Pascals to Torr (Pa to Torr)
1 pascal equals 0.007500616827 torr (rounded).
How to convert pascals to torr
To convert pascals to torr, multiply the number of pascals by 0.007500616827. The factor is rounded to 10 significant digits. To go the other way, multiply torr by 133.3223684 (rounded).
torr = pascals × 0.007500616827
Example: 10 pascals = 0.07500616827 torr.
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
Torr (Torr)
Exactly 1/760 of a standard atmosphere (about 133.322 Pa), named after Evangelista Torricelli. Used for vacuum measurement.
In 1643 Evangelista Torricelli filled a meter-long tube, sealed at one end, with mercury and stood it in a basin of mercury. The column fell to about 76 cm and left a Torricellian vacuum above it, the first recorded creation of a permanent vacuum. In a letter dated 11 June 1644 he described living at the bottom of a sea of air, an idea that also explained why suction pumps could raise water only about 10 meters.
The torr honors him. It was originally meant to equal one millimeter of mercury at 0 degrees Celsius, but the weight of a mercury column varies with gravity, which changes with elevation and latitude. In 1954 the 10th CGPM defined the standard atmosphere as 101,325 Pa, and the torr was then fixed as exactly one 760th of that, about 133.32 Pa.
Today the torr is mostly met in high-vacuum physics and engineering. It differs from the millimeter of mercury by less than one part in seven million, so the two are interchangeable except in the most exacting work.
1 torr = 133.3223684 pascals (approximately).
Sources: Wikipedia: Torr; Wikipedia: Evangelista Torricelli; Wikipedia: Standard atmosphere (unit)
Related conversions
- Torr to pascals (reverse)
- Pascals to kilopascals
- Pascals to bars
- Pascals to standard atmospheres
- Pascals to PSI
- Pascals to hectopascals
- Pascals to megapascals
- Pascals to millibars
- 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 torr
- Bars to torr
- Standard atmospheres to torr
- PSI to torr
- Hectopascals to torr
- Megapascals to torr
- Millibars to torr
- Millimeters of mercury to torr
- Inches of mercury to torr
See all pressure units.