1atm
1 atm, or one atmosphere, is a unit of pressure commonly used in physics, chemistry, and engineering. It is defined exactly as 101,325 pascals (Pa). Historically, the unit was based on the pressure required to support a 760 millimeter column of mercury at 0 degrees Celsius in a barometer, linking it to the torr and to sea-level atmospheric pressure.
Conversions and equivalences are widely cited: 1 atm equals 101.325 kilopascals (kPa); about 14.696 pounds per
Applications and usage: 1 atm is used to describe gas pressures, calibrate instruments, and compare laboratory
Notes: Actual atmospheric pressure at sea level varies with weather and altitude, so 1 atm represents a