23 Candles that change color when their lit? You probably thought I was going to add some metals to them and the flame would go from green to red to yellow etc., right? Pffft. Fuck that metal shit. I’m an organic chemist and therefore I shun the use of metals – SHUN THEM. SHUN THEM STRAIGHT TO HELL. Unless I need to use one to do some reaction… then they’re welcome. BUT THEN IT’S BACK TO SHUNNING!
A decidedly organic solution is to use the properties of fluorescence such that when the candle is lit it likewise lights up a fluorophore which, hopefully, is a different color than the flame or the wax surrounding it. To accomplish this we need a few fundamental things: 1) An organic dye that isn’t too horribly toxic that doesn’t produce yellow/orange light when it fluoresces. 2) A medium (i.e. the wax) that is transparent and easy to work with. 3) a container within which you shall burn your mighty candle.
Above you see all three solutions (that I present for this little exercise). I shall burn anthracene in GelWax inside a 20mL scintillation vial. The first step is to melt your gelwax and add the anthracene, which I have
made up as a saturated toluene solution for easy adding pleasure. After you melted your wax on a hotplate, you are free to add your toluene solution of anthracene. You want to bubble off the toluene so that when you go and light up the candle you aren’t totally overwhelmed by stinky model-glue smell.
This process takes a minute, so you’ll want to be patient. Once the bubbling stops, however, you can pour the waxy goodness into your vial with a wick positioned inside it.
You can make clever use of your three pronged clamps by holding a wick that you presumably purchased at the same craft store that you found your wax at. The drying process then must occur… and you wait and wait and wait.
Now, I’ve never made a candle in a little vial like this before and, after having done it, I recommend two things from this whole experiment. One: Don’t use 20mL vials. They are too fucking small. You’ll see below I had to break the rim off mine to keep the wick lit. Two: don’t use anthracene. Antrhacene is a pretty color and everything, but in reality you want something that is excited by yellow/orange light – not UV light, which (as it turns out) candles put out almost none of. So, indeed, when I went to light this shit up I really got disappointed in that I saw no blue coming out of my vial – only after I shut the lights out and turned the exposure setting on my camera way the fuck up and then photoshopped the flame down so it didn’t look as lit up as an Englishman in Prague (limy bastards piss on everything) was I able to obtain the results below. It’s certainly not a “naked-eye” thing.
It’s not spectacular. What needs to happen is a different dye, specifically a red emitting dye that absorbs those pretty fire colors and the only one of which I know to be simple enough to make are squaraines, which simply involve refluxing squaric acid with N,N-dialkyl-aniline with some sieves. Squaric acid can be pricey, so you’ll have to check with your boss if you want to purchase this shit. As for me, I found a retailer on the intertubes that actually sells the shit to anyone. The anline is cheap, no one will miss it. Of course, if you have the dye just handy, that makes the whole thing that much simpler. Turns out I have a dye on hand (though not the magical squaraine) and in enormous quantities because another lab, which did research on this kind of shit, cleared out and we inherited their chemicals including a jar of “Cy5.5.” Figuring one dye was as good as any other, I dissolved it up in good ol’ chloroform and tossed it into the molten wax. I then dumped my hot load into a large bowl I purchased from the craft store and set the wick and let it sit for a while. To summarize:
Anyway, after all that sitting and waiting for the fucking wax to solidify I ended up with a pretty awesome candle. You can see the results below. The dye appears green but sure enough it fluoresces red. This will make an asskickity gift for someone who needs to be reminded HOW IMPORTANT I AM TO THE LAB and how awesome I am at the same time. (I do *hearts* my boss but sometimes our “visions and directions” of how my research should go leads to tense relationships. I like to think that by buying his affection like this I can remain in those good graces well after he starts reviewing my own future grants.)
Now that’s some pretty science right there.
Now, to cover my ass: These candles are never to be lit outside of a properly constructed and certified fume hood. Burning anthracene and aromatic compounds in general is a bad idea and produces a gross black flame of cancer. Toluene smells bad and that green candle was made with more chloroform than I’d like to admit. They’re (probably) perfectly safe to set on a shelf and enjoy the fuck out of; however, I take no responsibility for your future cancers. (I have it on good authority that the long wavelength dyes don’t last too long on the shelf – even in wax.)
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Asskickity is my favorite word.
you need a wick that burns at 300 nm, then the anthracene and cy candles will look rad!
Are there any metals that, when oxidized (which is what I assume to be the source of the color in a flame w/ some metal like copper in it), emit UV light? That doesn’t really seem totally unlikely.
Uhhh…. I’m pretty sure it’s not oxidized. Just a simple excitation of a valence electron. Anyways, the metal you’d be looking for has a filled valence sub-shell. You’d probably need to put more energy into it than a simple candle can provide. Off the top of my head, I thought that mercury would do the trick since it’s just right as a heavy metal where the energy difference between sub-shells is not too great. Cadmium might work better if my ‘off the top of my head’ measurement is off a bit. Laser and Analytical people should know their wavelength sources better than me.
Ah, here we go. Looks like I was sort of right. It might be difficult to set this up in a candle as it doesn’t supply enough power. Plus, you don’t really want to burn mercury I guess. Oh well, as long as it’s in a fumehood, everything will be o.k.
http://en.wikipedia.org/wiki/C.....scent_lamp
Like I say, I SHUN metals and it’s been 6 years since I took inorganic chemistry of any sort. I suppose that may have been mentioned, but it struck me as more likely a chemical transformation was occurring than an electronic one – but I’m just trying to excuse my ignorance. So you’ll have to forgive me.
