How does a fire give off light?

A fire emits light due to the combustion process, where heat causes the molecules in the burning material to become excited and release energy. As these excited molecules return to their normal state, they emit energy in the form of light, primarily in the visible spectrum. Additionally, the heat from the fire causes incandescence in solid particles, such as soot, contributing to the brightness. The combination of these processes results in the characteristic glow of flames.