Fluid Pressure. Pascal’s principle

Would you like to learn more about the physical concept of fluid pressure?

The online fluid pressure simulations on this page allow you to study in a practical way this important quality of fluids and how, thanks to Pascal’s principle, fluid pressure is translated into extremely useful practical applications.

Fluid pressure is a fundamental physical property that refers to the force exerted by a fluid on a surface due to the collisions of fluid particles. This pressure can be measured and calculated using principles of physics.

Pressure is defined as the force applied over a unit area. It is expressed in units of pressure, such as pascals (Pa), atmospheres (atm), bars (bar) or millimeters of mercury (mmHg). Pressure can be represented mathematically by the equation:

P = F/A


P is the pressure

F is the force

A is the area over which the force is applied.

Pressure in a fluid depends on several factors, such as the density of the fluid, gravity and the depth at which the fluid is located. Hydrostatic pressure, for example, refers to the pressure exerted by a fluid at rest due to its weight and is determined by the density of the fluid and the height of the fluid level. The equation for hydrostatic pressure is:

P = ρgh


ρ is the density of the fluid

g is the acceleration due to gravity

h is the height of the fluid

In addition to hydrostatic pressure, there are other types of pressures related to fluids, such as vapor pressure, atmospheric pressure and dynamic pressure. Vapor pressure refers to the pressure exerted by gaseous particles that have evaporated from a liquid. Atmospheric pressure is the pressure exerted by the earth’s atmosphere due to the weight of the column of air above a surface. Dynamic pressure is related to the motion of fluids and is used, for example, in the study of aerodynamics.

The study of fluid pressure has applications in various areas. In engineering and construction, fluid pressure is considered in the design of hydraulic structures, piping systems and tanks. In medicine, blood pressure is used as an indicator of cardiovascular health. In addition, the study of fluid pressure is fundamental in meteorology for understanding weather phenomena and in industry for the design of fluid systems, such as cooling systems and rocket propulsion systems.

Fluid pressure and flow

Explore pressure in the atmosphere and underwater. Change the shape of a pipe to see how fluid flow velocity changes. Experiment with a squirting water tower to see how height and water level determine the path of water.


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Fluids in a U-tube

Pascal’s Principle

Application of Pascal’s principle

This simulation allows us to examine a practical application of Pascal’s principle. Notice how by changing the areas on either side, it is possible to generate a large force by applying little force.
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