Afternoon all

Walking to this pub this dinner time and one of those conversations struck up which left everyone scratching their heads. As this forum contains some highly intelligent people I thought I'd ask here for an answer.

One of the people walking to the pub is considerably shorter than me, I joked that it must be warmer "down there" as there was no mist showing when she breathed. She retorted that warm air rises so it sohuld be warmer around my head than hers! touche (1-0)

Thing is if warm air rises and the only thing heating the air is the sun shouldn't the air keep getting warmer the higher up you get? so shouldn't it be warmer at the top of Everset than the bottom?

Simple explaination as to why it's colder at altitude such as in a plane when you're in air nearer the sun please?

Is it not something to do with the higher you are the thinner the air. So there's less air to get warmed in the first place. Maybe?

Hmmm I think the sun heats the ground more than it heats the air itself (track temps are normally hotter than air temps in motor sport, right?), so the ground in turn must heat the air closest to it most. Probably.

Probably more to do with the air getting thinner with altitude as above though.

With the air being warmer though wouldn't there be more air rather than less as the hot air should all be rising?

(edit)before everyone thinks I'm a complete muppet I realise that air does get thinner as you get higher but if you follow the rule that hot air rises and it's herated by the sun why is there less air high up?

[Edited on 7/12/10 by jabbahutt]

The air gets heated at ground level from the earth or water warming from the suns rays. The air doesn't heat up as the suns rays pass through it. So the air at the surface warms up and the molecules move faster, so the same volume of air will have less molecules in it as they are moving faster, so this air is less dense and moves upwards (hence a hot air balloon rises on a cold clear day). As it moves up it gradually cools down.

sorry i copied it but says it better than i would

DRY ADIABATIC LAPSE RATE.—If a parcel of air is lifted, its pressure is DECREASED, since pressure decreases with height, and its temperature falls due to the expansion. If the air is dry and the process is adiabatic, the rate of temperature fall is 1°C per 100 meters of lift (10°C per Kin), or 5 l/2°F per 1,000 feet of lift. If that parcel descends again to higher pressure, its temperature then INCREASES at the rate of 1°C per 100 meters or 5 1/2°F per 1,000 feet. This is known as the dry adiabatic lapse rate.

so you can calculate the dif in temp between heights

Cheers all, trust me that is was a tongue in cheek question rather than serious. These things keep cropping up in the pub, must reduce beer intake during dinner times