Why is wind cold? If wind is the moving of air molecules wouldn't

Sunlight mostly passes through the air, and warms the ground instead. Additionally, the inside of our earth is much hotter than outer space, but i think the crust insulates most of that heat anyway

The "movingness" of the air molecules is irrelevant because the ground's molecules are moving even more, this is already reflected in the temperature, NOT the wind speed.

So air is typically colder than the ground.

Wind feels even colder than static air because of convection. The quick,moving air just increase the thermal transfer rate

http://scienceblogs.com/principles/2010/08/17/wind-and-temperature-why-doesn/

>The full answer to this involves a couple of subtle issues, but I like to start with a simple-but-cool fact, which is that the speed of wind just isn’t that big a change in the speed of an air molecule.

> you find that the rms average speed of a molecule of a nitrogen molecule in air is a bit more than 500 m/s. For reference, the speed of sound in air is around 330 m/s, so any given nitrogen molecule in the air you’re breathing is moving significantly faster than the speed of sound.

>That means that wind can barely make a difference in the temperature. Hurricane-force winds have a speed of around 50 m/s,

>There’s also a more subtle issue here having to do with the fact that temperature is associated with random motion, not collective motion of the whole thing. A bottle of air in a jet aircraft is not “hotter” when the plane is flying than when it’s sitting on the tarmac, just because the container is moving. The same goes for any random bit of air– if the whole mass of air is moving to the west at 3 m/s, that doesn’t change the temperature.


Maximal spoonfeeding, try Google next time.

>>7766609

I don't even know where to begin.

>>7766584
evaporation as well, the most heated water molecules are the ones to vaporize first, displacing them leaving your skin cooler

You can heat a cup of coffee by stirring it, but it would take a long time and you would have to stir very hard.

It's weird, right? The small scale movement represents so much more energy. Those little air molecules are moving around 1000 miles per hour each but it's all disorganized.

File: air1.gif (54KB, 420x400px) Image search: [Google]

54KB, 420x400px

>>7766623
well I guess in the thermosphere it actually gets pretty warm

>>7766618

I'd also like to say that the last point there is probably the most important one. We can choose an arbitary reference frame and clearly just choosing a reference frame centered at the sun doesn't mean the gas is now hotter because it moves with the Earth.

The motion of the particles relative to each other (bit of an awkward wording, but oh well) is what matters, since that will always give the same magnitudes of the relative velocities. Generally, if you have a lump of particles we choose a frame such that their center of mass doesn't move to make things easier.

Wind means the motion of the group of particles, but it does not affect the motion of the particles relative to each other, so it doesn't increase their temperature.

>>7766609
Considering your last point/ would high winds at 100 degrees feel even hotter than 100 degrees much like the opposite effect of wind chill since body temp is lower than 100 degrees?

>>7766656

Yes, you can try for yourself in a sauna. Although there's some other stuff going on there, too (namely a small air bubble forming around you that's cooler than the other air).

>>7766656
Well we cool by evaporation, so a slight breeze might actually cool you off by making evaporation more effective, but it could theoretically get worse if the wind speed is high, think convection oven.

But in normal conditions, for hot conditions relative humidity has a larger affect, so the "heat index" is typically given which accounts for humidity instead of wind speed.