A pascal unit is a term used to define a unit of pressure, tensile strength, stress and elasticity (Young's modulus). The term is commonly used in meteorology to describe atmospheric pressure but has other applications to describe pressure on an object. The term is used only in countries that have adopted International System of Units.
Pressure is the exertion of force of an object on another object. Atmospheric pressure, for example, is the weight of the air on a specific area of the earth. Though the atmosphere surrounds the entire earth, different columns of air can create different levels of pressure in different locations just as a storm can occur on one side of town and not the other. A book on a table corner exerts pressure on the corner of the table only. Pressure is a key variable in paring an apple. The pressure of the knife on the apple varies in accordance with the sharpness of the knife. A sharper knife has a smaller area of contact with the apple and requires less force to peel.
History of the Term
Blaise Pascal was a noted scientist and philosopher in the 17th century. The pascal unit was named after Pascal in recognition of his contributions to the scientific understanding of hydraulic pressure. He realized that if pressure was applied to liquid in a container, the fluid would not be lost. Instead, pressure on a fluid would cause the fluid to be displaced without compression. He invented the syringe and the hydraulic press in response to his discoveries.
The pascal unit is written in long hand as "pascal unit" or in abbreviation as "Pa." One pascal is equal to 1 newton per square meter (N/m^2). A newton measures the force required to one kilogram one meter per second squared (N=kg*m/s^2). Because the pascal is often too small for scientific or industrial use, it may be represented in kilopascals (kPa), which equal 1,000 Pa, or hectopascals (hPa), which equal 100 Pa.
Pascal units may be converted into torr, bars, atmospheric pressure and pounds per square inch (psi). Since the pascal is the smaller unit of measurement, 1 pascal converts to a fraction of these units. For example, it takes more than 100,000 pascal to comprise one bar.