The secret of the candle lies in the wick. A matchstick ignites the wick. The heat of the flame melts the wax of the candle. The liquid wax rises up in the wick, and more it evaporates, more higher it rises. The vapour burns. Wax is made up of carbon and hydrogen. Both elements react with oxygen during burning, whereby water vapour, soot, and waste gases like carbon monoxide and carbon dioxide are produced. This also gives the colours to the candle flame – yellow light from carbon and the blue light from water vapours.