Why do candles only smoke when they’re put out?

Question

Why do candles only smoke when they’re put out?

In: Chemistry

Answer 1

A fire is a process that feeds itself. The flame produces heat, which heats up the candle wax under it, which then evaporates into a gas and burns to create the flame.
When you stop the flame, the wax is still hot and still producing gases. But the fire is not there to burn it anymore.