🚀 go-pugleaf

John wrote:

>  know that it is counter-intuitive to think that the water would not
> move from a higher pressure to a lower pressure, but what you have to
> consider is the partial pressure of water on each side of the membrane.
> (I am borrowing the concepts from gasses, a chemist would probably be
> able to come up with a more accurate analysis.) Think about what would
> happen if you had low pressure water on one side of the membrane and
> high pressure methanol on the other, and the membrane is impervious to
> the methanol. Water inside the membrane can diffuse in both directions,
> and would equilibrate only when as much is diffusing in one direction as
> the other. This means that the water would diffuse from the low pressure
> side into the high pressure side (and dissolve into the methanol). It
> would only stop when as much water is coming out of the methanol/water
> solution as is going in.


It is interesting to compare to the human body's nervous systems' firing
of membrane potentials: only when the concentrations on each side of the
nerve cell membranes are *in* equilibrium will the gates open to flows
across the membranes.

-lozang