"Blue Flame" refers to a specific type of flame that appears blue due to the complete combustion of fuel. This phenomenon occurs when there is an adequate supply of oxygen, allowing the fuel to burn efficiently. Common examples of blue flames can be seen in gas stoves and certain types of gas heaters, where natural gas or propane is used. The blue color indicates that the combustion process is producing less soot and carbon monoxide, making it a cleaner and more efficient burn compared to yellow or orange flames. This characteristic is important for safety and energy efficiency in appliances like gas furnaces and gas fireplaces.