十万个为什么·科学启蒙30篇（3）
10 / 30
正在校验访问权限...
Why Is Flame Usually Orange?
火焰为什么通常是橙色的
-
An orange flame appears when tiny hot particles of carbon—called soot—glow in the heat like tiny lightbulbs.
-
This type of incandescence happens in incomplete combustion, where fuel doesn’t burn fully due to limited oxygen.
-
Candles, wood fires, and gas stoves on low settings all produce such warm-colored flames.
-
Blue flames, in contrast, come from complete combustion and emit light mostly from excited gas molecules.
-
The temperature of an orange flame ranges from about 1,000°C to 1,200°C—hot, but cooler than blue ones.
-
Sodium in salt or food splatters adds a stronger yellow-orange hue because sodium atoms glow brightly at that wavelength.
-
A candle’s wick draws melted wax upward, where capillary action feeds vaporized fuel into the flame zone.
-
If you restrict airflow to a Bunsen burner, its blue flame turns orange and flickers more wildly.
-
Firefighters watch flame color carefully: orange suggests smoldering materials, while blue hints at gas leaks.
-
Even the Sun’s visible surface glows orange-yellow—not from soot, but because its 5,500°C surface emits peak light in that range.