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Author Topic: Where does wind come from?  (Read 8293 times)

Offline Hadrian

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Where does wind come from?
« on: 31/03/2006 18:28:01 »
What blows and how?

What you do speaks so loudly that I cannot hear what you say.


 

Offline neilep

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Re: Where does wind come from?
« Reply #1 on: 31/03/2006 18:44:31 »
I used to think the wind was caused by the world spinning faster that day [:I] I was much younger then, about 34. :)

I know we've covered this before, if I can find the link I'll post it here which of course will not hinder further posts.

It's all to do with air pressure and temperature and stuff !!..

There ! glad I'm still on my cerebral streak.

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Offline daveshorts

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Re: Where does wind come from?
« Reply #2 on: 31/03/2006 19:25:54 »
Wind is driven by temperature differences, the most simple case is a convection cell - air rises over a hot place and therefore sucks more air in from the sides, causing wind.

 Like an ice skater speeding up as she pulls her arms in air on a spinning planet will tend to spin up as it moves in towards where it is rising, hence why wind tends to circle around a low pressure area (the low pressure being caused by air rising).
 

Offline JimBob

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Re: Where does wind come from?
« Reply #3 on: 01/04/2006 23:21:31 »
Actually, it isn't temperature. It is parastolic action.

The mind is like a parachute. It works best when open.  -- A. Einstein
 

Offline Andrew K Fletcher

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Re: Where does wind come from?
« Reply #4 on: 06/04/2006 12:53:19 »
We have warm air rising and colder air falling within desert regions known as the Hadley Cell, this recycles the hot dry air of the Sahara desert towards the centre of Africa, where the air cools and falls back to the ground, predominantly at night. Parts of Africa are notoriously prone to rainfall during the evening. Wind is an inevitable consequence of air circulating in this way. The same can be said for the Polar Cell and the Ferrel Cell, each contributing to global winds and weather patterns. However this still does not explain what causes wind.

The Atlantic conveyor system, which is thought to drive the World’s weather along with the ocean currents brings the main clue, the circulating waters of the oceans are known to distribute warm water around Northern Europe and return colder water to the Equatorial regions. But it is not heat that drives the Atlantic Conveyor, it is a simple process of evaporation of pure water from the surface of the ocean around the colder Northern Arctic Regions and again the same process around the Antarctic Regions. The resulting denser surface sea water sinks rapidly causing warmer water to be pulled from the Equatorial waters generating the temperature changes required to stimulate rainfall and winds. It is believed that the last ice age was caused when a fresh water Lake called Agaziz was released by warmer temperatures melting the ice that held it in place, causing it to flow down the St Lawrence River into the oceans and turning the surface water of the oceans into less salty water. This then prevented the evaporation from having a significant concentrating effect on the sea water and caused the Atlantic conveyor system to stop. This had devastating effects on the world’s weather, as the warmer equatorial waters and air could not be drawn out to address the freezing weather from the North polar regions and the inevitable ice age began. Apparently it only took 70 years from the time the fresh water entered the oceans.

Now, this leaves us with a scary situation as it is now known that countless billions of cubic metres of fresh salt free water are pouring into the oceans once again, caused by global warming and rapidly melting ice caps.

Does this mean that we are heading for some serious weather changes in the not too distant future?

Andrew





"The explanation requiring the fewest assumptions is most likely to be correct."
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Offline Hadrian

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Re: Where does wind come from?
« Reply #5 on: 06/04/2006 20:39:22 »
It is interesting how we all assume that what we believe the words we hear or read are what people mean. I could have been asking where wind in the body comes from. Language is can lead to misunderstanding so easily. We think we know what others are saying when often we don’t.      

What you do speaks so loudly that I cannot hear what you say.
 

Offline Karen W.

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Re: Where does wind come from?
« Reply #6 on: 27/07/2006 15:55:12 »
Do any of you know some cool science experiment that could demonstrate this theory to a group of 3 to 5 year olds? If you do please let me know, as I would be interested in teaching the experiment to my class it to my class?..........Karen
 

Offline crandles

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Re: Where does wind come from?
« Reply #7 on: 29/07/2006 23:29:17 »
quote:

Like an ice skater speeding up as she pulls her arms in air on a spinning planet will tend to spin up as it moves in towards where it is rising, hence why wind tends to circle around a low pressure area (the low pressure being caused by air rising).



That may be true of hurricanes and tornadoes but it I don't think it is the cause of 'wind tends to circle around a low pressure area'. That is mainly the coriollis force.
http://en.wikipedia.org/wiki/Coriolis_Effect#Coriolis_in_Meteorology
 

Offline Karen W.

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Re: Where does wind come from?
« Reply #8 on: 27/07/2006 15:55:12 »
Do any of you know some cool science experiment that could demonstrate this theory to a group of 3 to 5 year olds? If you do please let me know, as I would be interested in teaching the experiment to my class it to my class?..........Karen
 

Offline crandles

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Re: Where does wind come from?
« Reply #9 on: 29/07/2006 23:29:17 »
quote:

Like an ice skater speeding up as she pulls her arms in air on a spinning planet will tend to spin up as it moves in towards where it is rising, hence why wind tends to circle around a low pressure area (the low pressure being caused by air rising).



That may be true of hurricanes and tornadoes but it I don't think it is the cause of 'wind tends to circle around a low pressure area'. That is mainly the coriollis force.
http://en.wikipedia.org/wiki/Coriolis_Effect#Coriolis_in_Meteorology
 

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Re: Where does wind come from?
« Reply #9 on: 29/07/2006 23:29:17 »

 

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