Microwave Dangers

OK - I know this is a crock, but I lack the technical know-how to explain why. Can anyone help me?

(I received this in an inter-office group forward :slight_smile:

Subject: Microwaving Water to Heat it Up

I feel that the following is information that any one who uses a microwave
oven to heat water should be made aware of.

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.

Um… it’s not a crock. There was a thread about this not too long ago, but I can’t find it. I kinda doubt everyone who tries it will get first degree burns, but I’ve had it happen to me. Put a mug of water into microwave - nuke for 3 minutes - take water out - add tea bag - as soon as tea bag touches the water it starts into an explosive boil, spills out of the glass, and all over the counter. If you were holding the mug, you’d be quite burned.

I meant - I’ve had the explosive boil thing happen to me, NOT the first degree burns! Doh!

I’m assuming the water in the cup is getting superheated. That is, its temperature is higher than the boiling point but it hasn’t started boiling because there are no small disturbances or nucleation sites for the bubbles to form. When you jiggle the cup or put a teabag in it creates the sites and the process takes off explosively.

I guess it’s possible. I certainly wouldn’t call Athena a liar. I don’t think it happens very often. And yes, adding a (wooden) stirring stick would provide the rough surface required for the initial bubbles to form.

I suppose the best way to handle it is to be suspicious if the water isn’t boiling when you’d expect it to, and act with appropriate care. Getting a faceful of scalding water would take a little extra effort IMHO – you’d have to do things just right to get the whole cup to blow up at just the moment you were looking straight down on it.

“To do her justice, I can’t see that she could have found anything nastier to say if she’d thought it out with both hands for a fortnight.”
Dorothy L. Sayers
Busman’s Honeymoon

What does microwaving have to do with it?
Would this be equally possible with a gas range, for example? I mean, if the problem is a lack of nucleation sites for bubbles …
now that I think about it, though, you’d boil water on a stove in something unlikely to be as smooth as a coffee cup, more likely it’d be an old pan with pits and stuff…

I think it has to do with the surface of the container, because it happens to me all the time with one particular mug. This thing is some sort of hard plastic, I think. It’s transluscent, almost looks like thick glass but I don’t think it is. It never boils when it’s in the microwave, only when I add the tea bag.

pluto nailed what went on with the water. I’m wondering about the burns; IIRC it’s 3rd degree burns that scar. Is that not correct?

We used to do this in the lab at UCSD all the time. Put in little rocks, called boiling stones, that make the water boil cause they holes in them or something. Course, being deaf, I didn’t hear that you are supposed to add them BEFORE heating the water, so I added them after and kablooie!

Second Deg burns shouldn’t scar. Did you know there are 6th deg too? Charcoal, gross.

6th Degree? Quite a few years ago, I was shooting a job on the burn ward at Denver’s Children’s Hospital. Apparently it is THE critical burn center for that part of the USA.
I was told something interesting by one of the nurses. She said that the whole “Degrees” thing was falling by the wayside,and they were called " Minimal Thickness, Partial Thickness, and Full Thickness" burns.
Anyone have dope on this> The shoot traumatized me for weeks after, and ruined a partnership that was about 9 years old at that point. I respect nurses who work that unit beyond words.
Full thickness, I should add, indicated that all skin was gone, and that muscle tissues had burned down badly.


" If you want to kiss the sky, you’d better learn how to kneel. "

If this ‘blowing up’ of water heated in a microwave is “a fairly common occurrence and water (alone) should never be heated in a microwave oven”, anyone up for a class action suit against the microwave popcorn companies?

sdimbert, were there any details in the e-mail (name of person who wrote it, name of son, date, city/state, name of hospital, name of doctor, etc.) that could be used to pinpoint the story? If the story you posted is exactly as you received it, it’s likely that it’s another UL.

“sdimbert, were there any details in the e-mail (name of person who wrote it, name of son, date, city/state, name of hospital, name of doctor, etc.) that could be used to pinpoint the story? If the story you posted is exactly as you received it, it’s likely that it’s another UL.”

Of course, there was no real information - that’s what made me think it was a crock in the first place; it read a lot like the old Chocolate Cookie Recepie email.

(BTW, what is a “UL”?)

“UL” = “urban legend.”

Basically a myth that a lot of people have heard.

Typically, they don’t have specific names or places, and when they do, they’re made up.

If you’re not familiar with them, plug in “snopes” on your search engine. That site tracks them, and gives the “straight dope” on them.

It’s possible the water was above boiling point when he took it from the oven & a dust particle or hair, etc, fell into it, which would cause the boil to occur.

Stick a toothpick in something inert like clay, put it in the microwave oven, for less than one minute, you get a wonderful gaseous cloud.

I forgot to add, you must light the toothpick & let it burn down to black & no flame before putting it in the oven.

Cecil says it can happen.

Yeah, but that’s after someone has added Sweet 'n Low (or sugar, or salt, etc.). The story in the OP states that he removed the cup from the oven, looked in the cup and had the water ‘blow up’ in his face. Nothing is mentioned about adding the instant coffee (or anything else), implying that there was no trigger for the reaction.

Your Official Cat Goddess since 10/20/99.

“We are here! You are saved!” --R. & F.

Kat, yes but even a hair could set it off.

Shaking or jarring the liquid can trigger the boiling process in a super saturated liquid.
The OPs son may have been fairly gentle with the cup until he was looking into it, at which point he may have “clinked” his ring against the cup or some other physical disturbance.
I have purposely super saturated containers of water in the microwave, and have found that one of the surest ways to trigger the boiling process is to “ring” the cup like a bell. This seems to cause sound waves in the liquid that will cause nucleation and rapid boiling.


“Misers get up early in the morning; and burglars, I am informed, get up the night before.”~~*G.K.Chesterton *

Here’s the thread from earlier…

I wish knew about this before because I just blew up the microwave!
I was trying to heat up the water in one of my daughter’s bottles (to clean it, not for drinking!)and after only about 1 min on high, KABLAM!!! the microwave door exploded open, the bottle went flying, and water went everywhere! No one was hurt thank goodness! Wouldn’t you think there would be warnings about this???