|What state of matter is fire considered to be in?
|Question Date: 2001-05-22|
A flame is in the gas state. It is very hot
Fire is a very rapid chemical
reaction that involves combining a substance with
Even though the reaction releases heat,
it needs some heat to get started.
reaction produces enough heat to keep itself
going. This is why its hard to start a fire, but
once it gets going it will keep going.
candle, the heat will melt the wax and draw it up
the wick, where it is so hot that the wax is
vaporized. The molecules in the flame are in the
gas phase (vaporized wax). These molecules are so
hot that they vibrate and rotate like crazy.
Vibrating and rotating molecules emit light. This
is the bottom blue part of the flame.
half of the flame is often yellow. This is
different than the
blue part. The yellow part
of the flame is air mixed with little particles of
hot soot. Soot is particles of partially burned
The hot soot will glow, just like a
The flame is shaped by
gravity, the movement of the burning gases, and
the movement of air around the flame. What shape
do you think a flame would take in
I think this is a very interesting question,
because fire is still mysterious to people and
they often think that fire is some exotic state of
Fire, or perhaps better "a flame"
is a very hot gas. It is composed primarily of
water vapor, oxygen, nitrogen and carbon
When an organic material (wax, wood,
alcohol) burns, the bonds between carbon and
hydrogen in the material are broken. The released
atoms combine with the oxygen and form carbon
dioxide (CO2 ) and water
(H2O). This is called oxidation and the
reaction gives off heat. The gas can get very hot
(over 1000F). The gas rises and more air (nitrogen
and oxygen) are drawn in at the base of the flame.
The oxygen allows the oxidation to
Some of the energy in this heat
is absorbed by the electrons in the gas. The
electrons then radiate this energy as light, which
is what you see. Very hot gases will radiate blue
light (at the base of a candle). As the gas cools
down the color changes to yellow, then orange,then
red. When the radiation falls into the infra red
you don't see a color anymore but you can feel it
as heat. This radiation now comes from the
vibration of the molecules.
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