DENJIRO: Today, I’ll show you a mysterious phenomenon using candles. I have here two candles in a transparent box. As you can see, there is a long candle and a short candle. Now, in this beaker, you can’t see it, but there’s carbon dioxide inside. What will happen if I slowly pour carbon dioxide into the box? Let’s find out.
BOY: The short candle went out first!
DENJIRO: Let me explain why this happened. Carbon dioxide is heavier than air. So when I slowly pour it in, it accumulates starting at the bottom. Since the concentration of oxygen decreases starting at the bottom, the short candle goes out first. Let’s try another experiment.
Once again, I have a long candle and a short candle in a box. They are both lit. This time, I’m going to cover the box. In this case, which candle will go out first?
BOY: I’m sure it’ll be the same as before.
DENJIRO: Let’s try.
BOY: The long candle went out first!
DENJIRO: Let me explain why this happened. Since carbon dioxide is heavier than oxygen, you’d think it would accumulate from the bottom. However, if you cover the box, the carbon dioxide produced by the burning candles rises because of heat and accumulates at the top. Furthermore, when a candle burns, an equal amount of water vapor is produced as well, and it accumulates at the top. As proof, you can see that the box is a bit foggy. Due to the carbon dioxide and water vapor produced by the candles, the oxygen concentration decreases from the top. Therefore, the long candle went out first.
I hope energy will bring you all happiness. Our magic word is "Happy Energy!"