[thewax]

NOTE: This is NOT a homework question. This is just a question I stumbled upon as I was trying to understand the text.

We know that gas flows from a region of higher pressure to a region of lower pressure (a very important concept in the mammarian breathing mechanism). WHY does this happen?

I guess my confusion stems from the fact that (according to my book) the property above and diffusion are totally different things, as evident in transpiration. Diffusion would take forever, but thanks to transpirational pull ( which utilizes the property above), transpiration does not a decade to bring a water molecule up the stem. But I can't think of anything else either than diffusion's mechanism that would explain how the property that gas flows from a region of higher pressure to a region of lower pressure works. Please *delete me*!!!

I thank you in advance.

[Borek]

We know that gas flows from a region of higher pressure to a region of lower pressure (a very important concept in the mammarian breathing mechanism). WHY does this happen?

If you have a cylinder with movable piston inside, and pressures on both sides of the cylinder are different, what is a net force acting on the cylinder? Which direction does it push the piston? When will the force become zero?

When there is no pistion, equilibrium condition is identical.

[lancenti]

but thanks to transpirational pull ( which utilizes the property above), transpiration does not a decade to bring a water molecule up the stem.

Don't forget capillary action.

But the physical equation that describes pressure in terms of force and area might help. Then consider the particle between the two 'pressure walls'