# Pounds force per square inch to pascal converter

Technical and physical pressure is a scalar derived physical size, defined as the ratio of the force and unit area, the force is applied in the direction perpendicular to the surface considered. It is usually represented by one of the symbols P, P (more rarely, by H or H). The relative pressure is the pressure difference from the atmospheric pressure. Molecules in the fluid at rest are in continuous Brownian motion. As the number of molecules and their movement is very random individual is not observed any movement macroscopically.

If the fluid is enclosed in a vessel, it will be seen that there is a pressure on the walls of the vessel walls due to the impact of the fluid molecules. Wherever these walls would be placed even in the vessel, the pressure will be the same everywhere. The vessel may be reduced to a spot size, the pressure will have a single value. It follows that the pressure is a scalar, not a vector, it has a value, but not associated with a direction in which it is carried. Inside the fluid pressure is exerted in all directions, and the areas surrounding the area, perpendicular to these surfaces.