|Do candles burn longer when they are in hot or
|Question Date: 2018-01-18|
A candle works because of the burning of wax,
with the supply of oxygen from the air. Set
fire to the wick, which is the start of the
burning process of a candle. The heat from the
fire will melt and vaporize the wax below. The
vaporized wax will be the adding fuel to the fire
and make sure the candle keep burning, until the
wax is running out (of course, we need air all the
So will the candle burn longer in hotter
air? Cold and hot is a relative
concept. Hot as sun will immediately burn the
whole candle in seconds; while in the coldest
places you may even have trouble setting the fire
to the wick, let alone the burning of the candle.
From those two extremes, you can immediately see
that hotter air will probably make the candle burn
shorter. But this is not exactly what you are
asking. Let's compare the hot air (say 80 degrees
Fahrenheit) in the summer and cold air ( say 40
degrees Fahrenheit) in the winter. Will they
make some differences? The hotter air will
speed up a few processes that will make the
burning faster. For example, the supply of oxygen,
and the heat conduction necessary to melt and
vaporize the wax. But there is one crucial thing
to remember, the temperature of the flames are
much higher than the air temperatures. The
brightest part of the flame has a temperature of
about 2200 degrees Fahrenheit (the top of the
flame), and the hottest part of the flame is about
2500 degrees Fahrenheit (the blue or white edge
of the flame in the very bottom, and this part
plays the major role of melting and vaporizing the
wax). In this sense, the hot or cold air will not
matter that much, because the heat from the bottom
flame is the dominating factor that determines the
burning time of the candle. So to summarize,
whether in hot air or cold air, the candle will
burn probably the same amount of the time.
Although, the hotter air will in principle
make the burning process faster, but it doesn't
play a dominating role. The difference is
minimum (unless otherwise under extreme
Candles work by burning wax. The solid wax
that makes up the body of the candle is melted
by the heat of the flame, then is absorbed
into the wick where it is burned. If the air (and
therefore the solid candle wax) is cold, then more
of the energy from burning must go toward heating
the solid wax before it is melted. This means less
of the candle will melt for a given unit of energy
and the candle will burn more slowly. That being
said, the flame is at a much higher temperature
than the air is likely to be, so the effect
will not be dramatic.
That's a fun question. What do you think? I
think candles would burn a tiny bit longer in cold
air, because there'd be a tiny bit less heat
around the candle and the flame.
Candles in windy or still air is another fun
thing to picture in your mind.
Thanks for the great question!
When you light a candle, you heat up the wax
that surrounds the wick, or the string that runs
through the candle. When the wax gets hot enough,
the wick catches fire. As the wick burns, it heats
the wax under it and that keeps the wick lit.
Should the candle be cold, let’s say because
the air is cold, it will take a little longer to
heat up the wax to get the wick burning. So
candles do burn longer when cold, and candles
are colder when in cold air.
However, the air temperature may not change the
temperature of the wax all that much. Some people
will even put their candles in the fridge to get
the wax even colder, and to get the flame burning
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