I want to get your opinion on something.
if there is a 5 inch inside dia pipe in front of you.
and it is 28 ft tall.
it has a cap on the bottom so that it can hold water.
it has a pressure guage on the bottom cap of the 28 ft tall pipe.
it will read apx 28 ft x .433 psi = 12.124 psi when filled with water.
you then fill the pipe with water.
and you have a cap that has a connection on it for a vacuum pump on the top of the cap.
if you then connect the cap onto the top of the pipe there will be a small area below the cap that has air inside it.
if you place a vacuum on that air at the top using a simple hand vacuum pump , what would happen to the guage pressure at the bottom of the pipe.
1) the pressure guage will remain at 12.124 psi , because of the weight of the water.
in other words no change because the pressure guage is still affected by the pressure gradient in the water in the pipe.
and there is still the same amount of water weight above the pressure guage even though it no longer has atmospheric pressure pressing down on the water.
2) the pressure reading will drop because the pressure at the top of the water has decreased below 1 atm.
3) you choose to allow mommos to intervene at this time.
