Everything about Pascal Unit totally explained
The
pascal (symbol:
Pa) is the
SI derived unit of
pressure or
stress (also:
Young's modulus and
tensile strength). It is a measure of perpendicular
force per unit
area for example equivalent to one
newton per
square meter or one
joule per cubic meter. In everyday life, the pascal is perhaps best known from meteorological air-pressure reports, where it occurs in the form of kilopascal
(1 kPa = 1000 Pa). In other contexts, the kilopascal is more commonly used, for example on bicycle tire labels. One hectopascal corresponds to about 0.1% and one kilopascal to about 1% of
atmospheric pressure (near sea level): one hectopascal is thus equivalent to a
millibar. One Newton is just under a quarter-pound of force; 1 N = 0.22481 lb
f.
Definition
» 1 pascal (Pa) ≡ 1 N·m−2 ≡ 1 J·m−3 ≡ 1 kg·m−1·s−2Origin
The unit is named after
Blaise Pascal, the eminent
French mathematician,
physicist, and
philosopher noted for his experiments with a
barometer, an instrument to measure air pressure.
The name
pascal was adopted for the SI unit
newton per
square metre by the 14th
CGPM in 1971.
(External Link
) Miscellaneous
Standard atmospheric pressure is 101,325 Pa = 101.325 kPa = 1013.25 hPa = 1013.25
mbar = 760
Torr. This definition is used for pneumatic fluid power (ISO R554), and in the aerospace (ISO 2533) and petroleum (ISO 5024) industries.
In 1985,
IUPAC recommended that standard atmospheric pressure should be harmonized to 100,000 Pa = 1
bar = 750
Torr. The same definition is used in the compressor and the pneumatic tool industries (ISO 2787).
The
Unicode computer character set has dedicated symbols ㎩ for Pa and ㎪ for kPa, but these exist merely for backward-compatibility with some older ideographic character-sets and are therefore
deprecated.
Uses
Meteorologists worldwide have for a long time measured atmospheric pressure in millibars. After the introduction of SI units, many preferred to preserve the customary pressure figures. Therefore, meteorologists use hectopascals (hPa) today for air pressure, which are equivalent to millibars, while similar pressures are given in kilopascals in practically all other fields, where the hecto prefix is hardly ever used. Since official
metrication, meteorologists in Canada use kilopascals (kPa), see for example
CTV News, weather; current conditions in Montréal
and
CBC weather, current conditions in Montréal
, although in some other countries hectopascals are still in use, see for example
KNMI
,
KMI
,
DWD
,
JMA
,
MDD
and
NOAA
.
» 1 hectopascal (hPa) ≡ 100 Pa ≡ 1 mbar.
1 kilopascal (kPa) ≡ 1000 Pa ≡ 10 hPa.
In the former
mts system, the unit of pressure is the
pièze (symbol
pz), which is equal to one kilopascal.
In the former
cgs system, the unit of pressure is the
barye (symbol
ba), which is equal to one decipascal.
Vehicle owners' guides now specify
tire inflation in kilopascals.
Airtightness testing of buildings is measured at 50 Pa or 0.2 inches of water.
Further Information
Get more info on 'Pascal Unit'.
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