DarkRange55
Enlightened
- Oct 15, 2023
- 1,790
Fire is visible primarily due to blackbody radiation, which occurs when an object emits electromagnetic radiation due to its temperature. When a substance combusts, it heats up and emits light across a range of wavelengths. The color of the flame depends on the temperature of the fire and the chemical composition of the burning material.
As the temperature of the fire increases, it emits light across a wider spectrum of wavelengths, making it more visible to the human eye. The visible light emitted by the fire is what we perceive as the flame's color
In a typical fire, both soot particles and the hot gases in the flame contribute to the overall emission of light. The visible light emitted by the flame is a combination of emissions from both the incandescent soot particles and the hot gases undergoing combustion
Hotter flames have predominantly shorter wavelengths which correspond to higher energy levels. So they progress through red, orange, yellow, blue, violet, and ultraviolet. That last one will burn your retinas, which is why you don't look at arc-welding flames. Or the sun. Or nuclear explosions.
Rarely do we see the deep violet colors in the hottest flames, because our vision is not sensitive to these wavelengths.
Blue flames usually indicate higher temperatures because they result from complete combustion, where all the fuel is efficiently burned, producing a clean, blue flame. The high temperature of blue flames is due to the intense heat generated by the complete combustion process.
Violet flames, on the other hand, are less common and often result from the presence of specific elements or compounds in the flame that emit light at shorter wavelengths. While violet flames may indeed be hot, they are generally not as hot as blue flames, which are characteristic of the highest temperatures achievable in a typical combustion process.
Ultraviolet (UV) radiation emitted by extremely hot flames, such as those in arc welding, can indeed be harmful to the eyes. Prolonged exposure to UV radiation can cause damage to the cornea and retina, leading to conditions like photokeratitis (similar to sunburn of the eye) or even long-term damage such as cataracts or macular degeneration.
The hottest color of flame is typically blue or white. Blue flames are often associated with the highest temperatures because they result from complete combustion, where all the fuel is efficiently burned, producing a clean, blue flame. White flames can also indicate very high temperatures and often result from a mix of different chemical reactions and elements undergoing combustion. In general, the hotter the flame, the closer its color tends to be to blue or white.
In addition to blackbody radiation, the presence of excited molecules and radicals in a flame can also contribute to its color. When the fuel undergoes combustion, it can form intermediate molecules such as CH (methyl radical) and CH2 (methylene radical). These molecules can become excited by the heat of the flame and emit light as they return to their ground state.
The emission of light from these excited molecules contributes to the blue color often seen in flames. This phenomenon is known as molecular emission or molecular band emission. The specific colors emitted depend on the molecular species present in the flame and their energy levels.
A pure hydrogen flame, lacking carbon, does not produce soot or the hydrocarbon radicals CH and CH2. As a result, such a flame is usually invisible to the naked eye.
When a flame exhibits a red or orange color, it indicates incomplete combustion, typically due to a lack of sufficient oxygen supply to the fuel. In such cases, soot particles may be produced as a result of incomplete combustion, and the flame may emit carbon monoxide (CO) and other incomplete combustion products. Incomplete combustion can occur for various reasons, including problems with the fuel source (such as impurities or poor quality fuel) or issues with the fuel-air mixture process (such as inadequate mixing or improper fuel jet formation).
A "white" colored flame is typically a blend of multiple colors rather than simply being the top-end of a yellow flame. Flames emit light due to the incandescence of burning particles and the chemical reactions occurring within the flame.
In a typical flame, such as that from a candle or a gas stove, the yellow color comes from the incandescence of soot particles and carbon compounds in the flame. However, a white flame may contain additional colors due to the presence of other compounds or elements undergoing combustion.
For example, a white flame can result from the combustion of certain metal ions or salts, which emit light of various colors when heated. The combination of these different colored emissions can give the flame an overall white appearance. Additionally, a white flame may also contain some yellowish components, especially towards the lower end of the flame where incomplete combustion occurs.
So, while a white flame may include some elements of yellowish color, it is typically a blend of multiple colors emitted by various substances undergoing combustion.
