Heat Reactive Fluid? Answered

+1
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.

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
http://www.youtube.com/watch?v=IBX7jZQJiPQ

Found via a search for the phrase "thermochromic powder"
http://www.google.com/search?hl=en&q=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:
http://www.qcrsolutions.com/Site/Thermochromic_Pigments,_Inks,_and_Plastics_|_QCR_Solutions_Corp.html
and this pdf:
http://www.qcrsolutions.com/Site/Thermochromic_Pigments,_Inks,_and_Plastics_|_QCR_Solutions_Corp_files/Thermochromic%20Pigments%20%7C%20Technical%20Datasheet%20%7C%20QCR%20Solutions%20Corp.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.

Amazing what you pick up as a 911 type :-)

A

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.

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,

Alex...

I am genuinely flattered. Thank you very much for the kind words.

-Jamie

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:
http://en.wikipedia.org/wiki/Wood%27s_metal#Related_alloys

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!