What you Need
What to do
Light the candle and wait until it is burning well and has a glowing ember at the end, it works better when the wick is too long.
Carefully pour the excess wax out of the candle.
Blow the candle out gently.
Quickly wave the lit lighter near to but not next to the candle. It works best if you wave it in the smoke.
What may happen
With any luck the candle should relight without being touched by the flame
Why does it happen?
It is very difficult to set light to a lump of solid or even liquid wax because the surface area is very low so it can't react with oxygen very fast however it just takes a match to light a candle.
A candle works by melting the wax which is then drawn up the string like wick by capillary action. The wick is heated by the flame and has a large surface area so the wax vapourises. Now the wax has a huge surface area because it is a gas and it has enough energy to start reacting with the oxgyen in the air to burn.
When you blow out the candle the wick is still hot so the wax continues to evaporate for a few seconds. Eventually this wax condenses into a cloud of tiny wax particles we call smoke.
If you bring another flame to the vapour it can still burn so it will relight the candle.
This is why petrol is much more dangerous than diesel even though it will catch fire at a lower temperature. Petrol has a much lower boiling point and so will vapourise much more easily, this means there is much more vapour to light if there is a spark.