Re: [APD] To pearl or not to pearl...

[Liz Wilhite <satirica at gmail_com>]

On Thu, 17 Mar 2005 13:14:08 -0600, Douglas Guynn <d_guynn at sbcglobal.net> wrote:
> I've been through this discussion before and no one could explain to me
> where the gasses for super-saturation come from.

Lots of places.  The water coming out of the tap is at a pressure
higher than room pressure.  Outgassing can occur when the pressure
drops because the solubility of the gas also drops.  I believe that in
human beings this phenomenon is called "the bends".  The method by
which water is changed can induce a temporary state in which excess
gases are dissolved then released afterwards.  "Super-saturation" is a
non-equilibrium (i.e. temoporary) condition that may be easily created
by accident.

Fill a 10 gallon, smooth sided container with water using the same
method you use to fill your aquarium.  Drop a piece of rough wood in,
keep the temperature the same as your aquarium and look to see if the
wood gets bubbles on it.  That's outgassing.  If the wood doesn't get
bubbles on it you can be pretty certain the bubbles are pearling.

-- 
Liz
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