Physicists at Tsinghua University in China and Louisiana State University are currently experimenting with prototypes for a new kind of light bulb. In these prototypes, called SWNT (single-walled nanotube) bulbs, the tungsten filament of a conventional incandescent light bulb is replaced by a filament made of carbon nanotubes.

Carbon nanotubes are microscopic cylinders of carbon which have several remarkable properties. They are extremely efficient conductors of energy, as well as being one of the strongest materials known to man. They are exceedingly durable, and can withstand temperatures of up to 2,800 degrees Celsius. Because of these rare traits, many scientists believe that carbon nanotubes could provide a practical alternative to traditional tungsten for light bulb filaments.

In conventional light bulbs, the thickness of the tungsten generally varies across the length of the filament, resulting in "hot spots" which are prone to breakage. When the filament breaks, the light bulb burns out. Because of the inherent cylindrical shape of a carbon nanotubes, filaments made from them are much more uniform in thickness than tungsten filaments, thus eliminating hot spots. This suggests that nanotubes could be used to develop a light bulb that would last almost indefinitely.

In addition, because carbon nanotubes so efficiently conduct energy, SWNT bulbs emit more light per volt than their tungsten-filament counterparts. Therefore, an SWNT bulb uses less energy than a conventional light bulb of the same brightness.

Though more work needs to be done to perfect their design, scientists estimate that nanotube light bulbs could be available to the public within a few years.

Tatiana McGarry is a freelance writer who lives in Chicago, IL.

Source: www.isnare.com