Why the air becomes still?
107764
There is no pressure differential nearby or it is otherwise "contained."  Air flows from high pressure to low pressure to equilibriate.
973898
That is a fantastic question.\nIt is a matter of humidity. The cold weather\nthat allows snow means the air is not humid\nenough to allow an electric current to travel\n(along the water vapor in the air) over the differently\ncharged clouds and sky. People who say temp are\nsort of right, but it is the low temp that leads to the low\nhumidity that causes the "problem".\n\nThanks for asking such a good question.
577442
The water vapor which is released through the combustion of the gases becomes like fog and converts to water droplets when cooled in the air. This is just like the clouds
582102
Air is denser the lower you go on the earth, due to gravity pullin gthe air down. As you move up, there is more "room" for the air to expand. Air temp is just the measure of the net kinetic energy of the molecules of air. The faster and more there are, the hotter it is. therefore, as the air expands as it moves up into the atmosphere, it cools. On top of a mountain, there is less molecules actually hitting your skin, so it feels very cold.
567444
Because it's invisible air has to do something to get noticed.  Hence, air weather events.
1095694
The air around the planet is a viscous fluid and will travel with the rotation of the earth.  This does not take into accounts things such as wind currents or the jet stream which are different things.  There is a little bit of lag in the higher altitudes but its negligible
282253
I'm not quite sure what you are asking here.\nHowever I can tell you that in order for us to remain whole our blood exerts a pressure of 1 atmosphere on our skin to balance that exerted on us by the air around us.
390506
its your body's airconditioner, cool huh1
538503
Because the air is less dense the higher the altitude, there are less molecules available to retain heat. Therefore the heat of the sun dissipates more readily.
518949
maybe "Still Breathing"
803179
Changes in air pressure and possibly humidity.  Your body turns into a barometer.
1163440
because hot air rises and cold air sinks.\n\nit creates pressure changes, which make air particles move rapidly, hence we have wind.
233535
i always thought it was because there was no humidity in the air...probably wrong, anyway. or maybe its because the warm climate doesnt allow the moisture to turn back into water. who knows? prob a weatherman.
803295
The most plausible answer is 3.\n\n- As air expands, it does cool.\n- Cooler air is able to hold less water, so is saturated far quicker.\n- When air is saturated, water droplets will condense out of the air on many available surfaces, including on lenses.
841200
Actually, the air doesn't condense; rather, the water in the air condenses due to the change in pressure. It's the same basic effect as when you change temperature: like when you exhale on a could day and your breathe turns to fog: the decrease in temperature of the air in your breath causes the release and condensation of the moisture in it as a fog. \n\nThe same principle applies to a change in pressure such ias that caused by an airplane's wing. For instance, in an air compressor tank, moisture released by the compression accumulates at the bottom of the tank and has to be periodically drained...
253562
Got to be honest. I became more and more confused about a topic that I used to understand so well with that first response. Although a lot of that is facts, it is overcomplicated at some parts and tough to get a hold on what is actually being described. No disrespect to rizzo though, I realise that everything he wrote is correct so he knows what he's talking about, I just think it would be hard for anyone else to.\n\nMaybe this description will be slightly less dizzying:\n\nAll heat is from the sun. Most of what comes from the sun is short-wave radiation, from 400nm down. Air is not heated very much from the sun, but the ground is. This is because the ground can absorb the short-wave incoming radiation, air cannot (well, only a little bit). The air is mostly heated by the longer-wave radiation that comes from the ground when it gets heated up, which heats the water molecules in the air (that's why humid regions get hotter than dry regions). \n\n*Note: Extremely dry air can be heated too, but that requires continuous exposer to sunlight. As soon as the sun is gone, it gets cold fast. Also it gets colder faster with altitude in dry regions.*\n\nAnyways. Up high, on top of being farther away from the ground, there is also less water molecules to absorb heat (and less molecules total to be heated up at all. So it absorbs less radiation. That is why it is colder. Simple. \n\nNo "adiabatic" mumbo jumbo. But adiabatic cooling is also simple. When air rises, the pressure on it decreases and it expands. The heat will be spread out over more volume, so the air will cool. This is the more complicated reason why the farther away from the ground you get, the colder the air is.\n\nAlso, there is something called an inversion. In this case, the air actually gets hotter as you go up. This happens when a warm air mass is forced up over a denser cold air mass because it is lighter. When this happens, the air is stable (it won't rise). This can result in people getting to choke on their own pollution for a couple of days because the crap they spew up in the air won't rise anymore. It's poetic.
776045
When air is warmed up, its molecules move faster and faster and as a result they move further from each other.  They still have the same mass, but they now occupy a larger volume.  This means that its density is smaller.\nThe opposite when air is cooled off.  The molecules slow down, get closer together, occupy a smaller volume and therefore its density is bigger.\n\nWhen air is warmed up, it goes up.  Once it's up there, is cools off and goes back down.  Near the heated surface the air gets warmed up again, goes up, cools down, goes back down, and again and again.\nThat's called a convection cell.