An interesting thing about a candle is that it is a very good example of the four states of matter. The four states of matter are Solid, Liquid, Gas, and Plasma. Wax, the fuel source of a candle goes through all four of these states of matter. Let's see what happens when we light a candle. We need a catalyst to start the whole thing going, so we touch a flame to the end of the wick. At first the wick itself starts to burn. The flame creeps down the sides of the wick and usually diminishes until it touches the wax. This is when the mechanism starts to work. The heat from the flame melts the wax surrounding the base of the wick directly beneath it. By the principle of capillary action the melted wax is drawn into the wick providing fuel for the flame which bursts to life. The candle continues to burn through an ongoing cycle. Wax in a solid state of matter is melted by the heat of the flame and converts it to a liquid state of matter. The liquid wax is drawn up to the tip of the wick inside the flame. At this stage the liquid wax is heated even more and it vaporizes changing into a gaseous state of matter. The gaseous wax enters the combustion area of the flame and is converted to energy. The energy conversion gives off heat, which melts more of the solid wax. The cycle repeats itself until the wick no longer functions due to consumption or lack of fuel for the flame.