Water compressibility minutia

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Posted by Wayne on October 04, 2000 at 15:36:02:

In Reply to: Re: Let's debate more minutia posted by Eins on October 04, 2000 at 13:23:41:

Water is pretty incompressible, but it does compress -- reduces its volume at increased pressures!

And the compressibility of of "crushed neoprene" should be very low since the ratio of elasomer to gas bubble is so great. Even if the bubbles want to behave according to Boyle, the deformation characteristics of the material will have an impact on the overall reeduction in volume I believe this is the figure of merit stuff).

Not knowing for sure, I will hazard a guess about it and see "experts" prove me generally right or wrong. I assume that in the proper use of a dry suit, very little of the buoyancy (meanign the additional buoyancy of the diver wearing his/her exposure suit)comes from the shell material. I belive that most of the buoyancy comes from the volumetric displacement caused by the undergarments and trapped air. These volumes are affected by Boyle's stuff (Ok a little of the undies' volume does not really change in a linear fashion). I expect the shell material's change-in-buoyancy to be virtually undetectable when the entire suit system is analyzed using pressures likely to be encountered in non-commercial diving.

For the interested, here is the compressibility stuff on Water! Call me odd, but I think this stuff in fascinating. And it amazes me that the data is readily found.

Volume of Water as a Function of Pressure and Temperature:

temp 0 atm 500 a 1000 a 2000 a 3000 a
32 (0) 1.0000 0.9769 0.9566 0.9223 0.8954
68 (20) 1.0016 0.9804 0.9619 0.9312 0.9065
122(50) 1.0128 0.9915 0.9732 0.9428 0.9193

Pressure in in guage style atmospheres and temp is in both F and C types of degrees. Many other liquids are more compressible than water.

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