Mike
    While I agree completely with you that definitions of STP can vary according
to use, I believe the original question delt with STP as related to gas laws.
In that case it would be the values defined and accepted in Physics.  This is
requireds to remove rariations in calculations resulting from molecular movement
at temps above absolut zero.  On the other hand the whole discussion is some
what accidemic as gas laws only apply in an "ideal"  universe, and as yet we
have not reached that level of nervana.
Dive Safe, Dive Fun
jimbo
Mike Rodriguez wrote:

> At 12:43 PM 2/8/99 -0700, Jimmy L. Stanford wrote:
>
> >    I don't know why a calibration manual would be so far off but STP is
> >defined as 273.15K which is freezing temp of H2O (0C or 32F).  Pressure is
> >1.013x10^5 Pa or 1 ATM.  This is the standard used in all Physics text.  I
> >double checked it to make sure Snow & Shull Physics text page 374 and index
> >(both agree on same values).  Hope this clears up some of the confusion.
>
> Standard temperature and pressure is different in different
> contexts.  There is no one true standard.  In aviation, for
> example, standard temperature is 59F and standard pressure is
> 29.92" or 1013mb.  Same for meteorology, but in physics standard
> temperature is 273.15K or 0C, in human physiology, it's 98.6F, etc.
>
> A good standard has three qualities... it's easy to write,
> it's easy to use as a baseline reference, and it's a convenient
> magnitude in the context of the discipline in which it is used;
> so, volcanologists use a different standard temperature
> than biologists.  This is as it should be.
>
> The weight you come up with for a given volume of air depends
> on the context.  To be really precise, you have to indicate
> the volume, temperature, pressure, and even humidity before
> your calculated weight makes any sense.

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