Which candle will go out first? Why? On Monday I'll post a picture of the same candles taken 10 seconds later.

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ANSWER

We got all kinds of answers with all kinds of good explanations! Here is what actually happens:

The top candle went out very very quickly -- in about 5 seconds. I didn't wait to see how long it took for the lower candle to go out. My first thought was that the lower one would go out first, reasoning that carbon dioxide would sink. But then I remembered that in fire safety class, they teach that in case of a fire you should drop to the floor and crawl out of the building -- the good air is near the floor.

I don't understand what the mechanism is. Now that we know the answer, is it easier to reason our way to a correct explanation?

Thanks to wasoxygen ButterflyEffect reddirecpthoo blackfox026 camarillobrillo b_b AdMan707 cgod francopoli ironpotato mitvit MDZX and mk for playing!

wasoxygen has put up some nice physics quizzes under the tag #quiz, and I've got a couple more nice questions I'll put up soon.