As for temperatures approaching 50 million degrees, at such extreme temperatures, the emission spectrum of the flame would extend into the higher energy range, including ultraviolet and potentially even X-rays or gamma rays. These high-energy emissions would not be visible to the human eye as visible light but would instead consist of electromagnetic radiation at wavelengths beyond the visible spectrum.
When copper-containing materials burn, such as copper chloride or copper sulfate, they can produce a green flame.
The green color of the flame is due to the emission of light by excited atoms or ions of copper. As these atoms or ions return to their ground state from an excited state, they release energy in the form of light, with a characteristic green color.
Other elements or compounds can also produce green flames under specific conditions. For example, boron compounds can sometimes produce green flames, as can certain barium compounds.
The dancing of a flame is influenced by various factors including the heat of the flame, the movement of surrounding air, and the shape of nearby objects. Hot gas rises when there is gravity, and this draws more air into the flame -
As hot gas rises due to buoyancy, it draws in surrounding air, which can cause fluctuations in the flame's shape and movement. Disturbances in the airflow caused by wind, the shape of objects near the flame, etc. cause the flame to move unpredictably.
Fire is not a form of plasma in the strict sense of the term. While fire does involve the ionization of gases and the release of free electrons, it typically lacks the characteristics that define plasma, such as collective behavior of charged particles and the presence of distinct plasma properties like magnetic confinement.
Fire is instead a visible manifestation of the combustion process, which involves rapid oxidation reactions between a fuel and an oxidizing agent (typically oxygen in the air). In a flame, hot gases rise due to buoyancy, drawing in surrounding air and sustaining the combustion process. While the flame does contain ions and free electrons, it does not exhibit the coherent behavior or unique properties associated with plasma.
However, certain types of flames, such as those produced by electrical discharges or in specialized combustion systems, can exhibit plasma-like behavior under specific conditions. These cases may involve the presence of more pronounced ionization and collective behavior of charged particles, resembling characteristics of plasma.
Fire "it's not a state of matter", or even "it's a process". That description is that waterfalls and fire are emergent phenomena. Basically, the process is "combustion", the emergent phenomenon is "fire". Similarly, the process is "a cascade of multiphase droplet breakup due to surface tension and significant differences in density in a gravitational field", the emergent phenomenon is "a waterfall". Also, while both waterfalls and fire are made of constituents, a useful description of them requires understanding their combined emergent behavior, not their constituent behavior nor their root cause processes.
As the temperature of the fire increases, it emits light across a wider spectrum of wavelengths, making it more visible to the human eye. The visible light emitted by the fire is what we perceive as the flame's color
In a typical fire, both soot particles and the hot gases in the flame contribute to the overall emission of light. The visible light emitted by the flame is a combination of emissions from both the incandescent soot particles and the hot gases undergoing combustion
Hotter flames have predominantly shorter wavelengths which correspond to higher energy levels. So they progress through red, orange, yellow, blue, violet, and ultraviolet. That last one will burn your retinas, which is why you don't look at arc-welding flames. Or the sun. Or nuclear explosions.
Rarely do we see the deep violet colors in the hottest flames, because our vision is not sensitive to these wavelengths.
Blue flames usually indicate higher temperatures because they result from complete combustion, where all the fuel is efficiently burned, producing a clean, blue flame. The high temperature of blue flames is due to the intense heat generated by the complete combustion process.
Violet flames, on the other hand, are less common and often result from the presence of specific elements or compounds in the flame that emit light at shorter wavelengths. While violet flames may indeed be hot, they are generally not as hot as blue flames, which are characteristic of the highest temperatures achievable in a typical combustion process.
Ultraviolet (UV) radiation emitted by extremely hot flames, such as those in arc welding, can indeed be harmful to the eyes. Prolonged exposure to UV radiation can cause damage to the cornea and retina, leading to conditions like photokeratitis (similar to sunburn of the eye) or even long-term damage such as cataracts or macular degeneration.
The hottest color of flame is typically blue or white. Blue flames are often associated with the highest temperatures because they result from complete combustion, where all the fuel is efficiently burned, producing a clean, blue flame. White flames can also indicate very high temperatures and often result from a mix of different chemical reactions and elements undergoing combustion. In general, the hotter the flame, the closer its color tends to be to blue or white.
