pascal  

General information  
Unit system  SI 
Unit of  pressure or stress 
Symbol  Pa 
Named after  Blaise Pascal 
Conversions  
1 Pa in ...  ... is equal to ... 
SI base units:  kg⋅m^{−1}⋅s^{−2} 
US customary units:  1.45038×10^{−4} psi 
atmosphere:  9.86923×10^{−6} atm 
bar:  10^{−5} bar 
barye (CGS unit)  10 Ba 
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is a SI coherent derived unit defined as one newton per square metre (N/m^{2}).^{[1]} It is also equivalent to 10 barye (10 Ba) in the CGS system. Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa), which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa), which is equal to one centibar.
The unit of measurement called standard atmosphere (atm) is defined as 101,325 Pa.^{[2]} Meteorological observations typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization, thus a standard atmosphere (atm) or typical sealevel air pressure is about 1013 hPa. Reports in the United States typically use inches of mercury^{[3]} or millibars (hectopascals).^{[4]}^{[5]} In Canada these reports are given in kilopascals.^{[6]}
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Unit conversion of Pascal  Pascal to N/m2  How to convert kpa to N/m2How to convert Mpa to N/mm2

pascal to N/cm2

Unit Conversion  How to Convert Pascal to atmospheric pressure (Pa to atm)

Pascal (unit)

Pressure Unit Conversion  How can convert kg/cm2 to psi?  bar to psi  kg/cm2 to bar 
Transcription
Etymology
The unit is named after Blaise Pascal, noted for his contributions to hydrodynamics and hydrostatics, and experiments with a barometer. The name pascal was adopted for the SI unit newton per square metre (N/m^{2}) by the 14th General Conference on Weights and Measures in 1971.^{[7]}^{[8]}
Definition
The pascal can be expressed using SI derived units, or alternatively solely SI base units, as:
where N is the newton, m is the metre, kg is the kilogram, s is the second, and J is the joule.^{[9]}
One pascal is the pressure exerted by a force of magnitude one newton perpendicularly upon an area of one square metre.
Standard units
The unit of measurement called an atmosphere or a standard atmosphere (atm) is 101325 Pa (101.325 kPa).^{[10]} This value is often used as a reference pressure and specified as such in some national and international standards, such as the International Organization for Standardization's ISO 2787 (pneumatic tools and compressors), ISO 2533 (aerospace) and ISO 5024 (petroleum). In contrast, International Union of Pure and Applied Chemistry (IUPAC) recommends the use of 100 kPa as a standard pressure when reporting the properties of substances.^{[11]}
Unicode has dedicated codepoints U+33A9 ㎩ SQUARE PA and U+33AA ㎪ SQUARE KPA in the CJK Compatibility block, but these exist only for backwardcompatibility with some older ideographic charactersets and are therefore deprecated.^{[12]}^{[13]}
Uses
The pascal (Pa) or kilopascal (kPa) as a unit of pressure measurement is widely used throughout the world and has largely replaced the pounds per square inch (psi) unit, except in some countries that still use the imperial measurement system or the US customary system, including the United States.
Geophysicists use the gigapascal (GPa) in measuring or calculating tectonic stresses and pressures within the Earth.
Medical elastography measures tissue stiffness noninvasively with ultrasound or magnetic resonance imaging, and often displays the Young's modulus or shear modulus of tissue in kilopascals.
In materials science and engineering, the pascal measures the stiffness, tensile strength and compressive strength of materials. In engineering the megapascal (MPa) is the preferred unit for these uses, because the pascal represents a very small quantity.
Material  Young's modulus (GPa) 

Nylon 6  2–4 
Hemp fibre  35 
Aluminium  69 
Tooth enamel  83 
Copper  117 
Structural steel  200 
Diamond  1220 
The pascal is also equivalent to the SI unit of energy density, the joule per cubic metre. This applies not only to the thermodynamics of pressurised gases, but also to the energy density of electric, magnetic, and gravitational fields.
The pascal is used to measure sound pressure. Loudness is the subjective experience of sound pressure and is measured as a sound pressure level (SPL) on a logarithmic scale of the sound pressure relative to some reference pressure. For sound in air, a pressure of 20 μPa is considered to be at the threshold of hearing for humans and is a common reference pressure, so that its SPL is zero.
The airtightness of buildings is measured at 50 Pa.^{[15]}
In medicine, blood pressure is measured in millimeters of mercury (mmHg, very close to one Torr). The normal adult blood pressure is less than 120 mmHg systolic BP (SBP) and less than 80 mmHg diastolic BP (DBP).^{[16]} Convert mmHg to SI units as follows: 1 mmHg = 0.13332 kPa. Hence normal blood pressure in SI units is less than 16.0 kPa SBP and less than 10.7 kPa DBP. These values are similar to the pressure of water column of average human height; so pressure has to be measured on arm roughly at the level of the heart.
Hectopascal and millibar units
The units of atmospheric pressure commonly used in meteorology were formerly the bar, (100,000 Pa) which was close to the average air pressure on Earth, and the millibar. Since the introduction of SI units, meteorologists generally measure pressures in hectopascals (hPa) unit, equal to 100 pascals or 1 millibar.^{[17]}^{[18]}^{[19]}^{[20]}^{[21]}^{[22]}^{[23]} Exceptions include Canada, which uses kilopascals (kPa). In many other fields of science, prefixes that are a power of 1000 are preferred, which excludes the hectopascal from use.^{[24]}^{[25]}
Many countries also use millibars. In practically all other fields, the kilopascal (1000 pascals) is used instead.^{[26]}
Multiples and submultiples
Decimal multiples and submultiples are formed using standard SI units.
Multiples  Submultiples  

