No, pressure will not significantly change the volume of the fluid so it
will not effect hydrometer readings. In virtually all practical physics,
even involving multiple atmospheres of pressure change, fluid is considered
incompressible.

Ray

"OzWineKitz" > wrote in message
om...
> You know folks,
>
> No offence intended, but it never ceases to amaze me the ignorance of
> humanity!
>
> I am aware of the arguement about temperature, because temperature
> expands a liquid - but so does low atmospherice pressure,as does lower
> gravitational force.
>
> If you lower the atmoshperic temperature then a liquid will boil at a
> lower temperature, hence its viscosity is increased at lower
> barometric pressures. As does a liquid subject to lowered
> gravitational force. It's simple physics! If one choses to ignore the
> environment then let it be, but the scientist must consider all
> factors, mustn't they?
>
> Lets say that you are breathalized by a police officer and the legal
> limit is 0.05% alcohol volume. Now lets consider if the atmospheric
> pressure is abnormally low and the ambient temperature is relatively
> high. Shouldn't it stand to reason that your REAL blood alcohol
> reading be lower than actual at the time of reading? Should we just
> simply accept the fact that the reading of 0.05 is acurate and we are
> in the wrong if the reading is 0.051? NO! Not at all - there are other
> differential factors working at hand, even though we may not be not
> aware of them.
>
> Then the same reasoning should apply to our Hydrometer readings
> because there may be other influences working at hand that we are not
> sure of.
>
> The gravitational forces of the moon DO NOT work equivalent to the
> Hydrometer reading because gravitational force is relative to weight
> and distance. This is simple grade 8 science. So the weight of your
> Hydrometer is far less significant than the weight of the liquid being
> measured for Specific Gravity, isn't it?
>
> This means that the liquid that one is measuring is being PULLED much
> more than the Hydrometer that we are measuring with, isn't it? The
> question remains, what is the significant difference of measurement?
> The same question applies to atmospheric pressure, doesn't it? The
> real question is, as to what degree or percentage is the actual
> difference?
>
> This question is not requested for speculation, but for actual
> scientific reasoning, evidence, and calculation. Does anyone have a
> scientific answer?
>
> Cheers,
> Steve!