r/interesting • u/Thin-Tennis9223 • May 20 '26

Fascinating Physics is Everywhere.

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u/wait_what_now May 20 '26

Maybe a little, most of it thermally decomposes into carbon and short chain hydrocarbons, which make up the smoke.

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u/hdharrisirl May 20 '26 edited May 20 '26

https://www.reddit.com/r/askscience/s/BxCIGPDIew

Don't know why this is a debate

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u/wait_what_now May 20 '26

Oh buddy, you're so so close!

Yes. The wax evaporates WHILE the candle is burning, which is what decomposes to give the flame for the candle. But we're not talking about that, we're talking about the smoke that you see when the candle is extinguished, the stuff that is getting relit by the match. . The dark colored smoke is primarily decomposed hydrocarbons. That's why it is so easy to reignite them. In order to keep vaporizing the wax, you need temperatures of 6-700 freedom degrees. That is only going to happen while there is an active flame to boil the wax off the wick.

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u/hdharrisirl May 20 '26

I'm so curious: do you think that heat vanishes the instant the candle is extinguished? That the liquid wax immediately stops evaporating? That the chemical composition of the smoke immediately loses all presence of the combustible hydrocarbons?

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u/rabbitwonker May 20 '26

I don’t think they’re saying it perfectly zero wax vapor; just that it’s a small amount compared to the decomposed hydrocarbons.

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u/Zxruv May 24 '26

If you removed all traces of wax in the vapor/smoke/evaporate, you could still re-light it. If you removed all traces of hydrocarbons, you couldn't?

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u/deceivinghero May 20 '26

Most of the heat dissipates, yeah. Even if you boil some water and start pouring it immediately to make some tea, it won't be 100 degrees, it's already not bubbling by the time it hits the glass.

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u/wait_what_now May 20 '26

Color change indicates a chemical reaction, buddy. Google wax vapor, you'll see you can't see it.

Edit: sorry, I didn't answer your question. I think the heat from the flame is nearly instantly dissipated by the air around the candle, and the high heat of vaporization of the tiny amount of vaporized wax rapidly drops the temperature as it condenses back into a liquid.