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Menu for converting units
This metric system conversion calculator for pressure can be used for converting:
- psi to bar
- pascal to bar
- psi to pascal
- bar to psi
- psi to atmosphere
Use this conversion calculator to convert American/Britis units to the metrical (SI) units.
Definition of pressure:
Pressure (p) is a derived unit with a own name. The name is Pascal (Pa), also known as N/m2. in SI this will be kg·m-1·s-2 (kg/m·s2).
Source: http://www.nmi.nl/english/about_metrology/quantities_and_units/some_important_derived_units_with_own.htm
Source: http://physics.nist.gov/cuu/Units/current.html
History:
The unit of pressure used to be torr, also known as mmHG (millimeter mercury). Some mercury was put in a glass tube. If the pressure changes, the level of the mercury in the tube changes with it. The reason that mercury is used is that the thermal expansion of mercury is big and is mostly homogeneous. Mercury also doesn't stick to the glass. It was calibrated that on sea-level the height of the mercury was 760 mm. At sea-level the pressure is also defined as 1 atmosphere, that's why 1 atmosphere equals 760 torr. If you measure the pressure in Pascal at sea-level, you will find 101325 Pa. This also equals one atmosphere.
Relation with temperature and volume:
Pressure is related with temperature and volume. If the volume is constant and the temperature gets higher, the pressure also gets higher. This is because the molecules gets more energy and move faster. The relation is given with:
p * V = c*T :
p in Pa
V in m3
T in K
c is a constant value, we have taken one, but you can also take another value in its place.
Lenntech BV is not responsible for programming or calculation errors on this sheet. Feel free to contact us for any feedback.
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