In addition to blackbody radiation, the presence of excited molecules and radicals in a flame can also contribute to its color. When the fuel undergoes combustion, it can form intermediate molecules such as CH (methyl radical) and CH2 (methylene radical). These molecules can become excited by the heat of the flame and emit light as they return to their ground state.
The emission of light from these excited molecules contributes to the blue color often seen in flames. This phenomenon is known as molecular emission or molecular band emission. The specific colors emitted depend on the molecular species present in the flame and their energy levels.
A pure hydrogen flame, lacking carbon, does not produce soot or the hydrocarbon radicals CH and CH2. As a result, such a flame is usually invisible to the naked eye.
When a flame exhibits a red or orange color, it indicates incomplete combustion, typically due to a lack of sufficient oxygen supply to the fuel. In such cases, soot particles may be produced as a result of incomplete combustion, and the flame may emit carbon monoxide (CO) and other incomplete combustion products. Incomplete combustion can occur for various reasons, including problems with the fuel source (such as impurities or poor quality fuel) or issues with the fuel-air mixture process (such as inadequate mixing or improper fuel jet formation).
A "white" colored flame is typically a blend of multiple colors rather than simply being the top-end of a yellow flame. Flames emit light due to the incandescence of burning particles and the chemical reactions occurring within the flame.
In a typical flame, such as that from a candle or a gas stove, the yellow color comes from the incandescence of soot particles and carbon compounds in the flame. However, a white flame may contain additional colors due to the presence of other compounds or elements undergoing combustion.
For example, a white flame can result from the combustion of certain metal ions or salts, which emit light of various colors when heated. The combination of these different colored emissions can give the flame an overall white appearance. Additionally, a white flame may also contain some yellowish components, especially towards the lower end of the flame where incomplete combustion occurs.
So, while a white flame may include some elements of yellowish color, it is typically a blend of multiple colors emitted by various substances undergoing combustion.
As for temperatures approaching 50 million degrees, at such extreme temperatures, the emission spectrum of the flame would extend into the higher energy range, including ultraviolet and potentially even X-rays or gamma rays. These high-energy emissions would not be visible to the human eye as visible light but would instead consist of electromagnetic radiation at wavelengths beyond the visible spectrum.
When copper-containing materials burn, such as copper chloride or copper sulfate, they can produce a green flame.
The green color of the flame is due to the emission of light by excited atoms or ions of copper. As these atoms or ions return to their ground state from an excited state, they release energy in the form of light, with a characteristic green color.
Other elements or compounds can also produce green flames under specific conditions. For example, boron compounds can sometimes produce green flames, as can certain barium compounds.
The dancing of a flame is influenced by various factors including the heat of the flame, the movement of surrounding air, and the shape of nearby objects. Hot gas rises when there is gravity, and this draws more air into the flame -
As hot gas rises due to buoyancy, it draws in surrounding air, which can cause fluctuations in the flame's shape and movement. Disturbances in the airflow caused by wind, the shape of objects near the flame, etc. cause the flame to move unpredictably.
Fire is not a form of plasma in the strict sense of the term. While fire does involve the ionization of gases and the release of free electrons, it typically lacks the characteristics that define plasma, such as collective behavior of charged particles and the presence of distinct plasma properties like magnetic confinement.
Fire is instead a visible manifestation of the combustion process, which involves rapid oxidation reactions between a fuel and an oxidizing agent (typically oxygen in the air). In a flame, hot gases rise due to buoyancy, drawing in surrounding air and sustaining the combustion process. While the flame does contain ions and free electrons, it does not exhibit the coherent behavior or unique properties associated with plasma.
However, certain types of flames, such as those produced by electrical discharges or in specialized combustion systems, can exhibit plasma-like behavior under specific conditions. These cases may involve the presence of more pronounced ionization and collective behavior of charged particles, resembling characteristics of plasma.
Fire "it's not a state of matter", or even "it's a process". That description is that waterfalls and fire are emergent phenomena. Basically, the process is "combustion", the emergent phenomenon is "fire". Similarly, the process is "a cascade of multiphase droplet breakup due to surface tension and significant differences in density in a gravitational field", the emergent phenomenon is "a waterfall". Also, while both waterfalls and fire are made of constituents, a useful description of them requires understanding their combined emergent behavior, not their constituent behavior nor their root cause processes.
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