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Homework Help: Science: Earth: Air Pressure
by Kristyn Conner
Air pressure, the weight of tiny molecules, is the force that pushes down on all surfaces it touches. It plays an important role in weather. Although the molecules cannot be seen, they still have weight and take up space.
Air pressure is everywhere. Why, then, doesn't it push down and squash us? Well, we have air pressure inside our bodies, too. Air balances out the outside pressure so that we can stay nice and firm.
Air pressure is not just about exerting force on us. It can also tell us about what kind of weather to expect in our areas. There are two kinds of systems involving air pressure. High pressure systems are one while another involved low pressure systems. If a high pressure system is coming toward your area, frequently you can expect cooler temperatures and clear skies. If a low pressure system is on its way, then you should expect humid temperatures and stormy weather.
Air molecules are not equaled out in the atmosphere. The higher in the atmosphere you go, the fewer air molecules there will be. This means that there will be a decrease in air pressure. Have you ever been to the top of a tall mountain? If you have, you may have ralized that your ears pop. This is a result of the decrease in air molecules. Your ears pop so that they can balance out the pressure between the interior and the exterior of your ear. Since you are breathing less oxygen molecules,you may need to breathe more faster to breathe in the few air molecules that there are into your lungs to make up for the ones not gained in one breath.
Although we can be in an area with lots of pressure and realize it, we do not know the exact measurements. Air pressure is measured with a mercury barometer, which is mercury in a glass column. It is measured in millibars (mb), which is equal to 100 newtons per square mile, or inches in mercury. A measurement of 29.92 inches of mercury is just the same as 1013.25 millibars.
Gravity is important in the role of air pressure too. The molecules in the air, as we already know, is the matter that pushes down to create air pressure. What we did not know before was that gravity pulls the air downward to give the molecules their weight. The molecules can't exert force without gravity pushing down on them.
Homework Help: Science: Earth
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