Paul Taylor on tue 8 feb 00
Dear Ivor.
I enjoyed your essay on porcelain an I agree with your sentiments. I
shall show it to my students as an example of someone challenging opinions
that are taken for granted.
However. Today I did your experiment.
Well ground salt was cooled to -20c and also two receptacles.
Frost was collected from the inside of the plastic freezer tray since it is
nearly pure water and it is difficult to grind ice small enough without the
pressure raising the temperature and melting it.
I put the cooled salt and the ice into one receptacle and the ice into
another I mixed both with a plastic spoon and then left them in the fridge
ice box aprox -7c .
When I went back to the fridge the mixture had melted the ice had not.
Was there fault in my methodology or Is this a quantum affect. Since I,
and the local traffic authority expect ice to melt after the addition of
salt - it does. Of course this does not necessarily mean Eutectics is at
work but I would need convincing otherwise.
I have made the silica alumina lime eutectic By adding whiting to clay and
although it did not melt to a glass at the predicted temperature it turned
into a glass at aprox 1200c but there again I did not make notes and can
not promise that the temp was above that. Since the melting point of silica
,alumina and calcium is above 1200 I presume Eutectics is at work here.
Paul T
----------
>From: "I.Lewis"
>To: CLAYART@LSV.UKY.EDU
>Subject: Eutectics and the Salt Ice Analogy
>Date: Thu, Dec 23, 1999, 7:01 pm
>
>----------------------------Original message----------------------------
>------------------
>
>Special thanks to our Moderators for the exceptional effort they have made on
>our behalf during the past year and my best wishes and seasonal greetings to al
>cyber companions, contributors and readers of Clayart.
>
>
>Recall, the prediction is that a liquid will form because Salt and Water combin
>to make a Eutectic. This example has been used as an analogy to explain why our
>glazes melt and why metal oxides which have extremely high melting temperatures
>liquefy so readily at the lower temperatures to which we fire our kilns.
>
>Awaiting some sort of news,
>
>Ivor Lewis.
Earl Brunner on wed 9 feb 00
Am I missing something here? I'm not sure what the point is. I have always
understood salt to act upon ice to liquefy the frozen water, and make a super
cooled liquid. I don't know the physics of it. But I'm pretty sure that it
doesn't give off much heat in the process. If it did my ice cream maker
wouldn't work. I don't think of it as melting, but liquefying. How would
this apply to eutectics? Of course I never really understood eutectics......
Paul Taylor wrote:
> ----------------------------Original message----------------------------
> Dear Ivor.
>
> I enjoyed your essay on porcelain an I agree with your sentiments. I
> shall show it to my students as an example of someone challenging opinions
> that are taken for granted.
>
> However. Today I did your experiment.
>
> Well ground salt was cooled to -20c and also two receptacles.
>
> Frost was collected from the inside of the plastic freezer tray since it is
> nearly pure water and it is difficult to grind ice small enough without the
> pressure raising the temperature and melting it.
> I put the cooled salt and the ice into one receptacle and the ice into
> another I mixed both with a plastic spoon and then left them in the fridge
> ice box aprox -7c .
>
> When I went back to the fridge the mixture had melted the ice had not.
>
> Was there fault in my methodology or Is this a quantum affect. Since I,
> and the local traffic authority expect ice to melt after the addition of
> salt - it does. Of course this does not necessarily mean Eutectics is at
> work but I would need convincing otherwise.
>
> I have made the silica alumina lime eutectic By adding whiting to clay and
> although it did not melt to a glass at the predicted temperature it turned
> into a glass at aprox 1200c but there again I did not make notes and can
> not promise that the temp was above that. Since the melting point of silica
> ,alumina and calcium is above 1200 I presume Eutectics is at work here.
