2007-11-25 23:15:10 · 13 answers · asked by sanjana d 1 in Science & Mathematics ➔ Earth Sciences & Geology
Nearly everyone gets this wrong:
Humid air is actually lighter than dry air.
Reason: Dry air is mostly a mixture of Oxygen (molecular mass 32) and Nitrogen (molecular mass 28). Air contains about one fifth oxygen, four fifthes nitrogen - average mollecular mass about 29.
Humid air (that is, air containing water vapour but not water droplets) contains water vapour, H2O (molecular mass 18).
Molecular mass of water (as a gas) is a lot less than either oxygen or nitrogen, so humid air is LIGHTER.
2007-11-25 23:40:02 · answer #1 · answered by AndrewG 7 · 2⤊ 1⤋
Yes, to most people's surprise, humid air is lighter - and it rises, until it cools in the high atmosphere, and forms clouds, which everybody knows, but they don't connect it. If humid air was denser and didn't rise, there would never be any clouds or rain.
But why?
Ordinary objects can have water added to them without changing their volume, for example cloth. Even wood or stone have pore spaces, which can absorb water to make them heavier without increasing their volume.
But air already is space. To add moisture vapour to it, you have to make room for each water molecule by taking away a molecule of oxygen or nitrogen. And as several good answerers have already explained, the water molecule is lighter than either of these, therefore humid air is lighter.
2007-11-26 01:21:56 · answer #2 · answered by Anonymous · 1⤊ 0⤋
Humid air is lighter than dry air.The reason is given below.
The molecular weight of water vapour is approximately 5/8 th of the mean molecular weight of dry air.This means that the water vapour is lighter than dry air.But a humid air is a mixture of this light water vapour and the dry air.Therfore moist air(humid air) is lighter than dry air in a given volume under identical conditions of temperature and pressure.
2007-11-25 23:52:01 · answer #3 · answered by Arasan 7 · 2⤊ 0⤋
I am going against the crowd and am going to say that humid air is lighter. My reason: Humidity makes the air less dense-you can trust me on this i have studdied it. Hence I guess therefore Humid air is lighter.
2007-11-25 23:29:45 · answer #4 · answered by Anonymous · 2⤊ 0⤋
This Is Only A Guess.....
Humid Air Is Heavier
Because Of The Water Weight?
2007-11-25 23:29:05 · answer #5 · answered by la_nemisis 3 · 0⤊ 3⤋
Dry air is lighter, higher amount of moisture in humid air makes it heavier =)
2007-11-25 23:20:01 · answer #6 · answered by pushplay30 3 · 0⤊ 3⤋
Dry air
2007-11-25 23:18:42 · answer #7 · answered by natrayan1975 3 · 0⤊ 4⤋
dry air!
humid air carries more water vapor with it than dry air. thus humid air is heavier.
teddy boy
2007-11-25 23:22:59 · answer #8 · answered by teddy boy 6 · 0⤊ 3⤋
dry air ,bcz dry air molecules hav more space 2 make it airy n lighter n humid air molecules hav humidity among d space which makes it heavier.
2007-11-25 23:30:19 · answer #9 · answered by beauty 2 · 0⤊ 3⤋
does it make any difference if the humid air is warm or cold?.. either way, id go with dry air.
2007-11-25 23:21:29 · answer #10 · answered by Anonymous · 0⤊ 4⤋