Why is it the higher up you go, the colder it becomes?

Question

I was in a flight a while back, and saw a temperature reading on those little TV screens and wondered why it is that up in the sky, it is colder, but that hot air rises?

Because in Southern California, it is pretty hot on the ground. Shouldn't it be cold?

Answer 1

There are several reasons.

First the air doesn't absorb sunlight very effectively, whereas the gorund does. Then the air near the ground gets heated by the infrared light emitted by the heated ground. The air molecules then rise, and collide with the less energetic molecules and thus cool and sink back down.

So the further from the groun you are, the less effective is the heating.

The other issue is that air only rises as far as the top of the troposphere, bottom of the stratosphere. So if you are in very high flying plane you are above the section of the atmosphere in which hot air rises.

Answer 2

heat is actually trillions of molecles buzzing around - the hotter it is when these are buzzinga round faster and faster - warmed up by the sun... if there are no molecules around to warm up then there is not much moving and so as you go higher up there is less air - for example, at 30,000 ft you need an oxygen cylinder to keep going (Everest is that high) and if you go higher there is less air so less molecules to warm up and even though you are nearer the sun, it gets colder... so when you get to outer space to a vaccum, it is MINUS 273 degrees centigrade - thats cold....

Now this is lucky as the sun can only warm stuff up once, if there were stuff out there at 30000 feet to be warmed there woudl be less warmth left at ground level....