Which color represents the coolest flame temperature?

The color that represents the coolest flame temperature is red. When flames exhibit a red color, it indicates that the combustion process is relatively cooler, typically around 1,000 to 1,500 degrees Fahrenheit. Red flames are often associated with incomplete combustion or lower energy release.

In contrast, blue flames indicate a much hotter combustion, often ranging from around 2,500 to 3,000 degrees Fahrenheit, due to more complete combustion and higher levels of efficiency in the burning process. Green flames result from the presence of certain metal salts being burned, which can occur at varying temperatures depending on the material, and white flames are indicative of very high temperatures, generally above those of blue flames.

Thus, recognizing flame color and its associated temperature ranges is crucial in fields such as fire investigation, where understanding combustion characteristics can aid in determining fire origins and behaviors.