From: RMarks

Sent: Friday, August 26, 2005 8:51 AM

To: undisclosed

Subject: [Fwd: WATER IN MICROWAVE]

 

(I  did not know this, did you?)

 

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).

 

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. 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.