Value  Name  Symbol  Value  Name  Symbol 
10^{1} Pa  decapascal  daPa  10^{−1} Pa  decipascal  dPa 
10^{2} Pa  hectopascal  hPa  10^{−2} Pa  centipascal  cPa 
10^{3} Pa  kilopascal  kPa  10^{−3} Pa  millipascal  mPa 
10^{5} Pa  bar (nonSI unit)  bar  10^{−6} Pa  micropascal  μPa 
10^{6} Pa  megapascal  MPa  10^{−9} Pa  nanopascal  nPa 
10^{9} Pa  gigapascal  GPa  10^{−12} Pa  picopascal  pPa 
10^{12} Pa  terapascal  TPa  10^{−15} Pa  femtopascal  fPa 
10^{15} Pa  petapascal  PPa  10^{−18} Pa  attopascal  aPa 
10^{18} Pa  exapascal  EPa  10^{−21} Pa  zeptopascal  zPa 
10^{21} Pa  zettapascal  ZPa  10^{−24} Pa  yoctopascal  yPa 
10^{24} Pa  yottapascal  YPa  10^{−27}Pa  rontopascal  rPa 
10^{27} Pa  ronnapascal  RPa  10^{−30} Pa  quectopascal  qPa 
10^{30} Pa  quettapascal  QPa 
See also
 Atmospheric pressure which gives the usage of the hbar and the mbar
 Centimetre of water
 Meteorology
 Metric prefix
 Orders of magnitude (pressure)
 Pascal's law
 Pressure measurement
References
 ^ International Bureau of Weights and Measures (2006), The International System of Units (SI) (PDF) (8th ed.), p. 118, ISBN 9282222136, archived (PDF) from the original on 4 June 2021, retrieved 16 December 2021
 ^ "Definition of the standard atmosphere". BIPM. Retrieved 16 February 2015.
 ^ "National Weather Service glossary page on inches of mercury".
 ^ "US government atmospheric pressure map".
 ^ "The Weather Channel".
 ^ Canada, Environment (16 April 2013). "Canadian Weather  Environment Canada". weather.gc.ca.
 ^ bipm.fr. Archived 30 June 2007 at the Wayback Machine.
 ^ Minutes of the 14. General Conference on Weights and Measures, 1971, p. 78.
 ^ Table 3 (Section 2.2.2). Archived 18 June 2007 at the Wayback Machine. SI Brochure. International Bureau of Weights and Measures.
 ^ "Resolution 4 of the 10th meeting of the CGPM". Conférence Générale des Poids et Mesures. 1954. Archived from the original on 30 March 2021. Retrieved 5 April 2010.
 ^ IUPAC.org, Gold Book, Standard Pressure
 ^ "CJK Compatibility" (PDF). 2015. Retrieved 21 February 2016.
 ^ The Unicode Standard, Version 8.0.0. Mountain View, CA: The Unicode Consortium. 2015. ISBN 9781936213108. Retrieved 21 February 2016.
 ^ "Tensile Modulus – Modulus of Elasticity or Young's Modulus – for some common Materials". Retrieved 16 February 2015.
 ^ "Chapter 7 ResNet Standards: ResNet National Standard for Home Energy Audits" (PDF). ResNet. 2010. Archived from the original (PDF) on 26 July 2011. Retrieved 3 March 2011.
 ^ "BP Guideline  Target:BP". American Heart Association. Retrieved 18 May 2020.
 ^ "KNMI – Weer – Waarnemingen". Retrieved 4 December 2016.
 ^ "Comment convertir la pression? – IRM". Retrieved 4 December 2016.
 ^ "DWD". Archived from the original on 10 February 2008. Retrieved 20 December 2006.
 ^ "Japan Meteorological Agency – Weather Maps". Retrieved 4 December 2016.
 ^ "MDD". Archived from the original on 6 May 2006.
 ^ NOAA
 ^ United Kingdom, Met Office. "Key to symbols and terms". Retrieved 4 December 2016.
 ^ "CTV News, weather; current conditions in Montreal". Archived from the original on 4 June 2011.
 ^ Canada, Environment. "Montréal, QC – 7 Day Forecast – Environment Canada". Archived from the original on 30 November 2017. Retrieved 4 December 2016.
 ^ Ambler Thompson (Editor) Guide for the Use of the International System of Units (SI) (rev. ): The ..., p. 66, at Google Books