Figure 6: Pressures in the map is reported in mbar. Some scientists use the hectopascal hPa, the bar equivalent in SI, as a standard unit. The atmospheric pressures are reported mostly reported in mbar. Since then, the bar, precisely the minibar, remains a widely used unit in meteorology.

He was a well-known meteorologist and contributed to modern weather forecasting. The bar was introduced by Norwegian scientist Vilhelm Friman Koren Bjerknes. The most common derived units of the bar are the millibar (mbar), the centibar (cbar), the decibar (dbar) and the kilobar (kbar). The bar is slightly less than an atomophere (1В barВ в‰€В 0.986вЂЇ923В atm). Figure 5: Pressure Gauge Scaled in the bar It is a metric non-SI unit and defined exactly to 1В Г—В 10 5В Pa. The bar is another common unit used to measure pressure. Note: one hectopascal is equivalent to one minibar. The hectopascal (hPa) is used by meteorologists to measure the pressure of air. The gigapascal (GPa) is preferred by geophysicists since the stresses and pressures within the Earth are in a large order of magnitude. The mechanical quantities like YoungвЂ™s modulus, shear modulus, tensile strength, stiffness are displayed in the kilopascal (kPa) and the megapascal (MPa). The kilopascal is a widely used unit often atmospheric pressures are reported in kPa. The pascal is a very small unit, the micropascal is the smallest among them. The common derivatives of the pascal are the micropascal, the hectopascal, the kilopascal, the megapascal, and the gigapascal.

The International Union of Pure and Applied Chemistry recommends 1В Г—В 10 5В Pa as a reference standard pressure. The pascal can also be expressed in terms of the joule, which is the SI unit of energy. The pascal is the recognised SI derived unit of pressure and can also be expressed in terms of SI base units. Figure 4: One pascal is a force of one newton applied perpendicular to a surface of one square metre. One pascal is a force of one-newton perpendicular to a surface of one square metre. The unit pascal is christened after French mathematician Blaise Pascal. The SI unit of pressure is the pascal (Pa) or the newton per square metre (NВ m в€’2) or (kgВ m в€’1В s в€’2). Similarly for Pa to Torr, Conversion Scales mmHg to atm Figure 1: mmHg and atm Conversion Scale psi to bar Figure 2: psi and bar Conversion Scale psi to kPa Figure 3: psi and kPa Conversion Scale Pascal In the above equation, 1В Torr is the unit from the first column has a unit value, and the right-hand side of the equation, 133.322В Pa, is formed from the first-row unit and the conversion factor. A unit in the first column has a unit value (e.g., 1В Pa, 1В bar) while a unit in the first row have a value of its conversion factor. The first row and the first column represent the units and the remaining cells are the values. The above table is divided into units and values the values are conversion factors. Note: The above values are accurate up to six significant digits, and the values marked by вЂ are exact values. Table 3: Pressure Units Conversion Table Units The conversion table below gives the relationship between some important units of pressure. Pound per square inch or pound-force per square inchДЄn imperial unit of pressure, derived from psi Table 2: List of Nonstandard Units of Pressure Symbol

The other nonstandard units of pressure are listed below. It is a non-SI unit and a unit value of it is equivalent to 1 kilogram-force per square centimetreДЄ non-SI metric unit, derived from the bar The table below list important units of pressure with its symbols.

Psi pressure