A fluorescent lamp is not easy to make, which is one of the reasons that it happens to be more expensive than incandescent bulbs, at least at the start. Over time, of course, the lower energy usage is going to help those lights pay for themselves though. In order to make one of the lamps, you have to have a bulb, a glass tube that has mercury vapor at a low pressure inside of it. Along the inside of the tube, they coat it with a phosphorous substance.
In each of the ends of the lamp is a coiled tungsten metal filament. When you turn on the light and electricity starts to flow through them, it begins to agitate the mercury atoms thanks to the moving electrons, which is what creates the light. This creates UV light, which would not be beneficial as a lamp. This is why the makers coat the inside of the tubes with the phosphorescent material.