Difference Between Hydrostatic And Osmotic Pressure

What Is Hydrostatic Pressure?

Hydrostatic pressure is the pressure that is exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity. Hydrostatic pressure increase in proportion to depth measured from the surface because of the increasing weight of fluid exerting downward force from above.

What You Need To Know About Hydrostatic Pressure

• Hydrostatic pressure depends on gravity.
• Hydrostatic pressure can be present in any fluid that is static i.e not moving.
• Hydrostatic pressure can occur in a pure fluid or any fluid with any level of concentration.
• Hydrostatic pressure is greatly influenced the density of the fluid in which it is being measured, atmospheric pressure, acceleration due to gravity and the level of fluid above the point of measurement.
• In the body, the hydrostatic pressure drives the material out of the capillary.
• Hydrostatic pressure is different in different levels of the same liquid.
• In hydrostatic pressure a semi-permeable membrane is not involved.

What Is Osmotic Pressure?

Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semi-permeable membrane. It is also defined as the measure of the tendency of a solution to take in pure solvent by osmosis.

Osmotic pressure reduces water potential which is the tendency of water moving from one area to another. Thus, it is necessary in plant cells for turgidity and support.

What You Need To Know About Osmotic Pressure

• Osmotic pressure depends on interaction between liquid and solid.
• Osmotic pressure can only be present in special systems in which there are different concentrations of a fluid (solution and solvent) that are separated by a semi-permeable membrane.
• Osmotic pressure cannot be present in a solution with equal concentration. There have to be two solutions with unequal levels of concentration.
• Osmotic pressure is greatly influenced by the adhesion (electrostatic forces) between the liquid (water or other) and some solid lattice, like a semi-permeable membrane.
• The osmotic pressure brings the material back to the capillary.
• Osmotic pressure is the same everywhere of the liquid, thus it is calculated considering the whole system. 
• In osmotic pressure, a semi-permeable membrane is involved.

Also Read: Difference Between Diffusion And Osmosis

Difference Between Hydrostatic And Osmotic Pressure In Tabular Form