Have you ever looked at flames and wondered why they produce different colors as they burn? Color can reveal a lot about the temperature as well as the material that is burning, and these indications can be useful to know. Let’s take a look at common colors and what they represent.
Red
Red flames are generally the coldest, and the deepest reds produce temperatures between 1000 and 1800 degrees Fahrenheit. Flames that are barely visible are on the cooler end of the spectrum whereas ones with a deep-cherry color tend to be the hottest.
Orange
Orange flames are the most common, and they fall into the mid-range of the temperature spectrum. Deep orange flames indicate that a fire is around 2000 degrees Fahrenheit while clear orange indicates that temperatures are around 2200 degrees.
White
The dullest white flames that we see burn at around 2400 degrees, and bright whites develop once temperatures reach 2600 degrees Fahrenheit. Dazzling, sparkling white flames can reach temperatures between 2700 and 3000 degrees.
Blue
Blue flames, such as those produced by natural gas or propane, can reach temperatures in excess of 3000 degrees Celsius, or 5500 degrees Fahrenheit, and they also consume the highest amount of oxygen. However, a blue flame that is narrow and has a pinpoint head, such as what occurs with an oxyacetylene torch, can reach temperatures in excess of 6000 degrees, which is more than hot enough to cut through metal like butter.
Candle Flames
Candle flames tend to be hotter in the center, and temperatures can reach up to 3000 degrees Fahrenheit. However, temperatures quickly cool as you get to the outside of the flame, and red ones burn at around 1500 degrees.
Different Chemicals
Chemicals can also influence the color of a flame that may not be associated with temperatures alone. For example, Lithium Chloride will produce a pinkish-red color. Red flames can be produced by strontium chloride or nitrate. Orange flames can be produced by calcium chloride, and yellow flames can come from barium chloride. Table salt, or sodium chloride, produces a light orange color, and green flames can be produced by copper sulfate and boric acid. Blue flames are produced by butane as well as copper chloride. Finally, you can produce violet flames with a combination of potassium sulfate and potassium nitrate where a peach colored flame is produced by potassium chloride.
Fun With Campfires
If you want to experiment to see how different compounds produce different colors, consider tossing a few into a campfire. This is a fun way to learn more about the chemicals and temperatures associated with flame color, and it’s kind of cool as well. If you don’t have some of these compounds on hand, you can order kits that are specifically designed for campfires.
While you really don’t need to know how colors relate to flames, it can be helpful. For example, you can tell when a forge is hot enough to melt certain types of metals and ores. You can also assess what may be burning in a structure fire as a way to gauge temperature or what possible hazards may exist before going inside to rescue someone. These are a couple of examples that illustrate why it is worthwhile to learn more about flame colors, and doing so can also be fun at the same time. Learn more about flame colors, do some experimentation, and chances are that you can put this knowledge to good use in the future as well.
