Wind

[Ads]

What is wind, and where does it come from? And, indeed, where does it go to?

[fly258]

Wind is air moving from a high pressure area to a low pressure area

[gazzawazza]

Just to explain a little bit more, (and I really hope I'm not being patronising here), wherever you get an area of high pressure (liquids or gases) it will always try to equalise so that all area have the same pressure.

Two examples I can give are; a) Imagine two large vessels connected by pipework. One is full of water, the other almost empty, but the valve between the two is closed. Now imagine when you open the valve water will flow from the full tank until it levels out and the pressure is equal throughout the system.

b) Now think of a ballon full of air. The air inside the balloon is at a greater pressure than that outside which is at atmospheric pressure. If you let go of the balloon neck the air will rush out until the balloon is flat. The pressure has equalised. So as fly258 says, wind is air moving from an area of high pressure to low pressure.

[Ads]

Thanks for that - it makes sense. But why does wind 'gust'? Using your vessels analogy, why doesn't the wind just flow from A to B? Why does it get whipped up into storms?

[bernardo]

The reason why it doesn't just decide where it wants to be and then go there and stop is because there are external forces working on the air to make the pressure change - e.g. the sun heats the ground, the ground heats the air, the air rises, and it sucks in air from around to fill the gap. If the forces are strong enough, it might end up swirling round in a tornado or hurricane (like the water forming a whirlpool going down the plughole of a bath). The swirly gusty bits are just very small tornadoey things.

[gazzawazza]

Yes, as bernardo says, the swirly gusty bits are just very small tornadoey things. If you put some water in the bath, let it settle then swish your hand from one end to the other you can see that along the "wake" of your hand there are little eddies. The same happens with wind, the main stream blows and all along it's length there are "whirlpools" of wind created.

[sft42]

I can't believe that no one has interjected with a fart joke yet!

What a great opening for something along the lines of a build up of gas pressure in the guts and it seems to go straight to the nose......ah well nevermind.

[Dave Potts]

I can't believe it either. It's a relief to me and a torment for others, it comes from eating too many beans, cabbage and sprouts, and I find mine disperses nicely sub-duvet, if I lie very still. There.

[Ninereeds]

hmm, it does explain a lot but why does the how and low pressure points occccur in the air so that win can move, if its just open space surely after all this wind for what? 40 billion years everything should have equalised?

[Ninereeds]

*high and low sorry