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Why is the color of a flame usually orange?
The typical,
bright, yellowish-orange upper part of a flame is due to the heating of
unburned carbon particles.
The
temperature of the fire and the material being burned are the factors that
determine the color of the flame. The various colors of flames in a wood fire
are due to the different substances in the flames.
The strong
orange color of most wood flames results when sodium contained in the wood is
heated
The
temperature of wood flames is lower than that of candle flames, which colors
the wood flames orange, not yellow. If, however, some of the carbon particles
in the fire are very hot, the color will be yellow. The product of the burnt
carbon, when it has cooled, is black soot.
Since fire
needs oxygen to burn, and since the bottom of a candle flame does not get much
oxygen, it is the hottest spot in the flame and is blue in color.
The flame
cools and changes color as it moves away from the source of the flame, because
it is exposed to more oxygen. The temperature change causes the color of the
flame to change from blue, at the hottest, lower portion of the flame, to the
typical, bright, yellowish-orange or bright orange color with which most people
are familiar. Which shade of orange is seen at the upper portion of the flame,
where the flame is the coolest, depends upon the material being
burned.
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Electrical, flammable liquids, ordinary combustibles, and metal comprise the
four types of fire.
- In a year,
lightning will cause 10,000 fires in the United States alone.
- More than
5 percent of the land on Earth is burned by fire every year.
- The bark
of the redwood tree is fireproof. Fires in redwood forests take place inside
the trees.
- A
perfectly clean fire produces almost no smoke. Smoke simply means that a fire
is not burning properly and that bits of unburned material are
escaping.
- At 12,000
feet above sea level, there is barely enough oxygen in La Paz, Bolivia to
support combustion. The city is nearly fireproof.
- Forest
fires move faster uphill than downhill.
- Of all
the world's peoples, the only ones known not to use fire are the Andaman
Islanders and the Pygmies.
- The word
"curfew" is derived from an old French word that means," cover fire." In Europe
during the Middle Ages, a curfew was a metal cone or shield that was used to
put out the hearth fire in the evening. The word "curfew" came to mean the end
of the day's activities.
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