What’s in a flame?
The chemistry and physics of fire are surprisingly complicated for something so ubiquitous, but there’s a pretty easy answer for “what’s in a flame?”
When a candle flame is placed between two contacts holding a about ten thousand volts, the flame is pulled to the positive and negative side like a flickering butterfly. The air, usually a good insulator, pulls the ions within the flame to either side, allowing an arc to form.
Check out the full video from Veritasium. Spark more interest with this winning video from The Flame Challenge, explaining what fire is in simple terms.