11+Gas+Pressure

=__Gas Pressure__ By Emily Peiffer and Justin Griffin = = = = = __** Pressure **__- the ratio of force to the area over which that force is distributed: P = þgd ( pressure = density x gravity x depth)

__Pressure in a Gas __- molecules are far apart and free from cohesive forces - gas expands, fills space, and exerts pressure against its container - pressure is proportional to density __** Boyle's Law **__- pressure x volume at one time = pressure x volume at another time: P1 x V1 = P2 x V2 - as long as temperature remains the same = = __**

Archimedes' Principle **__- an object surrounded by air is buoyed up by a force equal to the weight of the air displaced - air becomes less dense with altitude - same volume of air weighs less and less as it rises __ Bernoulli's Principle __- when the speed of a fluid increases, pressure in the fluid decreases - when fluid flows through narrow constriction, its speed increases



