Tesla coil and candles. Footage of a Tesla coil with a candle mounted on its discharge point. When switched on, high-voltage electrical sparks are produced with the purple glow caused by ionisation of air molecules to form a plasma. The sparks produced by the Tesla coil cause the candle flame to flicker and flare up. The candle flame stops flickering and flaring when the power is turned off. This experiment is then repeated with the discharge point inside a candle. This causes the candle to rapidly burn from the inside out and collapse. The destructive electrical discharge becomes visible again at the end of the clip.