How do CFL's work / How are they different from Incandescent Lights?

CFL's are a type of fluorescent lamps. Light is produced by them when an electric current passes between two electrodes called cathodes in a tube filled with low-pressure mercury vapor. It also contains inert gases such as argon and krypton. The electric current passes through the electrodes it excites the mercury vapor in the tube, generating radiant energy, primarily in the ultraviolet (UV) range. The tube consists of phosphor coating on the inside. When the UV radiated by the mercury vapor falls on the phosphor coating, it is converted into visible light. Changing the composition of the phosphor powder inside fluorescent tubes changes the spectrum of light produced. Mercury is present in the lamp in both the phosphor powder and in the vapor. Whereas in incandescent lights, afilament is heated in a vacuum until it glows and gives off light and heat. During this process an enormous amount of energy is wasted as heat.

CFL design details

CFLs have two main components: a gas-filled tube and magnetic or electronic ballast. Electronic ballasts contain a small circuit board with rectifiers, a filter capacitor and usually two switching transistors connected as a high-frequency resonant series DC to AC inverter. The resulting high frequency, around 40 kHz or higher, is applied to the lamp tube. Standard CFLs do not respond well in dimming applications and special lamps are required for dimming service.
CFLs are available in various shapes. The standard shapes of CFL tube are single-turn double helix, double-turn, triple-turn, quad-turn, circular, and butterfly. 

1.      CFLs consumes one third of energy than standard incandescent bulbs to produce same amount of light.
2.      CFLS can last about 6 times longer.

3.      CFLs produce 70 percent less heat than standard incandescent bulbs.

1.      Skin cancer risk, due to leaking UV radiation.
2.      Like all fluorescent lamps, CFLs contain mercury, which complicates their disposal and if the bulbs are broken indoors, does present a health risk, especially to small children.
3.      Costly