Incandescent light appears yellowish compared to fluorescent light. This is because incandescent lamps produce light from heat. The filament in an incandescent lamp is what heats up. Filaments are made out of double coils of tungsten, a type of metal. Tungsten has a high electrical resistance, causing it to glow (incandesce) when an electric current flows through.

Electric current, through high electrical resistance, results in heat due to the friction between the material and the electrons that are flowing through the material. Tungsten is used for incandescent bulb filaments because it is extremely resistant to melting at high temperatures. It also does not burn, because gas is injected into incandescent bulbs to eliminate all oxygen.