The principle of operation of the candle uses the phenomenon of self-feeding:
A candle is made of a block of wax or paraffin whose center is traversed by a wick, cotton for example.
When the candle is lit, the heated air melts the wax around it. The melted wax rises along the wick by capillary action as paraffin fluid tends to rise along the wick up close to the flame.
This fluid evaporates then paraffin is then mixed with air and some of its molecules form a combustible gas. It was burned by the flame, allowing the fuel.
For the flame is maintained, it is necessary that the temperature of the burning is sufficient.
The flame is extinguished when you blow hard enough over for the breath causes evacuation of heat from the combustion zone by air convection. In this way, the flame is deprived of heat, one of the three summits of the fire triangle (oxygen, fuel and energy).
Candles: Usage today
Candles: In Medicine