[arachne] Re: Best tip of the year

Arachne at FreeLists---The Arachne Fan Club!

Hi L.D.,
                I find it intriguing how the topics develop
on this list.  We started with a good method to
make a tool which developed into a discussion
on watches and then on to SCUBA diving and
pressure exerted on the diver by the weight of the
water at various depths.  By the way, remember,
salt water is heavier than fresh water.  Therefore,
salt water exerts more pressure than fresh water
at the same depth.

Eric 

On Sun, 06 Nov 2005 01:34:10 -0500 "L.D. Best" <l.d.best@xxxxxxxxxxxxxxx>
writes:
> Arachne at FreeLists---The Arachne Fan Club!
> 
> Steve,
> 
> In the real world gauge pressure *is* used; that is why we dove with 
> 
> pressure gauges.  They told us how deep we had gone based upon the 
> water 
> pressure.  But anyone who trained and was certified for SCUBA would 
> have 
> learned, and learned well, the concept/fact of cumulative TOTAL 
> pressure.  That is how sea level dive charts (decompression charts) 
> are 
> calculated; that is why the calculations for high altitude SCUBA 
> decompression charts are far different from sea level.  SCUBA is 
> very 
> real world, and not a bit laboratory -- honest!
> 
> Until you've been in 10' of water and had a 20' wave pass over you, 
> popping an eardrum and hitting you with vertigo that is truly killer 
> as 
> the 40F water hits your inner ear, you might not be able to 
> appreciate 
> that aspect of actual (cumulative) pressure.
> 
> I've never seen a watch rated in "atmospheres"; they are rated in 
> depth 
> under water.  That could well be because many people, like you, 
> would 
> forget that the ambient one atmosphere of pressure must be taken 
> into 
> consideration.
> 
> However, to answer your question:  If a watch is rated at one 
> atmosphere 
> of pressure, that means you can go under water if you'd like but the 
> 
> watch can't survive.
> 
> l.d.
> ====
> 
> Steve wrote:
> 
> 
> >   You're talking absolute pressure, which is pretty much only done 
> in 
> > laboratories.  In the real world, pressure is measured in gauge 
> pressure.
> > 
> >   Just inflate your tires to observe this fact.
> > 
> >   If a watch is rated as being water resistant to 1 atm, do you 
> suppose 
> > they're telling you not to go underwater at all?
> 
> 
> Arachne at FreeLists
> -- Arachne, The Web Browser/Suite for DOS and Linux --
> 
> 


Arachne at FreeLists
-- Arachne, The Web Browser/Suite for DOS and Linux --

Other related posts: