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I have seen a candle and gave (diya) burning.

But how exactly they work. Because in candle we use wax but we also use a thread like structure to burn it, although if we try to burn simple wax by Applying heat it will not give flames like in candle it does, simply it will melt! So why thread needed in candle to produce flames , and simply wax cannt produce flames without thread on Applying heat? How exactly combustion with flames taking place in candle?not simply wax?

Same with Gaves, (diya) that we use a cotton dipped in oil to burn it, although if we simply apply heat only to oil it will not produce flames like in diya or gave it does? So why that cotton needed there? How exactly combustion with flames taking place in gave? Not simply in oil?

Suresh Chandra Pal
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2 Answers2

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The wax in candles have a high hydrocarbon content.

When you light a candle, the flame causes the wax to melt close to the wick and this liquid wax gets drawn into the wick due to capillary action. The flame also causes the liquid wax at the bottom of the wick to vaporize so that you now have a mixture of hydrogen and carbon that all react with the air thus creating heat and light.

I'd say the oil used in Diyas are also high in hydrocarbon content, except in Diyas you have a liquid oil as oppose to candles made of wax.

joseph h
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Hydrocarbon vapor is what burns. To sustain a flame, the fuel must be at its vaporization temperature and there must be a continuous supply of it.

The wick has a high surface area, a high heat capacity, and a good structure for capillary action. Thus the liqufied wax near the tip of the wick vaporizes, removing heat from the wick and keeping it from being destroyed by the flame; the wax vapor reacts with oxygen to make more heat and keep the wick from cooling off too much to keep vaporizing the wax; and the liquid wax melted by the radiant heat from the flame is drawn up into the wick by capillary action, allowing the process to continue.

Without a wick, wax and similar substances (oil, fat, kerosene, etc) can still burn, but only once a large quantity of fuel approaches its vaporization temperature. Such fires therefore require significant energy to start, but once they get going they are violent and can only be put out by cutting off the supply of oxygen.

g s
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