mercury is the densest liquid at room temperature<\/a>. A dense liquid is helpful for pressure column applications because it minimizes the height needed for a column, which is an important practical concern. A pressure column, also called a manometer, is often used inside a laboratory. Other applications include gas pressure readings, meteorology applications, and aviation so there is a practical limit on the height of any instrument.<\/p>\nFor example, to measure one\u00a0standard atmosphere\u00a0of pressure (atm), you only need a column that is 760 mm tall (0.76 meters) if you use mercury as the liquid. On the other hand, if you use a less dense liquid, the required height of the column is greater. In the case of water, you would need a column that is 10 meters high to measure one\u00a0standard atmosphere!<\/p>\n
Other commonly used units of pressure and their abbreviations include pounds per square inch (psi), kilopascals (kPa), inches of water (inH2O), torr (Torr), technical atmosphere (kilograms-force per square cm kgf\/cm2), barad (Ba), and bar (bar).<\/p>\n