What Is Air Pressure, And What Links it To the History of the Barometer?
Air pressure is the effect of the weight of air surrounding the earth, expressed as so much weight per unit of area – 14.7 pounds per square inch for example. It is a measure of the weight of a column of air on the earth’s surface, or on us for that matter. And that’s pretty important, because that great mass of air contains the oxygen we breathe, that keeps us alive. It’s a pretty subtle sort of thing too. If we have 14.7 lbs pressing down on every square inch of us, why don’t we feel weighed down? Three reasons – first it’s equally distributed all over us, it’s much less than the force of gravity, which we do feel, and we also don’t feel crushed because the pressure inside our lungs is the same as the air outside, which we breathed in. Not so obvious, and that’s probably why it took so long to discover. So let’s consider what led to the discovery of air pressure, before checking out some air pressure facts and figures. Air Pressure and the Early History of the Barometer The developme
