Pascals to Standard Atmospheres (Pa to atm)
1 pascal equals 0.000009869232667 standard atmospheres (rounded).
How to convert pascals to standard atmospheres
To convert pascals to standard atmospheres, multiply the number of pascals by 0.000009869232667. The factor is rounded to 10 significant digits. To go the other way, multiply standard atmospheres by 101,325.
standard atmospheres = pascals × 0.000009869232667
Example: 10 pascals = 0.00009869232667 standard atmospheres.
About these units
Pascal (Pa)
The SI unit of pressure: one newton per square meter. A very small unit; atmospheric pressure is about 101,325 Pa.
Blaise Pascal never saw a pascal, because the name was adopted by the 14th CGPM in 1971 for the newton per square meter. He did, however, earn the honor. In 1647 he published experiments on the vacuum, and on 19 September 1648 his brother-in-law Florin Périer carried a mercury barometer up the Puy de Dôme near Clermont, where the column stood at about 23 inches against about 26 at the base. Pascal had reasoned that air pressure should fall with altitude, and the result confirmed it.
One pascal is a tiny pressure, so the unit is mostly met with prefixes. Standard atmospheric pressure is 101,325 Pa, a typical sea-level reading is about 1,013 hPa, and the threshold of hearing in air is taken as a reference pressure of 20 micropascals. Building airtightness tests, in contrast, are run at 50 Pa.
Pascal is also remembered for hydrostatics, where he showed that pressure depends on height difference rather than the weight of the fluid, and for the hydraulic press.
The pascal is the reference unit for pressure on this site.
Sources: Wikipedia: Pascal (unit); Wikipedia: Blaise Pascal
Standard Atmosphere (atm)
Exactly 101,325 pascals, the average pressure of the atmosphere at sea level.
A column of mercury about 76 cm tall was Torricelli's measure of the air, and the standard atmosphere began as exactly that: the pressure of 760 mm of mercury at 0 degrees Celsius under standard gravity. It was used as a reference for physical and chemical properties, and the Celsius scale set 100 degrees as the boiling point of water at that pressure.
In 1954 the 10th CGPM confirmed the standard atmosphere as exactly 1,013,250 dynes per square centimeter, which is 101,325 pascals, a definition that no longer depends on the properties of any substance.
In practice one atmosphere is about 1.01325 bar, 760 mmHg, 14.696 psi or 29.92 inHg, and roughly the pressure of 10.33 meters of water. Chemistry splits on it: until 1982 standard temperature and pressure used 1 atm, but that year IUPAC recommended a standard pressure of exactly 100 kPa instead.
1 standard atmosphere = 101,325 pascals (exactly).
Sources: Wikipedia: Standard atmosphere (unit); Wikipedia: Atmospheric pressure; Wikipedia: Evangelista Torricelli
Related conversions
- Standard atmospheres to pascals (reverse)
- Pascals to kilopascals
- Pascals to bars
- Pascals to PSI
- Pascals to hectopascals
- Pascals to megapascals
- Pascals to millibars
- Pascals to torr
- Pascals to millimeters of mercury
- Pascals to inches of mercury
- Pascals to gigapascals
- Pascals to kilopounds per square inch
- Pascals to millimeters of water
- Kilopascals to standard atmospheres
- Bars to standard atmospheres
- PSI to standard atmospheres
- Hectopascals to standard atmospheres
- Megapascals to standard atmospheres
- Millibars to standard atmospheres
- Torr to standard atmospheres
- Millimeters of mercury to standard atmospheres
- Inches of mercury to standard atmospheres
- Gigapascals to standard atmospheres
- Kilopounds per square inch to standard atmospheres
- Millimeters of water to standard atmospheres
See all pressure units.