John Britt on thu 26 jun 03
Ivor,
I don't know if you remember the discussion on vaporization of salt? But in
refernece to that, I recently read in Monona Rossol's book on Health and
Safety the folowing:
"There is a common misconception that substances do not vaporize until they
reach their "vaporization point"- that is , their boiling point. Although
greater amounts of vapor are produced at higher temperatures, most
materials begin to vaporize as soon as they are liquid."
What is your take on this?
Since salt will is "absorbed" into the clay at around 1500F does that mean
that it has "melted"? So would it be appropriate to say that when you put
salt in a kiln it evaporates, vaporizes or volitalizes??
Looking for the appropriate term. Thanks for your help,
John Britt
Penland Clay
Lewis on fri 27 jun 03
"There is a common misconception that substances do not vaporize until they
reach their "vaporization point"- that is , their boiling point. Although
greater amounts of vapor are produced at higher temperatures, most
materials begin to vaporize as soon as they are liquid."
And indeed some (like iodine) sublimate - solid --> vapour. (e.g. iodine).
I would guess that anything with a smell must be emitting a vapour, albeit
most commonly from a liquid phase/solution I imagine - like tomatoes - it's
the moisture in the 'structure' of the tomato that carries the smell, but
with spices, say, I assume it's minute dust particles of the spices
themselves. Oh, stop rambling, Lewis: next time you smell dog poop, you'll
only realise what it is that's carrying the unique scent!
iandol on sat 28 jun 03
Dear Lewis,
I used to think this as well <solid --> vapour. (e.g. iodine).>> but one day I did the demo for the =
kids using a closed but not sealed flask, not to show sublimation, but =
to illustrate crystallisation from a gas phase.
So! What was that black liquid in the bottom of the flask where the =
specular violet crystals had been?
K & L.P151.. Iodine mp 113.6 deg C bp 184 deg C
Out on the Manitoba Plains I found out that under some weather =
conditions ice and snow sublime, just fade away without a trace of =
water.
Best regards,
Ivor Lewis. Redhill, South Australia
=20
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