Compact Fluorescent Lights work in a similar way to a standard fluorescent tube. The only difference is that the glass tube has been coiled many times allowing the fluorescent light to take up an area as small as an incandescent bulb. Compact fluorescent lights have one metal fitting through which the electricity flows. This differs from older fluorescent tubes which have two metal caps at each end. Inside the coiled glass tube is a mixture of argon (a inflammable gas) and mercury (a type of metal). The inside of the coiled glass is coated with phosphorous powder. When electricity is passed through the metal fitting it travels along a piece of tungsten metal. This acts as an electrode, transmitting the electricity into the gas and mercury. Mercury atoms now begin to vibrate, producing energy in the form of ultraviolet, invisible light. This form of light then interacts with the phosphorous coating causing it to glow, producing the light that we see.