Why does a candle make no smoke when it is lit but makes a lot of smoke when you blow it out?
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It’s not smoke. It’s wax vapor.
Solid wax can’t burn.
Liquid wax looks like it can burn, but in fact, it can’t. Only wax vapor can burn (mixing with the oxygen of the air).
When you put a flame on the wick, it melts the wax in the wick, but it vaporises some too. That vapor instantly catches fire (because the flame of the lighter is there).
The heat from the burning wax vapor melts some more of it, vaporises some more of it, which burns because there’s a flame, and it’s a cycle.
You interrupt the cycle by blowing the flame away.
The wax is still hot enough to evaporate a bit, but that vapor doesn’t have a flame to light it, so it just slowly rises in the air, looking like smoke.
A few seconds later, the liquid wax isn’t hot enough to evaporate anymore. No more “smoke”.
If this were true, then putting a flame in the “smoke” would make it catch fire, proving it’s not smoke. You can do that experiment.
1. Light a candle
2. Light a lighter, put its flame above the candle
3. Blow the candle out (without blowing the lighter out)
4. As soon as you see smoke, make it run through the lighter.
This should make the smoke disappear. In some cases, the fire will run back from the lighter, along the smoke-path to the wick, and relight the candle. Cool shit.
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