Fire requires three things. Let's look at the
combustion equation, the 'master of
Hydrocarbon (CxHx) + Oxygen (O2)
--heat--> carbon dioxide (CO2) +
Let's examine the equation more closely: The
first item is a hydrocarbon, also known as a
combustible or, as you may commonly hear, a fuel.
In the case of the experiment you noted, this can
be in the form of the body of a match, the wick of
a candle, or the butane in a lighter. Basically,
you need fuel. The second item is oxygen,
which was supplied in the balloon. The third
item is heat, which initiates the reaction by
supplying enough energy to overcome the barrier of
This is the fire equation, and you need
all three of these things for burning.
Firefighters will try to remove one of these
ingredients to stop a runaway fire (Now do you
understand why you have a fire blanket in your
science classroom?). So, the oxygen does not
burn on its own; rather, it needs a fuel. The
more oxygen you have, the more intense the
flame,because you are making the fuel the only
limiting reagent. If the balloon was filled with
air, you would only see a small flame
nd not a' fireball,' because only about 1/5 of
air is oxygen.
This is because oxygen is very flammable and
it bursts into flame very fast, so it keeps
the shape of a ball for a short time.
In the space shuttle, flames are in the shapes
of balls themselves, in the state free fall which
the shuttle in orbit is in, which makes it seem as
if there is no gravity.
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