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Author Topic: Why the water on Earth does not swirl?  (Read 2317 times)

Offline Astronomer_FB

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Why the water on Earth does not swirl?
« on: 12/02/2009 12:01:38 »
Hi I was wondering why the water on earth is not in a swirling pattern.  If you were to take a cup of water and start to rotate the cup the water inside would start to swirl, why does this not happen on earth since it is rotating so fast.


 

Offline Vern

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Why the water on Earth does not swirl?
« Reply #1 on: 12/02/2009 12:11:25 »
I think that water does swirl due to earth's spin. Ocean currents moving from the equator toward the north tend to follow westward land masses and move up the coast line. Water only needs to swirl when it must move perpendicular to the spin axis.
« Last Edit: 12/02/2009 12:13:24 by Vern »
 

Offline dentstudent

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Why the water on Earth does not swirl?
« Reply #2 on: 12/02/2009 12:12:42 »
The Coriolis Effect.
 

Offline Astronomer_FB

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Why the water on Earth does not swirl?
« Reply #3 on: 12/02/2009 13:06:32 »
The Coriolis Effect.
Thank you that helps alot I just looked up what it is and it makes sense now why.
 

Offline dentstudent

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Why the water on Earth does not swirl?
« Reply #4 on: 12/02/2009 13:16:15 »
You're welcome!
 

Offline chris

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Why the water on Earth does not swirl?
« Reply #5 on: 12/02/2009 13:40:07 »
The bottom line is that for the water to be swirling there must be a force acting upon it. Where would such a force come from. You'd only see swirling water if the Earth abruptly stopped turning, but the water were allowed to continue moving. Then the inertia of the moving body of water would keep it spinning.

Chris
 

Offline Vern

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Why the water on Earth does not swirl?
« Reply #6 on: 12/02/2009 15:31:06 »
Quote from: chris
You'd only see swirling water if the Earth abruptly stopped turning, but the water were allowed to continue moving. Then the inertia of the moving body of water would keep it spinning
I agree that there must be a force acting upon it. The force can come from the rotation of the earth.

The equator of the spinning earth is rotating so that it moves at about a thousand miles per hour. The poles are at zero miles per hour. When anything moves toward the poles from toward the equator, that thing wants to continue moving at its previous speed.

I suspect that is what causes the swirling.

Quote from: Wikki
Perhaps the most commonly encountered rotating reference frame is the Earth. Moving objects on the surface of the Earth experience a Coriolis force, and appear to veer to the right in the northern hemisphere, and to the left in the southern. Movements of air in the atmosphere and water in the ocean are notable examples of this behavior: rather than flowing directly from areas of high pressure to low pressure, as they would on a non-rotating planet, winds and currents tend to flow to the right of this direction north of the equator, and to the left of this direction south of the equator. This effect is responsible for the rotation of large cyclones (see Coriolis effects in meteorology).
« Last Edit: 12/02/2009 15:48:42 by Vern »
 

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Why the water on Earth does not swirl?
« Reply #6 on: 12/02/2009 15:31:06 »

 

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