RE: H2O Microwave Criticality

["Neil, David M" <neildm@id.doe.gov>]

(HOW MUCH OF THIS IS TRUE??)  Overall, I suspect it is an "Urban Legend".  

Water heated in a microwave WILL develop hot spots, even before reaching an
overall boiling temperature, which will cause foaming when a solid is added.
Instant coffee is particularly good for doing this, for some reason.
However, for the cup and water to both be so clean that no nucleation sites
were present to a degree allowing a high energy supercritical state, in a
casual environment, boggles the mind. 

A more likely scenario is this:  when the coffee was added, the water
bubbled enough to overflow on the hand holding the cup, scalding it.  A
reflexive twitch would then take care of scattering the contents of the cup.

Dave Neil
neildm@id.doe.gov

> -----Original Message-----
> From:	Tad Blanchard [SMTP:Tad.M.Blanchard.1@gsfc.nasa.gov]
> Sent:	Monday, January 24, 2000 2:24 PM
> To:	Multiple recipients of list
> Subject:	H2O Microwave Criticality
> 
> I came across the following and had to post it here for everyone to enjoy:
> 
> 
> "Subject: Microwaving Water
> 
> I received the following from my cousin who works at the CDC in Atlanta.
> It's worth sharing. I feel that the following is information that any one
> who uses a microwave oven to heat water should be made aware of.  About
> five days ago my 26-year old son decided to have a cup of instant coffee.
> He took a cup ... <snip>
> 
> (HOW MUCH OF THIS IS TRUE??)
> 
> 
> 
> Tad Blanchard                   NASA-Goddard Space Flight Center
> Sr Health Physics Tech           Code 205.9, Greenbelt, MD 20771
> Parallax, Inc                                Phone: 301-286-9157
> A Member of the OHI Team                     Fax:   301-286-1618
>             mailto:tmblanch@pop200.gsfc.nasa.gov
> http://gsfc-aphrodite.gsfc.nasa.gov/205/205-2/Health/RADPROT.HTM
> 
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