[USMA:23557] Re: atmosphere and gravity and more

[kilopascal]

2002-11-24     I often wondered myself if room temperature was 293.15 K (20 �C) or 298.15 K (25 �C).  It seems to be both.  Maybe it depends on location and season.  Maybe in the winter time it is 20 �C and the summer it is 25 �C.  Or maybe it has to do more with the tropics vs. the temperate zones.  The products I work with use 25 �C as the base or room temperature.   101.325 kPa just happens to be the actual temperature measured at sea level under prescribed conditions and is not just a conversion from 760  mm Hg.    atmosphere (atm or atmos) a unit of pressure designed to equal the average pressure of the Earth's atmosphere at sea level. In other pressure units, one atmosphere equals exactly 1013.25 millibars (mb), 101.325 kilopascals (kPa), approximately 29.92 inches of mercury (in Hg), or 14.6959 pounds of force per square inch (lb/in2). This is the standard atmosphere; it equals 1.0332 technical atmosphere.   torr (Torr) a non-metric unit of pressure equal to exactly 1/760 atmosphere, about 1.333 22 millibars, 133.322 pascals, or 0.019 337 pound per square inch (psi). The pressure of 1 atmosphere is almost exactly equivalent to the pressure of a column of 760 millimeters of mercury in a mercury barometer. As a result, 1 torr is the same thing as 1 mmHg within 1 part per million. In engineering, the pressures of near-vacuums are often stated in torr. The unit is named for Evangelista Torricelli (1608-1647), the Italian scientist who invented the barometer.   John   ----- Original Message ----- From: Matthew Zotter To: U.S. Metric Association Sent: Sunday, 2002-11-24 09:19 Subject: [USMA:23555] atmosphere and gravity and more 2002 NOV 24 SUN   What society defined standard atmospheric pressure to be 101.325 kPa (I know the value came from 760 torr) and standard gravity to be 9.80665 m/s^2?  Is standard room temperature 293.15K or 298.15 K or both?  Do any of you know were I could get a thermometer that reads in kelvins.   Thank you for you time.   Matthew Zotter