[TheForge] Harden & temper

[Jerry Frost]

No, that's something else entirely Ron, though I can't think of the proper 
term right now (nucleation came to mind when I wrote it at the bottom of the 
paragraph). (Stupid TREE!) What's happening is the coffee is superheated in 
the microwave, (above boiling temp) but not boiling because the coffee cup 
is too smooth. The phase shift to boiling happens more easily if there're 
imperfections for bubbles to form on, then more bubbles form on the earlier 
bubbles. Clouds form in the same way humidity being above the dew point but 
dut no clouds form because condensation forms more easily on dust particles. 
(Nucleation! I just remembered, woo hoo! (Screw YOU stupid TREE)

Cloud seeding occurs when planes fly a pattern in/above/upwind, etc. of 
areas with the right conditions and position. The plane carries flares that 
produce silver iodide which makes the easiest to place and more efficient 
nucleation particles. Once the first ice particles form in the super cooled 
air they quickly form nucleation sites for more and soon it's raining.

Your granola bar is providing LOTS of nucleation sites for your super heated 
coffee so it boils. This can be VERY dangerous if your coffee is superheated 
more than a few degrees it won't just boil, it'll flash into steam 
violently.

Nucleation isn't the only way water can boil or freeze, a sharp jolt can 
bounce the molecules off each other forming nucleation sites on everything 
in the vessel. Suddenly the coffee cup just belches boiling water all over 
the place or a beer freezes to slush with a bump on the table. Beer freezes 
more slowly with cool feather shaped ice crystals because of the alcohol and 
CO2. Cool the beer to about 28-29f and set it on the counter with a bang. Do 
NOT bang a cup of super heated water on the counter though! Fog can occur in 
air both above dewpoint and below dew temp if subjected to a strong shock, 
pressure change, etc. like the wing vortices on heavy or fast manuvering 
aircraft or a BIG explosion say a nuke for an easy example. This is a 
non-nucleated phase shift as is a soda fizzing when you open it. Fizzing is 
caused by a rapid pressure reduction, same as Mt. St. Helens or Santorini. 
and is also a non-nucleated phase change. condensation means pessure rise 
and fizz means pressure drop.

On a side note; before the accident I would've had to look this stuff up for 
details even though I know what's going on. Now this stuff just rolls out, 
though I lose words, then the stupid things pop out if I just write them 
without trying to remember them. I guess there are balances for anything, 
mine seems to be better performance if I don't think about it. Well, sorta. 
<grin>

Jer
----- Original Message ----- 
From: "Ron Childers" <ron at munlaw.net>
To: "Blacksmithing List Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Monday, June 20, 2011 12:38 PM
Subject: Re: [TheForge] Harden & temper


>I thought that because when I take my coffee out of the microwave and
> dunk a granola bar it boils instantly....
>
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net
> [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Lynn and Susan
> Lang
> Sent: Friday, June 17, 2011 6:12 PM
> To: 'Blacksmithing List Sponsored by ABANA'
> Subject: Re: [TheForge] Harden & temper
>
> Ron
> As a sugarmaker I have experienced that sugar raises the boiling
> temperature of water(sap) also it lowers the freezing temp of the
> resulting Maple syrup.....
>
> lynn
>