Subject: Microwave Heating Severe Warning!

My friendly 26-year old son 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 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 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. It is however a much safer choice to boil the water in a tea

Please pass this information on to friends and family.

General Electric's response:
Thanks for contacting us, Mr. Williams. 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.

I hope this helps.

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 that 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.