What is the science behind the burning life of candle

[sonalinm]

Hello,
I am helping my sons to do project about candle. He tested burning life of cool{refrigerated candle} and one at room temperature. Freeze candle burns longer than the other. But when he ask the question, why it happens? hmmm I can say may be because of difference between melting and Freezing points of the wax but I am not sure. Can any expert will explain me what science is behind this project ?

[Amber_MIT]

Hi sonalinm, I'm going to transfer your question to the physical science section. I think those experts will be able to better answer your question.

However, your result makes sense to me. It takes more energy to turn the wax from the freezer into a liquid, so it should take longer to burn. It takes time and energy to get the cold wax to room temperature. The other candle is already at room temperature so it has a head start. This is the expected result assuming all other variables are kept constant. Since the flame itself is so hot though (especially compared to the difference between a cold candle and room temperature), I would think the amount of extra time would be tiny (again, this assumes a perfect experiment in which everything is kept constant). There are probably other factors that lengthen the time, which I'll leave to the physical scientists.

The next question your sons should ask is whether the difference in burn times is large enough that it makes sense for people to take up valuable freezer space with candles .

Another thing you could try to measure (though this might be impossible with eyes and a measuring stick, you'd need to figure out a good measuring system), is the flame itself. Is the flame on the cold candle as bright/large as the room-temperature one (assuming they are the same exact type of candle and the wicks started at the same length)? Since some of energy is being used to warm the candle, I'd think there would be less output of light. If this is the case, frozen candles might last longer, but if they don't burn as bright, are they really better? The difference may be so slight that you may not be able to see it.

[edneu3]

The information Amber provided is right on. To help you better understand the science that is involved in burning a candle, I suggest you look at these web sites. They should help you and your son understand quite a lot.

http://home.howstuffworks.com/question267.htm

http://www.explainthatstuff.com/candles.html

And here's a good description about how to properly control a candle experiment. One thing of importance in your son's experiment is to make sure not only that the candles are identical, but that the wicks are trimmed to the same length.

http://www.candlescience.com/learning/h ... n-test.php

Good luck, and have fun.

[Craig_Bridge]

Another measuremenst/observation you might want to look at are the change in mass (weight) of the candles as they burn in an attempt to understand possible things that affect your result.

When liquid wax runs down the side of a candle, the wick will be exposed faster and burn faster; however, the wax that runs down the side and resolidifies is NOT burned.

[sonalinm]

Thanks you Amber, ednu and Craig for quick reply.

Amber, you are right..it was only 30 sec difference..I don't think this idea is useful to save money and use freezer space So may be he will prove his hypothesis wrong.

[NanoNanoPudding]

Hmm, what is the science behind a burning life of a candle? I think it may be because of the certain wax length or something... Sorry, i'm not too good with candle stuff, I just like lighting them! (Laugh)

I hope your son did well on his hypothesis or whatever it is! haha!