Cloudy hot water.
John S
It then starts the clear from the bottom up. After about a minute it is
completely clear.
What is going on?
Thanks in anticipation of an answer.
PS. We have a storage type hot water unit.
Steve Turner
What you're seeing is minute air bubbles, which have come out of
solution following the pressure drop resulting from drawing the glass
of water. As these bubbles slowly float to the surface, the liquid
clears ... from the bottom up.
Steve Turner
Real address contains worldnet instead of spamnet
John S
has a role to play too.
Is there comparatively less air in solution in cold water?
"Steve Turner" <srtu...@spamnet.att.net> wrote in message
news:fc9qlv8k0dn7jbn5n...@4ax.com...
Larry Smith
"John S" <JScheer...@msn.com> wrote in message
news:3f5d...@duster.adelaide.on.net...
> Thanks Steve. That seems to make sense. I seem to remember that
temperature
> has a role to play too.
>
> Is there comparatively less air in solution in cold water?
>
Air is relatively more soluble in cold water than in hot. It is also more
soluble
under elevated pressure.
When you withdraw the water from the heating system, etc., you drop the
pressure desolubilizing some of the dissolved gas, and causing the
cloudiness
which you have noticed. Sometimes chemical composition of the water
can also change under heat and pressure release, yielding the same sort of
effect. (For example, conversion of bicarbonate to carbonate with release
of carbon dioxide).
Steve Turner
>Thanks Steve. That seems to make sense. I seem to remember that temperature
>has a role to play too.
>
>Is there comparatively less air in solution in cold water?
Both temperature and pressure have a role.
Solubility of gases in water is typically greater at lower temperature
and at higher pressure.
Whether you see the effect you described depends mainly on the state
of aeration of the feed water. If the water coming into your house
has little or no dissolved gases, then you won't see the effect
regardless of conditions. For example, well water is usually pretty
much devoid of dissolved gas.
John S
"Larry Smith" <larr...@tellcon.net> wrote in message
news:3f5c6...@newsfeed.slurp.net...
John S
"Larry Smith" <larr...@tellcon.net> wrote in message
news:3f5c6...@newsfeed.slurp.net...
>
Dr Ivan D. Reid
wrote in <fc9qlv8k0dn7jbn5n...@4ax.com>:
> "John S" <JScheer...@msn.com> wrote:
>>If I fill a glass with hot water from my tap it appears cloudy.
>>It then starts the clear from the bottom up. After about a minute it is
>>completely clear.
>>What is going on?
> What you're seeing is minute air bubbles, which have come out of
> solution following the pressure drop resulting from drawing the glass
> of water. As these bubbles slowly float to the surface, the liquid
> clears ... from the bottom up.
If you are really lucky, and have the right sort of glass, tapping
on the glass with a spoon in the right place (so many ifs!) you might be able
to discern that the resonant frequency of the liquid column changes as the
gas bubles rise, coalesce, and disappear.
http://www.kilty.com/coffee.htm especially Ref 2 (Crawford).
--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. Ivan...@brunel.ac.uk Room 40-1-B12, CERN
KotPT -- "for stupidity above and beyond the call of duty".