How does a candle work?
Candles really are an amazing lighting system — the fuel itself is the package. There are two parts that work together in a candle: • The fuel, made of some sort of wax • The wick, made of some sort of absorbent twine The wick needs to be naturally absorbent, like a towel, or it needs to have a strong capillary action (as in glass fiber wicks used in oil lamps). If you buy a length of un-waxed wick at a craft store and play with it, you will find that it feels like soft string and absorbs water very well. This absorbency is important in a candle because the wick needs to absorb liquid wax and move it upward while the candle is burning. Paraffin wax is a heavy hydrocarbon that comes from crude oil. When you light a candle, you melt the wax in and near the wick. The wick absorbs the liquid wax and pulls it upward. The heat of the flame vaporizes the wax, and it is the wax vapor that burns. You can prove that it is wax vapor, rather than liquid wax, that is burning with two experiments:
