# Hydrostatic Pressure vs. Osmotic Pressure

From the word of the Hydrostatic pressure, we mean the pressure that is experienced by a point present inside the fluid. The osmotic pressure, on the other hand, is the pressure required for stopping the fluid transfer of a semi permeable membrane. You need to apply the osmotic pressure in order to prevent the movement of a fluid in a semi permeable membrane. The movement of the fluid becomes possible due to the different levels of concentrations present between the two solutions, commonly known as the solute and the solvent. The appearance of the Osmotic pressure becomes possible at the time when the two solutions are separated with the help of a membrane. The function of this membrane is to allow the solvent to pass through it, but at the same time, the solute is not given the permission to do so. The Hydrostatic pressure is a specific type of pressure that is implemented on any point on a liquid which is at rest. The calculation of the pressure at that point is very simple as it is equivalent to the weight of the column of fluid which is present directly above that point. This is the main cause that the hydrostatic pressure is greatly subjective to the density of the fluid in which the pressure is being measured. The hydrostatic pressure is depended upon the atmospheric pressure, acceleration due to gravity, and the level of fluid above the point of measurement so you need to check these things while calculating the hydrostatic pressure.

### Hydrostatic Pressure

If you wish to measure the pressure of a static fluid then you are required to obtain the weight of the fluid column above the point on which you are trying to measure the pressure. This is the major reason that the pressure of a non-flowing fluid is totally dependent on some specific things such as the gravitational acceleration, the density of the fluid, the atmospheric pressure and the height of the liquid calculated above the point on which you need to measure the pressure. In other words, you can say that the Hydrostatic Pressure is the force that is exerted by the collisions of particles. From this definition, you can estimate the pressure by using the molecular kinetic theory of gasses and gas equation. The word of the Hydrostatic is formed by two terms, “hydro” which means water and the “static” which means non-changing. From the meaning of the hydrostatic word, the pressure of the non-flowing water is called the Hydrostatic Pressure. But in the practical implementation, the Hydrostatic Pressure is applicable to any fluid and even gasses. As the term of the hydrostatic pressure means the weight of the fluid column present just above the measured point, the formula of the hydrostatic pressure is “P = hdg”. From the letter, we mean the hydrostatic pressure, h denotes the height of the surface of the fluid just above the measured point and the letter d is used for the density of the fluid while the letter g is the gravitational acceleration. In order to calculate the total pressure on the measured point, you need to add the hydrostatic pressure and the external pressure that is known as the atmospheric pressure as well on the fluid surface. The fluid should be in static form in order to generate the Hydrostatic Pressure.

### Osmotic Pressure

If you have a situation in which two solutions containing different solute concentrations are separated with the aid of a semi permeable membrane then it is a natural phenomenon that the solvent present at the low concentrated side will show the tendency of moving to the high concentration side. In this situation, the solvent will transfer to the inside of the membrane causing the pressure of the inside of the membrane to go up. From the term of the osmotic pressure, we mean this risen pressure. The mechanism of the osmotic pressure is essential in lots of cases particularly in the process of transferring water to the inside of the cells. If the osmotic pressure phenomenon not occurs, the animal’s cells and the tress will not able to survive. In some cases, the inverse of osmotic pressure is also present known as the water potential. The water potential is the trend the solvent to stay in the solution. In the situations where the osmotic pressure is high, the water potential is low and vice versa. The osmotic pressure is not the actual force but it is referring to a gradient. For the sake of having the osmotic pressure, the presence of two solutions with unequal levels of concentration is a must.

### Key Differences between Hydrostatic Pressure and Osmotic Pressure

1. You can analyze the Hydrostatic pressure in any fluid, present in the static state. In order to observe the Osmotic pressure, having a specific system is compulsory containing the solution and the solvent separated by a semi permeable membrane.
2. Not to have a pure fluid is the prerequisite of the Osmotic pressure in which two different concentrated solutions should be present. For having the Hydrostatic pressure, you need to have one fluid only.
3. There is no concept of the semi permeable membrane is the Hydrostatic pressure. Having semi permeable membrane separating the two fluids is vital for Osmotic pressure.