Candle
A candle is a light source usually consisting of an internal wick which rises through the center of a column of solid fuel. Prior to the mid 19th century, the majority of candles were tallow (a byproduct of beef fat rendering). The fuel now is nearly always some form of wax, with paraffin wax being the most common. Soy and vegetable-based candles are also available, however.
Prior to the candle being ignited, the wick is saturated with the fuel in its solid form. The heat of the match or other flame being used to light the candle first melts and then vaporizes a small amount of the fuel. Once vaporized, the fuel combines with oxygen in the atmosphere to form a flame. This flame then provides sufficient heat to keep the candle burning via a self-sustaining chain of events: the heat of the flame melts the top of the mass of solid fuel, the liquified fuel then moves upward through the wick via capillary action, and the liquified fuel is then vaporized to burn within the candle's flame.
The burning of the fuel takes place in several distinct regions (as evidenced by the various colors that can be seen within the candle's flame). Within the bluer, hotter regions, hydrogen is being separated from the fuel and burned to form water vapor. The brighter, yellower part of the flame is the remaining carbon soot being oxidized to form carbon dioxide.
(courtesy wikipedia.com)
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