Inches of Water Column

When one speaks of inches of water column, the diameter of that water column doesn’t really matter, does it? If P = pgh (where p=density) and P = F/A, then because pressure is per unit area…the diameter of that water coumn doesn’t matter, right?

So, whether a 5-ft column of water in a pipe or 5-ft column of water in a 55-gal drum, the water pressure at the bottom is the same, correct? (Note: 1 psi = 2.31 ft x 12 in/ft = 27.72 in)

  • Jinx

The short answer is no, the diameter doesn’t matter.

The long answer is that some people will nitpick over things like surface tension, wetting, the meniscus, quantum effects, and such.

I saw a mill pond in Connecticut a few years back where the damn had been modified to make the reservoir a bit deeper. On a 50 foot wide dam, they ran a string of 2X10’s flat across the top, bolted them on, and nailed some more 2X10"s perpendicular to the first set. It worked. The pond was hundreds of feet long.

Basically, yes. And when you go Scuba diving, the pressure you encounter at a certain depth does not depend on the size of the lake.

If the diameter of the tank made a difference then something like this ought to work.

Jinx, your profile lists your occupation as Engineering. Care to clarify what sort of engineering?