Forgive me for being off the subject of shells, but I received this email
story which I suspect may be another urban legend.  I'm not smart enough to
disprove it--so I turn to you scientific types.  Seems to me when water
reaches 212 degrees F it will turn to a gas and produce steam, microwave or
not.  But what do you say?
-------------------
Subject:  Using the microwave

Read the attached.  I've done this a million times, but I bet I won't do it
again!!!

Anyone who uses a microwave oven to heat water should be made aware of this
safety risk.

About five days ago my 26-year old son decided to have a cup of instant
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 flew out into his face
due to the buildup 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
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 kettle.

Please pass this information on to friends and family.