Why an electric bulb needs to be vacuumed? Can we light up a bulb in the space without enclosing in the glass bulb?Asked by: Muhammad Nasir
An incandescent light bulb contains a thin wire filament (usually tungsten) that glows hot
when an electric current is run through it. In the presence of oxygen, the filament would
burn up as a result of the high temperature. A glass bulb, then, is used to keep oxygen
away from the filament.
While a vacuum will work, any inert gas that inhibits combustion will also work. Since the vacuum of space would have no oxygen, a bare filament WOULD work as a light bulb without the glass globe.
By the way, even without oxygen present a filament eventually deteriorates as its atoms dissipate. The presence of a halogen gas actually inhibits this deterioration, allowing higher filament temperatures and brighter light bulbs. So the glass globe can also help enhance a bulb's capability.
More info on light bulbs:
Tungsten filament close-up image by Dr. Howell at PSU, Material Science Dept.
Answered by: Paul Walorski, B.A., Part-time Physics Instructor
'The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as in poetry.'