tides are lower and Low Tides are higher than normal.Tides are higher than normal.
Tidal range is least.Tidal range is least.
During new and full moon phases the moon, sun, and Earth are aligned causing a greater gravitational pull on the Earth. This results
in higher high tides and lower low tides.
At the first and third quarters the earth, the sun and the moon pull at right angles to each other.
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Tidal Energy – The Energy from Tidal Energy – The Energy from TidesTides Clean, renewable source of Clean, renewable source of
energy.energy.
Harnessing tidal energy only Harnessing tidal energy only possible when tidal range is at least possible when tidal range is at least 4 or 5 meters. 4 or 5 meters.
Very few locations are suitable for Very few locations are suitable for tidal power plants.tidal power plants.
The EndThe End