Bar

Definition

The bar is a metric unit of pressure, defined as exactly 100,000 pascals (Pa). It is not an SI unit but is accepted for use with the SI.

History

The bar was first introduced in 1900 by the Italian scientist Giovanni Battista Venturi. It gained popularity in the mid-20th century, especially in meteorology and engineering. The unit was defined in terms of the pascal in 1971, solidifying its relationship with the SI system.

Uses

The bar is commonly used in meteorology, engineering, and various scientific applications to measure atmospheric pressure. It's also used in tire pressure and hydraulic systems. Although primarily used in Europe, it is recognized internationally.

Conversions

• 1 bar = 0.986923 atm (atmospheres)
• 1 bar = 14.5038 psi (pounds per square inch)
• 1 bar = 0.1 MPa (megapascals)

Fun Facts

• A common misconception is that the bar is an SI unit; it is not, despite being widely used.
• The barometer, an instrument for measuring atmospheric pressure, is named after the bar unit.