What materials, for use in a filter, would let air pass throught it but not water, or other liquids?

Answer 1

A liquid filter, where the liquid is the filter it self, an air washer

Answer 2

Easy. Do you know how your trap in your toilet works. You want something like that but... just the opposite.

Im thinking something along the lines of having a sideways "T" where the top of the t is rotated clockwise 90 degrees. And so the horizontal part of youre "T" is the input. And as watter would come through, it would fall through the bottom of the vertical part of the "T" and only the gasses would be able to come out the top part of your "T". Now this assumes that teh gass is less dense then air but even if not, if you put a vacuum on it then the negative air pressure will suck the gas.

Or you could use a wet-dry vac? And just have the suck part be the input and where it blows out the air be your filtered output.

Answer 3

I'm no scientist but i believe any material that is porous and non absorbent would let air pass but not water. Air molecules is smaller than water molecules so any materials would pores that has smaller pores for air to pass but not water do so.

Answer 4

you need a filter with holes larger than the size of an air molecule but smaller than a drop of water or drop of other liquid? example:
gore-tex lets water vapor pass through but won't let rain (water drops) pass. a molecule of water vapor is much smaller than a drop of water.

good luck!

Answer 5

Paul W, beat me to it. Goretex.