What is Atmospheric pressure?
[[File:Plastic bottle at 14000 feet, 9000 feet and 1000 feet, sealed at 14000 feet.png|thumb|upright|This plastic bottle was sealed at approximately 14,000 feet altitude, and was crushed by the increase in atmospheric pressure (at 9,000 feet and 1,000 feet) as it was brought down towards sea level.]] '''Atmospheric pressure''' is a force in an area pushing against a [[surface]] by the weight of the [[atmosphere of Earth]], a layer of [[air]]. The air is not distributed evenly around the globe. It moves, and at different times, the layer of air is thicker in some places than in others. Where the layer of air is thicker, there is more air. Since there is more air, there is a higher [[pressure]] in that spot. Where the layer of air is thinner, there is a lower atmospheric pressure. At higher [[altitude]], the atmospheric density and pressure are lower. This is because high places do not have as much air above them, pushing down. [[Barometer]]s can be used to measure atmospheric pressure for [[meteorology]].<ref>{{Cite encyclopedia |url= http://www.britannica.com/EBchecked/topic/41486/atmospheric-pressure |title=atmospheric pressure -- Britannica Online Encyclopedia |encyclopedia=britannica.com |access-date=11 August 2010}}</ref> There is the same atmospheric pressure from all directions. The [[International System of Units|SI]] unit for pressure is [[hPa]]. Other units such as [[Bar (unit)|bar]] and [[torr]] are used for various applications. == References == {{reflist}} == Other websites == * {{Cite web |url= http://www.teachertube.com/viewVideo.php?video_id=62613 |title=Experiment of soda cans being crushed using atmospheric pressure |work=teachertube.com |access-date=11 August 2010}} * [http://en.citizendium.org/wiki/Atmospheric_pressure Atmospheric pressure] Citizendium {{science-stub}} [[Category:Meteorology]] [[Category:Atmosphere]]