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Re: Hot water in microwave



I think I have the answer: Until the microwave oven, it was unusual for
"people" to heat liquids in glass. The usual utensils have nucleating
sources which make it difficult to superheat. With the microwave most
don't use metal sauce pans in which to heat. This explains the sudden rash
of experience with superheated liquids. I suspect that putting any rough
solid, especially a powder (instant coffee), in a superheated liquid will
cause explosive vaporization.

bc

Rick Swanson wrote:

I came across the report below about hot water "blowing up" after being
microwaved. Does not make sense to me. Anyone have information about
such a thing?


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 of water and put it in the microwave to heat it up
(something that he had done numerous times before). I am not sure
how
long he set the timer for but he told me he wanted to bring the
water
to a boil. When the timer shut the oven off, he removed the cup
from
the oven. As he looked into the cup he noted that the water was
not
boiling but instantly the water in the cup "blew up" into his
face.
The cup remained intact until he threw it out of his hand but all
the
water had flew out into his face due to the buildup of energy.
His
whole face is blistered and he has 1st and 2nd degree burns to his

face which may leave scarring. He also may have lost partial
sight in
his left eye. While at the hospital, the doctor who was attending
to
him stated that this a fairly common occurrence and water (alone)
should never be heated in a microwave oven. If water is heated in

this manner, something should be placed in the cup to diffuse the
energy such as a wooden stir stick, tea bag, etc. It is however a
much
safer choice to boil the water in a tea kettle. Please pass this
information on to friends and family.


Cheers,

Rick

--
Richard E. Swanson, Ph.D. (910) 695-3715
Professor of Physics FAX: (910) 695-1823
Dean of Instruction
swansonr@email.sandhills.cc.nc.us
Sandhills Community College
Pinehurst, North Carolina 28374 "He who laughs, lasts."