The Osmometer Osmotic pressure is the tendency of water to move into a cell.
An osmometer is a device designed to measure osmotic pressure by measuring the amount of internal hydrostatic pressure needed to stop the movement of water into a cell. The osmotic pressure experienced by a cell differs under different environmental conditions. Figure 1. An osmometer. The height of the standing column of liquid in the glass tube provides a way to measure the hydrostatic pressure of the liquid inside the dialysis bag. The higher the column, the greater the internal pressure. The osmotic pressure for different experimental setups is measured as the height of the column after the fluid level has stopped rising. The fluid stops rising when the water pressure inside the bag (the hydrostatic pressure) has increased to the point where it it is equal to the osmotic pressure and stops any more water from moving in.