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copper wire vaporization with a candle ? Answered

Hi !

This morning, I was wondering what was the maximum temperature of the flame of a simple candle.
So, this evening, despite the answer is on the internet, I made some quick and various experimentations of my own, mainly because there was nothing interesting at TV ...

I put a wire of tin with a diameter of 1 millimetre over the flame and it liquefied immediately. So I immediately deduced the temperature of the flame was over 505oK ...

Then, I tried with a wire of iron with a diameter of 1 millimetre, and it did not liquefied. So, I deduced the maximum temperature of the candle's flame was below 1811oK.

Then, I tried with a very thin wire of enameled copper (thiner than a hair), the enamel vaporized in a flash and the copper wire quickly liquefied. I deduced the max temp of the flame was over 1357oK.

This gave me a maximal temperature somewhere between 1357oK and 1811oK.

Then, I tried with a thin wire of copper (0.2 millimitres), and it liquefied. But I also noticed that, sometimes, there was a green flame adding to the candle's flame.

On the internet, they say that coppers flame are green.
This would mean that my candle's flame is hot enough to vaporize my copper wire ? and, thus, that the maximal temperature of the candle flame is over 2835oK ?????
If so, why can't it liquefy my 1 millimeters iron wire ?




10 years ago

. Two guesses (I couldn't find anything that gave a definitive answer):
. Temperature is the measure of average molecular motion (kinetic energy). Some of the atoms/molecules will be colder than the average and some will be hotter. You're seeing the hotter ones "boil off"?
. According to the American Chemical Society, the green color is caused by copper(II) chloride.
. According to Wikipedia, copper(II) chloride "decomposes at 993°C (anhydrous)."
. I'm guessing that when the CuCl2 decomposes, the Copper atoms ionize.
. Why would you have CuCl2 in your wire? I dunno. I'm just guessing. :)


10 years ago

be aware that very thin wires will be prone to oxidizing / burning very quickly compared to something more substantial, for example you can get wire wool to burn, and if you blow on it you can get it to drip molten iron, but something like a "burning bar" needs a supply of pure oxygen. So what im basically trying to say is that very thin wires may disappear because you have reacted away all the metal, rather than melting / vaporising it. Try using different parts of the flame to see if you can observe oxidizing vs reducing effects


11 years ago

Wow! I want to try this... *runs away*

What *is* the answer, anyway?


Reply 11 years ago

According to wikipedia, they say the temperature of a candle flame is about 1400oC ...

I'd be curious to know how they measured that. But I'm currently too tired to make further researches (time to sleep) ...


Reply 10 years ago

I recently measured the flame of a methane Bunson burner with a simple thermocouple and found it to be approximately 1000-1200 degrees centigrade. Just a little FYI.


11 years ago

Also remember that with very fine wires, filings, or powders you will be burning them, not necessarily melting them. Fine strands of steel wool will ignite in a candle flame.


11 years ago

Missing information: The width of the wire (and length to some degree) will increase the need for higher temperatures, as there will be more mass being heated, so the heat gets further distributed. If you had used, say, Iron powder, instead of wire, it would flash and sparkle like tiny welding sparks and would be "gone". Metals conduct heat fairly well, so this phenomenon is more noticeable with them then with non-conductive materials.


Reply 11 years ago

Yes, that was one of my conclusion as a wire of copper with a diameter of 1 millimeter will not even liquefy.
If I remember all of that tomorrow (I'm almost sleeping already) and more even if there is nothing a TV again, I will probably try various powders (or tiny bits) just to see if and how they vaporize =o]


Reply 11 years ago

A warning with "true" powders (powders, not just filings): many of them can be "explosive" depending on how they are "introduced" to the flame. I would advise you start small. I have seen Talc (the softest mineral there is) flare in a torch flame when a handful was poured over the flame.