Torr (mmHg)
The torr, symbolized as Torr, is a pressure unit equal to 1/760 of a standard atmosphere, approximately 133.322 pascals. Named for Evangelista Torricelli, inventor of the mercury barometer, the torr was historically central in vacuum measurement and laboratory work. This unit offers a practical scale for low pressures, particularly in physics and chemistry. While mostly replaced by SI units, such as the pascal, the torr remains essential in high-precision scientific instruments and measurements worldwide.
Pascal (Pa)
The pascal (Pa) is the official SI unit for pressure, defined as the force of one newton applied over an area of one square meter. This unit was named in honor of Blaise Pascal, a renowned French mathematician and physicist, and formally adopted in 1971 to harmonize pressure measurement standards around the world. The pascal is widely used in scientific, industrial, and engineering fields, particularly in disciplines like fluid dynamics and atmospheric science. Because a single pascal is a small unit of pressure, larger multiples such as the kilopascal are commonly employed for practical purposes. The introduction of the pascal helped achieve uniformity and accuracy in reporting pressure across different sectors globally.