Editing Pascal (unit) (section)

{{Short description|SI derived unit of pressure}}
{{redirect|Pascals|other uses|Pascal (disambiguation)}}
{{Redirect|Hectopascal|the song|Hectopascal (song)}}
{{Use dmy dates|date=December 2020}}
{{Infobox Unit
| bgcolour =
| name = pascal
| image = [[File:Psidial.jpg|250px]]
| caption = A [[pressure gauge]] reading in [[Pounds per square inch|psi]] (red scale) and kPa (black scale)
| standard = [[SI]]
| quantity = [[pressure]] or [[Stress (physics)|stress]]
| symbol = Pa
| namedafter = [[Blaise Pascal]]
| units1 = [[SI base unit]]s:
| inunits1 = [[Kilogram|kg]]&sdot;[[metre|m]]<sup>−1</sup>&sdot;[[second|s]]<sup>−2</sup>
| units2 = [[US customary units]]:
| inunits2 = {{cvt|1e0|Pa|psi|sigfig=6|disp=out|lk=out|comma=gaps}}
| units3 = [[Atmosphere (unit)|atmosphere]]:
| inunits3 = {{convert|1|Pa|atm|sigfig=6|disp=out|comma=gaps}}
| units4 = [[Bar (unit)|bar]]:
| inunits4 = 10<sup>−5</sup> bar
| units5 = [[barye]] (CGS unit)
| inunits5 = 10 Ba
}}

The '''pascal''' (symbol: '''Pa''') is the unit of [[pressure]] in the [[International System of Units|International System of Units (SI)]]. It is also used to quantify [[internal pressure]], [[stress (physics)|stress]], [[Young's modulus]], and [[ultimate tensile strength]]. The unit, named after [[Blaise Pascal]], is an [[SI coherent derived unit]] defined as one [[Newton (unit)|newton]] per [[square metre]] (N/m<sup>2</sup>).<ref>{{SIbrochure8th|page=118}}</ref> It is also equivalent to 10 [[barye]] (10 Ba) in the [[Centimetre–gram–second system of units|CGS]] system. Common multiple units of the pascal are the hectopascal (1&nbsp;hPa = 100&nbsp;Pa), which is equal to one [[Bar (unit)#Usage|millibar]], and the kilopascal (1&nbsp;kPa = 1000&nbsp;Pa), which is equal to one centibar.

The unit of measurement called ''[[Standard atmosphere (unit)|standard atmosphere (atm)]]'' is defined as {{val|101,325|u=Pa}}.<!-- not kPa - the comma here separates the thousands in 101325 per [[WP:DIGITS]], it's not a decimal separator --><ref name="BIPM">{{cite web|url=http://www.bipm.org/jsp/en/ViewCGPMResolution.jsp?CGPM=10&RES=4 |publisher=[[BIPM]] |title=Definition of the standard atmosphere|access-date=2015-02-16}}</ref>
[[Meteorology|Meteorological]] observations typically report [[atmospheric pressure]] in hectopascals per the recommendation of the [[World Meteorological Organization]], thus a standard atmosphere (atm) or typical sea-level air pressure is about 1013&nbsp;hPa. Reports in the United States typically use [[inches of mercury]]<ref>{{Cite web|url=https://w1.weather.gov/glossary/index.php?word=inches+of+mercury|title=National Weather Service glossary page on inches of mercury}}</ref> or millibars (hectopascals).<ref>{{Cite web|url=https://www.wpc.ncep.noaa.gov/sfc/90fwbg.gif|title=US government atmospheric pressure map}}</ref><ref>{{Cite web|url=https://s.w-x.co/util/image/map/WEB_Current_Weather_Map_1280x720.jpg?v=ap&w=1280&h=720&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0|title=The Weather Channel}}</ref> In Canada, these reports are given in kilopascals.<ref>{{Cite web|url=https://weather.gc.ca/canada_e.html|title=Canadian Weather – Environment Canada|first=Environment|last=Canada|date=16 April 2013|website=weather.gc.ca}}</ref>