Eli5: What happens to all the melted candle over time? Are we just inhaling a whole candle while it burns?


Eli5: What happens to all the melted candle over time? Are we just inhaling a whole candle while it burns?

In: Chemistry

Candle wax is the fuel burned off, any scent added is being inhaled. Any wick left too long burns and releases ash into the air.

The wax reacts with the oxygen in the air to form water, carbon dioxide with a smattering of carbon monoxide and soot.

So some of the carbon dioxide you breathe in will likely have come from the burning candle, but I wouldn’t say that it is a candle anymore.

Pretty much, but the wax decomposes when burning into mostly water, carbon dioxide, some various carbon compounds and some other random compounds. Most of it just dissipates.

The wax is the fuel, the wick is just a ladder for the melted wax to climb up so that it can evaporate from the heat of the flame and burn more easily. The wax that drips down the sides is just wasted fuel, no different than if you spilled gasoline down the side of your car.

The stuff that melts is the stuff that burns. The wick isn’t really the main thing that burns. It just transports melted wax to the flame. The wax then evaporates into fumes, which react with oxygen.

As the wax is make of long chains of carbon with a load of hydrogen stuck on, burning it forms carbon dioxide (CO2) and water vapour (H2O), which goes in to the air.

So yep, we’ll inhale some of the stuff that was the candle, but in a form we inhale anyway!

Yes, kind of. Also, burning a lot of candles inside your home isn’t too good. We once had a neighbor who really liked candles. Once I was looking after her pets when she was on holiday and I noticed a thin layer of black material on the windows and ceiling. I then browsed a bit and there are candles that aren’t that bad for you.

This is perhaps the best explanation I have ever seen. [The Engineer Guy replicated *The Chemical History of a Candle* lectures by Michael Faraday](https://www.youtube.com/watch?v=RrHnLXMTOWM&list=PL0INsTTU1k2UCpOfRuMDR-wlvWkLan1_r)

I think it’s well suited for younger audiences who might also be interested in learning what science is really about… because the lecture really is more about “How to Science” and Faraday just used a candle to convey that.

I actually have the same question about when I lose weight. Where does the fat go and how does it go away?

I like this question! It would be cool to burn a candle on top of a precise digital scale that stays on and record a timelapse, so you could see the candle getting lighter as it burns.

…Should I stop burning candles so much? This thread makes me feel like I’m gonna get lung cancer.