I know that the average PSI at sea level is 14.7 PSI, I just don’t understand why gauges and other PSI measuring equipment dont account for outside atmospheric conditions.
For example, if you were filling a scuba tank at sea level, the gauge would say 0 PSI instead of 14.7. And when you do fill the tank up by 100 PSI (I don’t know how much a scuba tank holds), it would say 100, not 114.7.
It’s the same with vacuum chamber gauges. Instead of going from 14.7-0, they go from 0 to around -30 PSI. Where is the extra 15.3 PSI coming from? I assume that it is just standard to start at 0 PSI for all gauges, but it’s a bit confusing. Because if you were were on top of a mountain then the gauge wouldn’t be accurate.
In: Physics
Why would the gauge read 14.7 instead of 0, or 114.7 instead of 100? The gauge is telling you the pressure inside the rigid tank. The extra 14.7 you’re referencing is outside the tank.
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