Back to School Sale
Back to School Sale


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:
Light bulb image by Adrienne Hart-Davis
Tungsten filament close-up image by Dr. Howell at PSU, Material Science Dept.
Light bulb by Adrienne Hart-Davis
Light bulb filament close-up
Answered by: Paul Walorski, B.A., Part-time Physics Instructor
xUmp Science eStore

Science Quote

Paul Dirac Photo

'A theory with mathematical beauty is more likely to be correct than an ugly one that fits some experimental data. God is a mathematician of a very high order, and He used very advanced mathematics in constructing the universe.'

Paul Dirac

- All rights reserved. © Copyright '1995-'2018