Air Pressure

Can you feel air pressure? When you take off or land in an aircraft, your ears may hurt or feel uncomfortable. This is because your eardrums can feel changes in air pressure as the aircraft moves quickly up and down. But what is air pressure?

What is Air Pressure? We don’t think about it, but we are actually living at the bottom of a large pool of air. This large pool of air is called the atmosphere. It is made up of mostly colorless, odorless gases. These include nitrogen, oxygen, and carbon dioxide. The weight of all this air weighing down on us is what’s known as air pressure. The more air that is above us, the higher the air pressure will be. 

At sea level, the average air pressure is about 15 pounds for every square inch of surface area. At greater heights, the air pressure is lower, because there’s less air above weighing down.

What is Air Pressure? It is also known as atmospheric pressure. Air pressure changes with the height and also when air warms up or cools down. Changes in air pressure cause changes in the weather.

Air Pressure. . . . is not the same everywhere on earth.

3 Things that affect Air Pressure are Altitude Humidity Temperature

Altitude Air pressures decreases whenever, or increases. Temperature Humidity Altitude

Temperature Affects Air Pressure Warmer air brings lower air pressure.

Altitude Affects Air Pressure As the altitude increases the pressure decreases. The people at the bottom of the pyramid can feel all the weight and pressure of the people on top (high pressure). The person on the top doesn’t feel any weight (less pressure)

Humidity Affects Air Pressure In addition to gases, the air also contains moisture. As the humidity or moisture in the air increases the air pressure decreases

In Low Air Pressure, the air molecules are moving and are apart. fast far

In High Air Pressure, the air molecules are moving and are . slow close together

Warm air rises resulting in lower pressure Warm air rises resulting in lower pressure. On the other hand, cold air will sink making the air pressure higher. High Pressure = NICE Weather Low Pressure = STORMY

Measuring Air Pressure Air Pressure is measured in millibars (mb) on a barometer. The simplest kind of barometer is a mercury barometer and pressure is measured in mm (in) of mercury. An aneriod barometer can measure move conveniently. A barograph is a special kind of barometer, which records continuous changes in air pressure.

An aneroid barometer A barograph