When we burn a candle, the melting of solid wax is a physical change as melting involves just change in state and no new substance is formed. Whereas, burning of wick of the candle is a chemical change. The wick absorbs some molten wax. The molten wax vaporizes due to the heat produced by the flame. The wax vapour near the flame burns to give new chemical substances. Hence, it is a chemical change.