Sciencemadness Discussion Board

Smoking Fingers

Teen Chemist - 28-4-2012 at 15:05

I found this video on Youtube
http://www.youtube.com/watch?v=rEw2ugyya_M&feature=relat...
and I wanted to know if any of you know what the yellow substance.

weiming1998 - 28-4-2012 at 17:09

Definitely white phosphorus. The combustion of red phosphorus (on the match striker) partially gives white phosphorus which melts and condenses on the cold sink. White phosphorus has an autoignition temperature of 38 degrees celsius and burns to give phosphorus pentoxide, which sublimes and condenses to give that white smoke. Rubbing your fingers together creates friction, and friction increases the temperature on your fingers to above the autoignition point of white phosphorus, thus it combusts in your fingers and gives that smoke effect.

White phosphorus is not carcinogenic, and the person with the top comments said on Youtube, but it can be absorbed through the skin and even a few hundred milligrams can causes bone damage, and the place where the phosphorous is in contact with might have to be amputated. So if you want to try that trick, at least have some sort of protection.

barley81 - 28-4-2012 at 19:43

No, it is not above the autoignition temperature. Phosphorus is known to smoke and glow in air at room temperature. I wouldn't recommend getting white phosphorus on yourself. Just look up "phossy jaw." It's a terrible disease.

Teen Chemist - 29-4-2012 at 05:28

Thanks and I do know what phossy jaw is.

Variscite - 9-6-2013 at 14:45

White phosphorous on the skin, sounds perfectly fun and healthy!:P
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(If you cant tell, im joking.)

[Edited on 6-9-2013 by Variscite]

a_bab - 9-6-2013 at 21:14

Phossy jaw means heavy exposure for many years. "Hundreds of mg" is pure crap - 100 mg will kill you long before you get phossy jaw.

As a kid I did this trick many times, but the smell of the "oil" left with the P content is really disgusting after a while. I once got enough from a particulary thinker striker to have it ignited on my fingers: a small painfull blister was all I got.

I personally think that occasionaly playing whith WP won't get you any trouble, but doing it so daily will get you after a while (years).


I recomend this sordid tale as a lecture for a better understanding of P effects in humans.

woelen - 9-6-2013 at 23:21

This 'smoking fingers' thing is not a severe risk. The amount of phosphorus involved is very low (in the order of magnitude of a milligram) and as already mentioned, if this thing is repeated a few times then there is no risk at all.

Toxicity of chemicals frequently is strongly exaggerated. You don't get sick of a few times exposure to a few micrograms of phosphorus (that is what you may get into your body, probably even less). Frequenty, people confure the amount they are working with with the amount they get into their body. If a document says that 100 mg of a certain compound is the LD50 dose, then releasing 100 mg into e.g. the air does not mean that you have a 50% chance of dying from that. How much of that 100 mg will enter your body?

With this I do not want to say that there are no risks or only low risks. You have to be careful! But you should not exaggerate things and should not fear things. Respect for the chemicals and a clear mind when working with them is important.

Fantasma4500 - 10-6-2013 at 05:32

oh yes perhaps one of my favorite ''tricks''
i prefer to do this with scraping off the ''striker powder'' isntead and ignite it.. the pile you should be able to carry around and just rub your fingers over
apart from that no matter what you guys say, my opinion on the smell of freshly burnt phosphorus is the most brilliant smell i have ever come by yet and probably it wont ever be topped