What is the relationship between depth and pressure in water?

[Dickfore]

Oh for goodness sake read post14.

Your formula gives a pressure of zero for h=0, not good news for any breathing animal.

Which is true, since the hydrostatic pressure is zero at the water surface. Also, this has nothing to do with the coefficient \Delta P/\Delta h since an addition of a constant cancels out when calculating the slope.

 

[Studiot]

Which is true, since the hydrostatic pressure is zero at the water surface.

This is just plain old fashioned wrong.

The hydrostatic pressure at the water surface equals the atmospheric pressure there. The pressure difference (as mentioned by Russ) is zero.

Of course the slope (which you calculated) is the same - this is true of any linear relationship.

 

[Dickfore]

This is just plain old fashioned wrong.

The hydrostatic pressure at the water surface equals the atmospheric pressure there.

You seem so confident. How would you go on proving this?

 

[Studiot]

If it wasn't the atmosphere would be pushing the water aside.

 

[Dickfore]

If it wasn't the atmosphere would be pushing the water aside.

So, according to you, the water acts on itself to be in equilibrium with an external force applied to it. Nice. What's next. Perpetually moving machines?

 

[Studiot]

I've tried to be subtle here and I've tried to be nice.

The free surface of any liquid on this planet is subject to the local atmospheric pressure on the gas side of the boundary. This is balanced exactly by liquid hydrostatic pressure on the liquid side of the boundary. At sea level this pressure is defined as 1 atmosphere.

 

[Dickfore]

I've tried to be subtle here and I've tried to be nice.

The free surface of any liquid on this planet is subject to the local atmospheric pressure on the gas side of the boundary. This is balanced exactly by liquid hydrostatic pressure on the liquid side of the boundary. At sea level this pressure is defined as 1 atmosphere.

No, this is not true. Pressure gets transmitted through bulk materials in all directions. The pressure at the sea level is solely due to the column of air above it, hence it is atmospheric and has no hydrostatic contribution.

 

[Studiot]

So are you are saying that the air pushes on the liquid, but the liquid does not push back equally on the air?

 

[Dickfore]

So are you are saying that the air pushes on the liquid, but the liquid does not push back equally on the air?

So, let me ask you this. According to you, the pressure at any height is caused not only by the column of air + water above you pushing down due to its own weight, but also because the column of air + water below you pushes upwards. Pray tell, how does the pressure exerted on the object depend on the depth of the column of air + water below you?