Here’s another naive (or stupid) question, I suppose. Chemically, what’s the difference between promoting an electron to a higher energetic state with fire vs. doing it with a direct current of electrons as in that CF bulb? Obviously the first one is a thermal process, but what would you call the second one and is there a way to correlate temperature to wattage to figure out how hot one would need to make Hg to become luminescent?
Well, from what I remember from my quantum class, what the alcohol hasn’t killed off in my brain seven years later, is that there is a way to correlate temperature to frequency of photons emitted. This is known as Blackbody Radiation and is the reason why the sun looks yellow. Also why the stove element is red and the candle is yellow. Hotter stars than the sun look blue for this reason.
http://hyperphysics.phy-astr.g.....d6.html#c5
Now, you can use the Stefan-Boltzman law to correlate energy emitted by a radiator such as a candle, to wattage.
http://hyperphysics.phy-astr.g.....Frame.html
A blackbody radiator that is a candle is going to be pretty inefficient at transferring energy at high frequencies. A lot of the photons are going to get wasted as visible light and heat. But to figure out what temperature you need to excite mercury, you’d need to use Planck’s formula assuming you know the frequency. Then you use S-B to figure out the wattage.
Mercury gas is a pretty poor blackbody radiator. I guess in the lamp, you’re acting on the mercury vapor very efficiently (inelastic electron scattering) to cause emission at just two UV frequencies, whereas what you were thinking of would be a really hot candle that acts inefficiently by radiating a lot of high energy photons (and others that do nothing) and exciting mercury in the process. Although, I suppose if you had mercury in the wick of the candle, some radicals that are formed there could do the trick but I doubt it. The wick wouldn’t get hot enough to work the other way as well. I like milkshake’s idea better.
Hmmm… hopefully a resident physicist will show up to corroborate my thoughts.
Magnesium metal burns brilliant bluish-white, and there is a significant UV component in the produced light. I know this from a dude who was playing with magnesium powder+oxidant flash mixtures, and got one pretty big batch by accident ignited too close. He saw what he thought was afterimage but the “afterimage” was there the next morning and his eyes hurt like hell. Turns out he damaged his retina by the UV produced in the flash, and spent some time in eye hospital.
Welders have to wear dark goggles for the same reason.
Yes. A candle with a magnesium wick. Marginally better than the one with the mercury soaked one.
Fucking 133+, dude. I want one. Seeing as I smoke a pack of cigarettes everyday, I’m not particularly concerned about the effect of any fumes it might give off. Besides, if you have you wick trimmed properly, the combustion should be fairly complete.
Here’s a question, though: would there be anyway to make it a free-standing candle, assuming you could find a candle mold? The candles-in-glass kind of suck, as they tend to extinguish themselves after a while.
Free standing? Possibly. It would obviously require a mold to pour the wax into – something my metallurgical skills aren’t quite up to. I’ve never seen a hard enough transparent wax, but assuming you can find something that’s rather translucent, you would most likely be able to do that. Once the candle burns down into the wax, you would likely see a nice red glowing core when lit and just a green wax when unlit.
8000 MW PEG + aluminum foil mold?
You know, I’ve always thought that seduction by hood fluorescent light and candles would be so sexy. I guess it’s too bad for me that I never came up with that idea in grad school (snicker), although our lab’s hoods were not clean enough that I would want to rub my hands on them, much less anything else, and knocking over the neighbor’s piranha solution could be a slight problem.
The problem might be that I can think of people who might actually have used your candles as directed. (shudder).
I’m guessing that seduction by hood light doesn’t work very well, but lab sex happens nonetheless. I’ve never seen it, but rumors abound!
It sounds like you want a thermoluminescent material rather than a fluorescent.
CaO makes a bright green-white colour at 1600K and CaCO3 is converted to CaO + CO2 at 2000K – which my Handbook of Chemistry and Physics tells me is temperature of a candle flame (2045K). Perhaps you could bask in your own lime-light…
If you didn’t discard your anthracene candle you could try to dump in some potassium salts (potassium supposedly emits violet light). I’m curious if it will be enough to excite something like anthracene or pyrene.
By the way, pyrene is essentially nontoxic.
K does, and it’s pretty. I used to sprinkle table salt into candles when I was younger and bored…orange is a little boring, though.
Lithium salts would be completely badass.
According to the Aldrich bottle, pyrene will kill fishies and trees, not like you give a shit about them anyway
Wow the dead fish and tree warning? That’s hardc0re.
I always thought that was a mutagenic warning, since the fish is the same size as the tree. It was probably killed by a hardy group of Navy Seals, but not before some of them were taken down and ripped apart by the gigantic fish. Its dead body on the Aldrich label is a warning not to dump the chemical into the water lest a Hollywood-esque story ensues. I’ve often thought about it while handling Aldrich bottles with that label, and imagined myself as the one emptying clips at the scaly beast as it was flying out of the water at me and I was screaming “Why won’t you die, you mutated freak!!??”
But after a few minutes it was always back to my boring and worthless life as a graduate student doing some stupid reaction. Besides, a mutated fish that size wouldn’t be any more maneuverable than a blue whale. And that’s what gives the Navy Seals a chance.
It’s the tree that’s small. It’s all about perspective.
Oh…. I see. Well, I’m pretty embarrassed now.
sigh…was hoping for uncleal to say something
sigh…was hoping uncleal would say something…