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What instruments are used to measure pressure?
There are a few different instruments used to measure air pressure. One common one is the barometer.
Another type of pressure gauge is the Bourdon tube. It is used to measure the pressure of gases or liquids in a sealed container. It consists of a flattened tube that is shaped like a “C.” When the pressure outside the tube is greater than the pressure inside, the “C” curls up more. When the pressure inside is greater the “C” uncurls more, just like those party favors horns that uncurl when you blow into them. The “C” shaped tube is connected to a dial that moves with the changes in pressure to display the pressure.
Aneroid barometers are a third type. They use vacuum capsules called cells. These cells have a spring in them that keeps them from collapsing. As air pressure changes, the cell expands and contracts, and a device measures this. Some planes use aneroid barometers, which indirectly allow them to measure their altitude, since pressure decreases the higher you go.
