wg48temp9 - 13-9-2020 at 03:36
I am aware of super cooling and annealing in metals in particular steel. It is also easily observed in pet bottles.
I received a white fluorescent smoke dye that was a white powder with specks of red, a mixture confirming my thought that it would be a mixture of
three fluorescent dyes. However the powder showed no fluorescent effect. When I heated to powder in a test tube it melted to a transparent slightly
red liquid which did give of a whitish fluorescent smoke. I let the test tube cool and it remained a very viscous liquid. When I heated it again
particularly on the walls of the test tube small crystals and white spots formed which eventually melted again to a reddish transparent liquid.
I cooled the test tube this time in cold water and again a viscous liquid formed. About an hour later it was still transparent. However I noticed that
if the test tube was warmed by my hand white spots formed on the test tube walls and if left in my hand eventually the liquid solidified to a whitish
mass.
I assume the liquid was super cooled and the heat of my hand was sufficient to raise its temperature to its annealing point so that the crystals of
its ingredients were able to form and grow.
That raises the question, when trying to get a stubborn liquid to crystallize it may be better to keep its temperature closer to its melting point
than putting it in the freezer.
Watching the glowing wisps of smoke rising from the test tube under a black light looked strange as did the glowing patches on my fingers though
nothing could be seen when the room lights where turned on.
[Edited on 9/13/2020 by wg48temp9]
Junk_Enginerd - 19-9-2020 at 08:55
Interesting. I've noted some tendencies towards this with some ammonium nitrate that stubbornly refused to crystallise. Put it i the fridge. Nothing.
Then I gave up on it and put it on a room temperature shelf instead and in not too long, voila.
wg48temp9 - 20-9-2020 at 02:14
Where as an almost pure substance can super cool from a liquid state once some crystals form all the rest of liquid crystallizes as happens with hypo
or even a bottle of beer left in the freezer too long. As in this video https://www.youtube.com/watch?v=W0fURJg-K0A
But my dye is a mixture so even if small crystals of one or more of the ingredients does form at low temperatures they can not grow very large because
they are limited by diffusion. When the temperature is higher the diffusion is much faster this allows more of the compound that is crystallizing to
diffuse to the crystal and allows the other compounds to diffuse out of the way.