What do light bulbs do?

They use less energy to produce light, and thus save energy and help to save the environment through conserving electricity. The energy efficient light bulb applies fluorescent lighting technology to replace incandescent lighting technology. In the latter, a filament is heated past red hot to white hot to emit useful light. This creates a lot of heat, and is inefficient. The fluorescent tube screws into a socket just like the incandescent lamp, but has electronic circuitry built in to supply the elevated voltages necessary to operate the coiled fluorescent tube. Inside that tube is a gas mixture that is ionized by the voltage, and the ionized gas emits useful light. This process is much more energy efficient than incandescent technology.