>
> Paul T
> ----------
> >From: "I.Lewis"
> >To: CLAYART@LSV.UKY.EDU
> >Subject: Eutectics and the Salt Ice Analogy
> >Date: Thu, Dec 23, 1999, 7:01 pm
> >
>
> >----------------------------Original message----------------------------
> >------------------
> >
> >Special thanks to our Moderators for the exceptional effort they have made on
> >our behalf during the past year and my best wishes and seasonal greetings to
> >cyber companions, contributors and readers of Clayart.
> >
>
> >
> >Recall, the prediction is that a liquid will form because Salt and Water comb
> >to make a Eutectic. This example has been used as an analogy to explain why o
> >glazes melt and why metal oxides which have extremely high melting temperatur
> >liquefy so readily at the lower temperatures to which we fire our kilns.
> >
> >Awaiting some sort of news,
> >
> >Ivor Lewis.
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Bryan on wed 9 feb 00
To get a reasonable parallel I'd guess that it would require an
experiment that used two fluxes and water. Maybe calcium chloride and
sodium chloride could be added in a line blend and the freezing temps
(or melting point of the mix) compared.
Bryan
-----Original Message-----
From: Paul Taylor
To: CLAYART@LSV.UKY.EDU
Date: Tuesday, February 08, 2000 1:17 PM
Subject: Re: Eutectics and the Salt Ice Analogy
>----------------------------Original
message----------------------------
>Dear Ivor.
>
> I enjoyed your essay on porcelain an I agree with your
sentiments. I
>shall show it to my students as an example of someone challenging
opinions
>that are taken for granted.
>
>
> However. Today I did your experiment.
>
> Well ground salt was cooled to -20c and also two receptacles.
>
> Frost was collected from the inside of the plastic freezer tray
since it is
>nearly pure water and it is difficult to grind ice small enough
without the
>pressure raising the temperature and melting it.
> I put the cooled salt and the ice into one receptacle and the ice
into
>another I mixed both with a plastic spoon and then left them in the
fridge
>ice box aprox -7c .
>
> When I went back to the fridge the mixture had melted the ice had
not.
>
> Was there fault in my methodology or Is this a quantum affect.
Since I,
>and the local traffic authority expect ice to melt after the addition
of
>salt - it does. Of course this does not necessarily mean Eutectics is
at
>work but I would need convincing otherwise.
>
> I have made the silica alumina lime eutectic By adding whiting to
clay and
>although it did not melt to a glass at the predicted temperature it
turned
>into a glass at aprox 1200c but there again I did not make notes and
can
>not promise that the temp was above that. Since the melting point of
silica
>,alumina and calcium is above 1200 I presume Eutectics is at work
here.
>
> Paul T
>----------
>>From: "I.Lewis"
>>To: CLAYART@LSV.UKY.EDU
>>Subject: Eutectics and the Salt Ice Analogy
>>Date: Thu, Dec 23, 1999, 7:01 pm
>>
>
>>----------------------------Original
message----------------------------
>>------------------
>>
>>Special thanks to our Moderators for the exceptional effort they
have made on
>>our behalf during the past year and my best wishes and seasonal
greetings to al
>>cyber companions, contributors and readers of Clayart.
>>
>
>>
>>Recall, the prediction is that a liquid will form because Salt and
Water combin
>>to make a Eutectic. This example has been used as an analogy to
explain why our
>>glazes melt and why metal oxides which have extremely high melting
temperatures
>>liquefy so readily at the lower temperatures to which we fire our
kilns.
>>
>>Awaiting some sort of news,
>>
>>Ivor Lewis.
>
ferenc jakab on thu 10 feb 00
Earl,
Hope this helps; as I understand a eutectic reaction occurs with the mixing
of two materials to create a material that melts at a lower temperature than
either of the two original material's melting points.
Salt added to water engenders an endothermic reaction which cools the water,
hence its use in icecream machines. Whether this reaction can be called
eutectic I don't know, though the salt does lower the freezing point of the
water, a kind of reverse "eutectic" from that described above.
???????????
Feri.
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