Re: Why do candles weigh more after burning?

Very sorry for the slow response to this. This is an interesting puzzle. After some thought and discussion, most people I've talked it over with agree that it sounds quite impossible on the surface. In theory, the candles should have created carbon dioxide and water, losing mass (primarily carbon) in the process. A visit to The Candle Cauldron suggests precisely this method of measuring the burn rate and calculating the total burn time of a candle. It is possible with a mass-manufactured candle, however, that the candle itself will incorporate air and water (another by-product of combustion) into its chemical structure. In our own lab, we heat titanium metal in various gasses to incorporate the gasses into the metal structure. They can create compounds with as many atoms from the gas atmosphere we put them in as titanium atoms in the metal sample itself. If the candle was manufactured in a large factory and went straight from a large vat of molten wax to a mold through a tube without exposure to air, then it is possible that a large amount of air and water could dissolve in the molten wax of the burning candle. A votive, which you mention using, according to Genwax.com, is a candle designed to be liquid while burning and would be especially susceptible to such an effect. I would strongly suggest several modifications of this experiment. The obvious one is to make your own candles, so that you know the molten wax has already been exposed to air. The next would be to freeze the candles, and burn them cold. That way, most of the wax will not incorporate air. And the other way would be to try different brands of candles and different burning times. Sufficiently long burning times should reduce the overall mass of the candle. This is an interesting phenomenon, and would be a good demonstration if you can repeat it. You should try repeating these anomalous results and share with us all the exact type of candle you used. A normal wax candle could yield very different results. Good luck!