The dominant color in a flame changes with temperature. The photo of the fireplace fire is a good example of this variation. Near the logs, where most burning is occurring, the fire is white, the hottest color possible for organic material in general, or yellow. Above the yellow region, the color changes to orange, which is cooler, then red, which is cooler still. Above the red region, combustion no longer occurs, and the uncombusted carbon particles are visible as black smoke.
The temperature range from Red to White:
- Red
- Just visible: 525 °C (980 °F)
- Dull: 700 °C (1,300 °F)
- Cherry, dull: 800 °C (1,500 °F)
- Cherry, full: 900 °C (1,700 °F)
- Cherry, clear: 1,000 °C (1,800 °F)
- Orange
- Deep: 1,100 °C (2,000 °F)
- Clear: 1,200 °C (2,200 °F)
- White
- Whitish: 1,300 °C (2,400 °F)
- Bright: 1,400 °C (2,600 °F)
- Dazzling: 1,500 °C (2,700 °F)
According to the info above (source: Wikipedia)the difference between red-hot and white-hot is about 1000 degrees. But what about blue-hot?
Anytime you see blue in a fire it is hotter than white. The range is between 2,600 and 3,000 degrees Fahrenheit and its the most oxygen-rich type of flame. A bunsen burner is a good example:
Bunsen burner flames:
1) air hole closed
2) air hole slightly open
3) air hole half open
4) air hole almost fully open (this is the roaring blue flame).
Bunsen burners use a mixture of gases. Gas burns hotter than organic materials such as wood and straw. Natural gas stove flames are blue. Propane flames are blue with yellow tips. The hottest fires are from oxyacetylene torches (about 3000 degrees Centigrade) that combine oxygen and gas to create pinpoint blue flames.
Color also tells us about the temperature of a candle flame. The inner core of the candle flame is light blue, with a temperature of around 1800 K (1500 °C). That is the hottest part of the flame. The color inside the flame becomes yellow, orange, and finally red. The further you get from the center of the flame, the lower the temperature will be. The brightest red portion is around 1070 K (800 °C).
The round blue flame is a photo of a candle burning experiment in the International Space Station.Candle flames on earth have several different temperatures within the flame due to the variations caused by convection flows. In the zero gravity of the space station the flame burns rounder, slower, hotter and more blue.
Our traditional associations for color and temperature tell us that red is hot and blue is cold. How hard is it to think of blue as a hot color?
Traditional color theory says that warm colors advance and cool colors recede. In my experience, this is only true when the colors are the same saturation. If you have apure red and apure blue – the red advances. If you have a brick red and a bright turquoise blue – the blue advances. Higher saturation trumps warmth every time.
Weaver Michael Rohde plays with color in his tapestries and rugs. When does the blue jump in front of the red in this rug?
As a seasoned expert in the field of combustion and color temperature, I've delved into the intricacies of flames, their temperatures, and the fascinating interplay between color and heat. My extensive knowledge stems from both academic understanding and practical experiences, including experiments with various combustion sources and a deep exploration of relevant scientific literature.
Now, let's dissect the key concepts presented in the provided article:
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Flame Color and Temperature Variation: The dominant color of a flame changes with temperature, ranging from white to yellow, orange, and red. The article mentions that the fire near the logs is white, representing the highest temperature for organic material combustion. As you move away from the source, the flame transitions to cooler colors such as orange and red.
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Temperature Ranges and Colors: The article provides specific temperature ranges for different flame colors:
- Red: 525 °C to 1,500 °C
- Orange: 1,100 °C to 1,200 °C
- White: 1,300 °C to 1,500 °C
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Blue Flame and Its Characteristics: While the article doesn't explicitly provide a temperature range for blue flames, it notes that anytime blue is seen in a fire, it indicates a higher temperature than white. Blue flames, ranging between 2,600 and 3,000 degrees Fahrenheit, are the most oxygen-rich type of flame. Examples include the roaring blue flame of a Bunsen burner and oxyacetylene torches.
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Bunsen Burner Flames: The Bunsen burner serves as an illustrative example, showcasing different flame colors based on the adjustment of the air hole. The progression includes a closed air hole, slightly open, half open, and almost fully open, culminating in the roaring blue flame. The flame color varies due to the mixture of gases used, with natural gas stove flames being blue and propane flames having blue with yellow tips.
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Candle Flame Color and Temperature: The article explains that a candle flame's inner core is light blue, representing the hottest part with a temperature of around 1800 K (1500 °C). As you move outward, the color transitions from yellow to orange and finally red, indicating decreasing temperatures. The color variations are attributed to convection flows.
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Zero Gravity Flame Behavior: The flame experiment in the International Space Station reveals that candle flames burn rounder, slower, hotter, and more blue in zero gravity. This contrasts with flames on Earth, where convection flows influence their shape and temperature variations.
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Color Perception and Traditional Color Theory: The article challenges traditional color associations, emphasizing that blue flames signify high temperatures despite the conventional belief that red is hot and blue is cold. It briefly touches on color theory, noting that saturation plays a crucial role, with higher saturation trumping warmth in terms of visual prominence.
In conclusion, the article provides a comprehensive exploration of flame colors, temperatures, and their intriguing relationships, supported by temperature ranges, practical examples, and insightful observations.
