ERTH 20 Lecture Notes - Lecture 21: Cool Air, Density Of Air, Ideal Gas Law
13 Oct 2020
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Gas molecules are not strongly bound to one another they are in continuous motion, colliding frequently with one another and with any surfaces to which they are exposed. The atmosphere is made up of gases that have mass, and so the atmosphere has weight because this mass is pulled toward earth by gravity. Atmospheric pressure: the force exerted by the weight of these gas molecules on a unit of area of earth"s surface or on any other body. At sea level, the pressure exerted by the atmosphere is about 14. 7 pounds per. Value decreases with increasing altitude because the farther away you get from square inch, or in s. i. units, about 10 newtons (n) per square centimeter. Earth and its gravitational pull, the fewer gas molecules are present in the atmosphere. The atmosphere exerts pressure on every surface it touches. The pressure is exerted equally in all directions; outward pressure and inward pressure balance exactly.
