Heating Water In A Microwave, Caution!
Microwaving Water!
: >
: >     A 26-year old man decided to have a cup of 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 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 w ater was not boiling, but suddenly 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 flown out into his face due to the build up 
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 is 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 pl aced in
: > the cup to diffuse the energy such as a wooden stir stick, tea bag, 
etc.,
: > (nothing metal).
: >
: >     It is however a much safer choice to boil the water in a tea kettle.
: >
: >     General Electric's Response:
: >
: >     Thanks for contacting us, I will be happy to assist you. The e-mail
: > that you received is correct. Micro waved water and other liquids do not
: > always bubble when they reach the boiling point. They can actually get
: > superheated and not bu bble at all. The superheated liquid will bubble 
up
: > out of the cup when it is moved or when something like a spoon or tea 
bag
: > is put into it.
: >
: >
: >     To prevent this from happening and causing injury, do not heat any
: > liquid for more than two minutes per cup. After heating, let the cup 
stand
: > in the microwave for thirty seconds before moving it or adding anything
: > into it.
: >
: >     Here is what our local science teacher had to say on the matter:
: > "Thanks for the microwave warning. I have seen this happen before. It is
: > caused by a phenomenon known as super heating. It can occur anytime 
water
: > is heated and will particularly occur if the vessel that the water is
: > heated in is new, or when heating a small amount of water (less than 
half
: > of a cup).
: >
: >     What happens is that the water heats faster than the vapor bubbles 
can
: > form. If the cup is very new then it is unlikely to have a small surface
: > scratches inside it that provide a place for the bubbles to form. As the
: > bubbles cannot form and release some of the heat has built up, the 
liquid
: > does not boil, and the liquid continues to heat up well past its boiling
: > point.
: >
: >     What then usually happens is that the liquid is bumped or jarred,
: > which is just enough of a shock to cause the bubbles to rapidly form and
: > expel the hot liquid. The rapid formation of bubbles is also why a
: > carbonated beverage spews when opened after having been shaken."
: >
: >     If you pass this on you could very well save someone from a lot of
: > pain and suffering
: >
: >
: >
: >
: >
: >
: >
: >
: >
:
:
:
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No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.405 / Virus Database: 268.11.7/432 - Release Date: 8/29/2006