In osmosis, what happens to the volume of the compartment with low osmolarity as water moves from it?

In osmosis, water moves across a semi-permeable membrane from a region of lower osmolarity (lower concentration of solutes) to a region of higher osmolarity (higher concentration of solutes). This movement occurs in order to balance the concentration of solutes on both sides of the membrane.

As water leaves the compartment with low osmolarity, the volume of that compartment decreases. This is because there are fewer water molecules remaining after some have moved into the more concentrated area. The process continues until equilibrium is reached, where both compartments have similar osmolarity.

Understanding this helps clarify why the volume decreases as water flows out; it's essentially a dynamic equilibrium process seeking to stabilize solute concentrations across the membrane.