*As received* **
** *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 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 **Microwaving Water! **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.* -- * േസ്നഹേത്താെട ജഗ്ഗു :) With Love JaGGu :) http://lifexperiments.blogspot.com/* --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "MTA0406" group. To post to this group, send email to mta0406@googlegroups.com -~----------~----~----~----~------~----~------~--~---
