Bar
The bar is a pressure unit in the metric system, equivalent to 100,000 pascals. It was created in the early 1900s to serve the needs of engineers and industry professionals, especially for measuring pressures in the atmosphere and fluids. While it is not officially a part of the SI system, the bar remains popular in fields such as meteorology, diving, and mechanical engineering because of its convenient scale. For example, normal atmospheric pressure at sea level is close to 1.013 bar. The bar provides an easy-to-use alternative to SI units for everyday applications while still maintaining compatibility with metric measurements.
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.