When you light the wick of a candle the heat melts the wax and it creeps up the wick. As it meets the flame, wax vapour forms, mixes with oxygen in the air and burns!
The first time you lit your candle you most likely had to touch the wick with the flame of your match. This makes the wick catch fire, which starts the combustion reaction. The wax around the wick starts melting, and it is from this liquid wax that vapor is created inside the flame. The wax vapor starts to burn and creates the stable candle flame that you see. When you blew out the candle you should have seen white smoke rising up into the air from the wick. This is the wax vapor, which becomes visible as it condenses into small liquid droplets in the cooler air.
If you touched the wax vapor (white smoke) with another flame, the candle should have immediately lit up again. This time you didn’t even have to touch the wick or another part of the candle. Lighting the vapor is enough to get the candle burning again. When you placed two or more candles next to each other and blew one out the burning candle’s flame should have reignited the wax vapor of the extinguished one. You might have realized that it is actually quite hard to keep a candle extinguished when it is so close to a burning one. It lights up again due to the fact that the wax vapor of the blown-out candle is touching the remaining candle flame. What you end up seeing is the candle flame jumping from one candle to another!
Credit : Scientific American
Picture Credit : Google
