If hot air rises, then why is the air so cold up there?

Question

Like above the clouds and at the top of mountains...

Answer 1

Because where we are there is a lot of hot air to rise - ie a bigger concentration of hot air. The higher you go, the more the warm air has dispersed into the atmosphere and cooled down by the colder atmosphere.

Answer 2

It's like this: the sun heats the earth (sun's radiation passes through the air unaffecting it), the earth and everything on it heats the air which rises up. On the other hand temperature around earth (in space) is around 2 degrees K (or -456 F) and that cools the air in the outer layers of the atmosphere. So the hot air rising up gets cooled down as soon as it rises high enough, (depending on the weather).

Answer 3

Hot air rises. That is true. Then what happens to the hot air?
Hot air rises because it has a lower density than its surrounding air. Not because it is hot, but because it has higher volume per unit mass.
It does not stay hot as it rises! The heat quickly dissipates into the surrounding air from that orginal volume of hot air, until there is thermal equilibrium, which would also make the surrounding air of equal density!

Air up there, exists because it simply does, due to gravity.

Not because heated air rises up there!

However, the further away from earth, the thinner the atmosphere.

So less air is up there, the air up there is very thin, so it is colder since the there is lesser mass of air to store and transfer heat. Less air, less heat capacity per unit volume! Less air to trap heat!

Also, take into account that heat is radiated from earth's surface, so the further away from the surface, the cooler it gets. Though the main reason is still the thinning of the atmosphere as it gets higher up there!

Answer 4

The air cools as it rises. The earth is warm, the air warms up when it is close to the earth, it rises, and cools, and then sinks down again. It is an active process. Warm air can hold more water than cold air, so the rising air carries up water vapour with it. When it cools the water precipitates out and falls as dew or frost, rain or snow. This is very fortunate for us and other living beings on earth.

Answer 5

I suspect it's a pressure thing. As you rise, air pressure lowers. Pressure, volume and temperature are all related, so a drop in pressure means a corresponding drop in temperature.
Interestingly, this only happens up to a point. Air temperature in the upper atmosphere (ionosphere sort of way, 80+ Km) is actually quite high during the daytime, 1000+degrees. This is due to the massive amount of energy it receives from the sun; the atmosphere shields us from the worst of the sun's rays (and that's why we don't use CFCs in aerosol cans any more). So, it's a balance between dropping pressure and increasing thrmal radiation.

Answer 6

Fundamentally, temperature measurements are the ability of a medium to exchange energy with the recieving thermometre. So the temperature that you read off a thermometre is influenced by the number of collisions, hence energy transfer between air molecules and the thermomtre's surface. You need high concentrations of molecules to measure air temperature.

So as you climb a mountain it gets colder, but not because the molecules are not hot, but because there are fewer of them. This means less collisions with your skin so less exchange of temperature from the air to your skin.

However, to get an accurate reading of the real temperature of air molecules, these need to be studied using vibrational laser spectroscopy. It measures the excitation levels of molecules, and hence determines how much energy they have. If molecules from high up in the atmosphere were to be down at our level we would fry. But because there are so few molecules higher up, there is a lower probablilty of encountering these, hence lower heat exchange rate, so it ultimately feels cooler.

The reason why the air molecules at sea level have so much less energy than those near space is because most of the energy is absorbed or reflected away before it get to our level. On top of this the energy that does get to our level gets distributed between infinitely more molecules than at high altitudes.

As previously said by one of the other contributors, its all down to air density and incoming radiation levels.

Answer 7

all your solutions so some distance are incorrect. warm air does certainly upward push. Why does this ensue? nicely, its through fact the stress interior the ambience falls as you benefit altitude (through fact there is way less environment over your head pushing down); the nice and comfortable air is way less dense than that around it, so this stress gradient supplies upward push to a internet stress pushing up on the nice and comfortable air. yet through fact the nice and comfortable air rises it stories that decrease stress. And so it expands. From the gas rules you will understand that if a persevering with mass of gas expands with none potential enter it cools down. Utlimately it is going to quiet down sufficient that it now not rises. What this implies is that air is needless to say cooler the better you bypass. the ambience is in a stable equilibrium whilst the replace in temperature as you upward push is exactly what's mandatory to end pocket of warm air growing to be. it rather is named the adiabatic lapse cost, and it rather is approximately 0.sixty 5 C in keeping with 100m. So in case you bypass up a 1000m mountain the actual is 6.5C cooler than the backside. in case you bypass as much as ten,000m in a airplane it rather is sixty 5 C cooler (the exterior of a airplane is often around -50C).

Answer 8

Hot air expands the further it rises, releasing latent heat to cope with the pressure changes.

Answer 9

vos there's so much air there that any air warmed artificially on earth is a mere drop in the proverbial ocean

Answer 10

It losses heat as it rises.