Heat Reactive Fluid?

I've seen metal once that was reactive to heat, it changed color when heat was applied and changed back afterwards (funny note it was used in a urinal) I'm wondering if a liquid form of this exists ? 

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orksecurity6 years ago
May just have been a liquid-crystal finish on the urinal's surface.
like the stick-on thermometers on aquariums

The author's product in question is a psychological trick to convince drunk people to actually urinate IN the urinal by making a game of it.

Same with any time you've seen an image of a fly printed on the porcelain. Give a wandering mind a target, and they're less likely to piss on the floor XD

As for a liquid form - I know you can get Thermochromic powder which can be added to paint to make a white/black change, but the rainbow colour change is really down to liquid crystal as you say.
Douglerful (author)  frollard6 years ago
hmmm, what i was planning to do was use in a liquid cooling rig on a computer, would be really interesting to literally see the "heat" move in the system. Is there any way this could be mimed? Perhaps a powder in the water?
Have you seen this one?

SolarColorDust.com - Thermal-Dust! Thermochromic Powder Pigment Demonstration

Found via a search for the phrase "thermochromic powder"
You might have noticed the SolarColorDust pages have a lot of "Ooh-Ahh! Look at the pretty colors!", but are very much lacking in technical data. 

Regarding questions about what that powder actually is, and what its weaknesses are, I found this:
and this pdf:

Anyway, to me it looks like this stuff might work for your PC cooling toy, for some amount of time.  They quote a "shelf life" of 12 months. In addition to this, the pdf tells you other conditions to avoid: UV light, prolonged exposure to temperatures greater than 50C, polar solvents... shear from milling will break the microcapsules, and um... don't feed 'em after midnight.  You'll be sorry if you do. ;-)
The powder exists - search for thermochromic pigment. you MIGHT be able to safely add it to your coolant.
iceng frollard6 years ago
Amazing what you pick up as a 911 type :-)

frollard iceng6 years ago
I'm an inquisitive type who happens to have a career 911ing :) I blame google, wikipedia, instructables, and stumbleupon for a majority of my knowledge.
iceng frollard6 years ago
I rather look at your life with envy of your wondrous future coming to you.
As doctor Zarkov in Flash Gordon you populate, distill and organize knowledge's
odd bits with compassion, how wonderful to fill a brain this way.
Best Regards,

frollard iceng6 years ago
I am genuinely flattered. Thank you very much for the kind words.


there is. its called LCD it stands for Liquid Crystal Display its inside of screens of older phones the screen contains a really thin sheet of liquid crystal and is electrically separated by a grid of insulating material that separates the sheet into millions of pixels that are connected to two sets of wire arrangements that trigger each pixel similar to a times table chart were the two numbers make up the answer(the two numbers are the wires and the answer is the pixel) but its probably not enough to collect for your use. there is some inks that have this effect when you add heat you can also make a ferro fluid. the gas helium also contains these properties but requires additional technology to use it in the light spectrum and is used in thermal vision equipment

iceng6 years ago
Yea...... That is weird,
I once had this spoon that puddled in a hot tea.
Someone told me it was woody metal.
Nut sure though :-þ
Have a good one.

kelseymh iceng6 years ago
Ah, yes. Gallium. Back in the days before toxicity was something people paid attention to :-)
Not necessarily Gallium. There are bunch of low melting point alloys, of which "Wood's Metal", an alloy of bismuth, lead, tin, and cadmium, is one example. Wood's, Rose's, Field's... There's a list of several of them here:
Indeed! Iceng PM'ed me about it, and I found that article to be quite interesting. Not being a metallurgist, I had never encountered the term "eutectic" before. It's always great to learn something new!
Feeding the phrase "temperature sensitive paint" unto Google, gives some good results:

Wikipedia article on Thermochromism

Temperature Sensitive Paints - Capgo