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Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa), which is equivalent to 1,013.25 millibars, 760 mm Hg, 29.9212 inches Hg, or 14.696 psi.
Atmospheric pressure is the force per unit area exerted by a body of air above a specified area (called an atmospheric column). It is expressed in several different systems of units, including millimeters (or inches) of mercury, pounds per square inch (psi), millibars (mb), or standard atmospheres.
- The Editors of Encyclopaedia Britannica
Oct 19, 2023 · The air around you has weight, and it presses against everything it touches. That pressure is called atmospheric pressure, or air pressure. It is the force exerted on a surface by the air above it as gravity pulls it to Earth. Atmospheric pressure is commonly measured with a barometer.
Aug 29, 2013 · The pressure that is exerted by the weight of the water down near the bottom of the bucket is greater than up near the top, so the water is “squeezed out” of the hole at the bottom. Similarly,...
Above every square inch on the surface of the Earth is 14.7 pounds of air. That means air exerts 14.7 pounds per square inch (psi) of pressure at Earth’s surface. High in the atmosphere, air pressure decreases. With fewer air molecules above, there is less pressure from the weight of the air above.
Feb 4, 2020 · By definition, atmospheric or air pressure is the force per unit of area exerted on the Earth’s surface by the weight of the air above the surface. The force exerted by an air mass is created by the molecules that make it up and their size, motion, and number present in the air.
Alison Nugent. Learning Objectives. By the end of this chapter, you should be able to: Convert between temperature units of Fahrenheit, Celsius, and Kelvin. Use mathematical formulas to define atmospheric temperature, pressure, and density. Compute pressure and density changes with altitude. Describe the vertical structure of Earth’s atmosphere.
