A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat, or be used as a method of keeping time. The candle can be used during the event of a power outage to provide light.
For a candle to burn, a heat source is used to light the candle's wick, which melts and vaporizes a small amount of fuel. Once vaporized, the fuel combines with oxygen in the atmosphere to ignite and form a constant flame. This flame 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 liquefied fuel then moves upward through the wick via capillary action; the liquefied fuel finally vaporizes to burn within the candle's flame.