What exactly does barometric pressure measure?
When the weatherman mentions barometric pressure, he is talking about the weight of the air. Perhaps you thought of the air as a filmy nothing with no weight at all. But air does have weight. And the shifting weight of the airy atmosphere helps the weatherman to make his forecasts. The Greek word “boros” means “weight” and the old word was borrowed to name the barom eter. This gadget is really a special weight meter, or weight measurer. Its job is to weigh a small section of the airy atmosphere that begins at ground level and reaches to hundreds of miles above our heads. Anything with weight presses down upon the things below it. The weight of the atmosphere presses down with millions of tons upon the surface of the globe. The barometer measures the barometric pressure or weight of a small, tall sample of the atmosphere above it. If a solid brick weighs one pound today, we expect the same brick to weigh one pound tomorrow. Most substances do not get heavier or lighter from day to day.
