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re hot pots from the microwave

updated fri 4 jun 99

 

judy motzkin on thu 27 may 99


My understanding of microwave ovens is that the
microwaves excite the molecules of water present causing
them to vibrate and therefore heat up. I suspect that
the too hot to handle mugs are of a porous clay. If the
water has not completely evaporated out after use or
washing, that water heats up with your food making the
pot hot.

Judy
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susanford on fri 28 may 99

I have noticed that earthernware heats up much hotter in
the microwave than stoneware or porcelain. I have
commerical and handmade expamples of both, and it's the
earthernware that needs ovenmitts!

Susan

> My understanding of microwave ovens is that the
> microwaves excite the molecules of water present causing
> them to vibrate and therefore heat up. I suspect that
> the too hot to handle mugs are of a porous clay. If the
> water has not completely evaporated out after use or
> washing, that water heats up with your food making the
> pot hot.
>
> Judy
> _________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.com address at http://mail.yahoo.com
>
>
---
Susan K. Ford
Norman, Oklahoma
http://www.clueless.norman.ok.us/sf/rerhome.htm

Gary Elfring on sat 29 may 99

>My understanding of microwave ovens is that the
>microwaves excite the molecules of water present causing
>them to vibrate and therefore heat up. I suspect that
>the too hot to handle mugs are of a porous clay. If the
>water has not completely evaporated out after use or
>washing, that water heats up with your food making the
>pot hot.

Your understanding of how food heats up is correct, but
the hot handle is not caused by water heating.

Microwaves react with a number of different molecules
and transfer energy to those molecules. Water is a
*medium* microwave "reactant". Metals are very high
microwave "reactants".

If you read the instructions for your microwave, you will
see a note that tells you to never put metal into your
microwave. (You can actually burn out the microwave oven
by leaving a spoon in it, while it is on.)

So why does the cup handle get so hot? If your glaze
contains too much of the right kind of metal, then the
glaze itself will heat up, using most of the microwave
energy in the oven. Since the cup contains water, and
since that water didn't get very hot (the metal in the
glaze stole most of the microwave energy), the water is
cool. Of course the cool water is touching th hot glaze
everywhere *except* on the handle. The hot glaze heats
the water in the cup, and the cup and the water end up
fairly close in temperature. (Water temperature goes up
and glaze temperature goes down.)

But the handle doesn't have any water touching it to cool
it down. So the handle stays at wathever temperature it
got to. Hence the hot handle.


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Philip Schroeder on sun 30 may 99

In a message dated 99-05-27 22:49:20 EDT, you write:

<< My understanding of microwave ovens is that the
microwaves excite the molecules of water present causing
them to vibrate and therefore heat up. I suspect that
the too hot to handle mugs are of a porous clay. If the
water has not completely evaporated out after use or
washing, that water heats up with your food making the
pot hot. >>

I think that is correct about microwave ovens/molecules but an open clay
body, no matter how long it sits in the cupboard to dry always has some
moisture in it. It will get hot before the liquid/food. I don't know that
the pot will be adversely affected, but it isn't good for the fingers. I do
some low temp,^3, stoneware that gets very tight and I don't get any heating
before the food. But I have tested a terra cotta body at ^3(where it has low
absorption) and the vessel gets hot.
My guess is that the optimal clay body/cone for microwave ware has been
discussed here before, maybe someone has more info than I.
Phil Schroeder in Chicago

holmstrom.ceramco@tidvatten.pp.se on sun 30 may 99

<19990528155855267.aac30-@mail.inil.com@localname> wrote:
Original Article: http://www.egroups.com/group/clayart/?start=45593
> ----------------------------Original message----------------------------
> >My understanding of microwave ovens is that the
> >microwaves excite the molecules of water present causing
> >them to vibrate and therefore heat up. I suspect that
> >the too hot to handle mugs are of a porous clay. If the
> >water has not completely evaporated out after use or
> >washing, that water heats up with your food making the
> >pot hot.
>
> Your understanding of how food heats up is correct, but
> the hot handle is not caused by water heating.
>
> Microwaves react with a number of different molecules
> and transfer energy to those molecules. Water is a
> *medium* microwave "reactant". Metals are very high
> microwave "reactants".
>
> If you read the instructions for your microwave, you will
> see a note that tells you to never put metal into your
> microwave. (You can actually burn out the microwave oven
> by leaving a spoon in it, while it is on.)
>
> So why does the cup handle get so hot? If your glaze
> contains too much of the right kind of metal, then the
> glaze itself will heat up, using most of the microwave
> energy in the oven. Since the cup contains water, and
> since that water didn't get very hot (the metal in the
> glaze stole most of the microwave energy), the water is
> cool. Of course the cool water is touching th hot glaze
> everywhere *except* on the handle. The hot glaze heats
> the water in the cup, and the cup and the water end up
> fairly close in temperature. (Water temperature goes up
> and glaze temperature goes down.)
>
> But the handle doesn't have any water touching it to cool
> it down. So the handle stays at wathever temperature it
> got to. Hence the hot handle.
>
>
> Elfring Soft Fonts, Inc. http://www.elfring.com
> http://www.barcodingfonts.com http://www.micrfonts.com
> Bar Codes, MICR, Signatures, plus popular TrueType fonts and clip art.
>
> Like H2O the SiO2-molecule is slightly di-polar, ie it has a positive
and a negative end which means it, like water, becomes excited in a micro-
wave field - the piece gets hot. So, keep trying out clays/bodies - preferably w
//nisse
http://hem3.passagen.se/keram/

Ron Roy on thu 3 jun 99

I don't believe this is the whole story - reading this would lead to the
beliefe that a white glazed pot - made of clay not vitrified enough to
exclude water - would not get hot in a microwave. It will as many have
attested to in posts on ClayArt.

It would not be hard to verify this by doing some experiments in your own
microware oven. Just be sure to have a vessel contaning some water - in the
oven so it will not be damaged. You could start with some bisqueware - some
dry some wet.

RR


>Microwaves react with a number of different molecules
>and transfer energy to those molecules. Water is a
>*medium* microwave "reactant". Metals are very high
>microwave "reactants".
>
>If you read the instructions for your microwave, you will
>see a note that tells you to never put metal into your
>microwave. (You can actually burn out the microwave oven
>by leaving a spoon in it, while it is on.)
>
>So why does the cup handle get so hot? If your glaze
>contains too much of the right kind of metal, then the
>glaze itself will heat up, using most of the microwave
>energy in the oven. Since the cup contains water, and
>since that water didn't get very hot (the metal in the
>glaze stole most of the microwave energy), the water is
>cool. Of course the cool water is touching th hot glaze
>everywhere *except* on the handle. The hot glaze heats
>the water in the cup, and the cup and the water end up
>fairly close in temperature. (Water temperature goes up
>and glaze temperature goes down.)
>
>But the handle doesn't have any water touching it to cool
>it down. So the handle stays at wathever temperature it
>got to. Hence the hot handle.

Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849

Web page: http://digitalfire.com/education/people/ronroy.htm