The smoke that catches fire

You blow out a birthday candle. A thin ribbon of smoke curls up. Quick — you hold a lit match an inch above the wick. What happens next?

1Two things to know first

A candle doesn't burn the way you think

You need two small ideas. Watch each one happen:

The flame burns vapor

The flame's heat melts the wax, then turns it into an invisible gas. The flame is really burning that wax-gas floating off the wick — not the solid wax itself.

Smoke is leftover fuel

Blow it out and the wick is still hot. It keeps making wax-gas — but with no flame to burn it, that gas just drifts up as the smoke you can see.

2It depends how fast you are

Same smoke — two very different moments

Match right away ⚡

The smoke is thick and the trail still connects to the hot wick. There's a full ribbon of fuel from the match all the way down. Hold onto that…

Wait a few seconds 🌫️

The smoke spreads out and thins into the air. The fuel gets too spread out to carry a flame — the wick goes cold and quiet.

3Watch the smoke spread

Thick fuel, then thin air

This is the smoke rising off a just-blown-out wick. Slide time forward and watch the thick ribbon of wax-gas spread out and fade into the room.

Seconds since you blew it out: just now
JUST BLOWN OUTA FEW SECONDS LATER

Right away the smoke is a thick, connected ribbon of fuel. Wait, and it spreads thin until there's barely any fuel left in one place.

4Now bring in the match

Hold a lit match in the smoke 🔥

The wick is out. A ribbon of smoke curls up. You bring a lit match into the smoke, an inch above the wick. Guess what happens before you light it.

Guess before you light the match

You blow out the candle and quickly hold a lit match in the curling smoke, an inch above the wick. What happens?