How does fuel composition affect the color of a flame?

Fuel composition significantly influences the color of a flame due to the different chemical compounds that are burned. Hydrocarbon fuels, for instance, typically produce a yellow or orange flame due to the presence of soot particles that glow when heated. In contrast, fuels with higher hydrogen content, like natural gas, tend to create a blue flame because they combust more completely, producing fewer soot particles. Additionally, the presence of certain metals in the fuel can result in specific flame colors, such as sodium producing a bright yellow or copper yielding a green flame.