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
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.. Microwaved 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.'

If
you pass this on
you could very well save someone from a lot of pain and
suffering. 

 
 
"We don't
know who we are until we see what we can do"