Quote:Higher altitudes are colder because of the air pressure. It's the same properties that cause CO₂cartridges to become colder as you release the pressurized gas. At 20,000 feet above sea level the air pressure is 6.4 PSI which is less than half of the air pressure at sea level (14.7 PSI).

 

I was taught that the cylinder becoming colder is due to the Ideal Gas Law behvior since the Volume of the container remains the same, and the temperature is dependent on the pressure drop.

 

Essentially; since T₂= T₁ x (P₂/P₁) if we state that T₂ is the final temperature of the gas, then as the pressure drops -- or P₂ gets smaller -- then the value which we multiply T₁ by gets smaller, therefore reducing the value of T₂, lowering the temperature.

 

At first, I thought your statement was wrong and that the reason that it's colder at higher altitudes is because of a thinner layer of air insulation. But I was wrong. Since the pressure on the air at higher levels is lower, as you stated, then the air is expanding. Since the air is expanding it is doing work. Work is heat so that means that the air gets cooler as it expands.

 

Yeah! Science y'all!!!!

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