Hey guys, I just want to pass this story that I got in my e-mail and if you pass this on, you could very well save someone from a lot of pain and suffering.
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 water 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 placed in the cup to diffuse the energy such as a wooden stir
stick, tea bag, etc.., (nothing metal).
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 bubble 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 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 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."