When a candle smokes, it is the unburned wax vapor that is not combusting properly, not the wick itself. This smoke is actually made of tiny wax droplets, carbon bits, and gases, like an invisible fuel cloud waiting to ignite.
And here’s the fun part: it will ignite.
If you blow out a candle and quickly hold a match to the smoky trail, the flame jumps down the smoke and relights the candle! It’s a little magic trick powered by science.
That’s because candles burn in two steps:
First, the heat of the wick melts and vaporizes the wax.
Then, that wax vapor catches fire and keeps the flame going. If the vapor doesn’t burn fully, it becomes smoke—which can still ignite if it finds enough heat.
Here’s another fun candle fact. NASA has studied candle flames in space. Without gravity, flames form perfect spheres, and combustion behaves totally differently.
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