Why Do Lightbulbs Burn Out?
The light bulb has been in existence in different forms since the early 1800s. In 1879, Thomas Edison and Joseph Wilson Swan developed the incandescent light bulb independently of each other. These prototypes burned for a very short period of time, at most for just thirteen and a half hours. Does this Spark an idea?
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Construction
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When manufactured, a tungsten filament light bulb is made to uniform specifications. Once the filament has burned for a period of time, the intensity of the light emitted by the bulb is reduced.
Current
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When a light bulb burns out the electrical current passing through the filament remains constant. The filament does not burn at a constant level, which is why the light emitted by a bulb increases significantly before it burns out.
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Air
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The light bulb is usually filled with a gas such as nitrogen or argon to stop the tungsten filament from oxidizing in the air. When air enters the bulb, the oxidized tungsten forms smoke particles and no longer conducts electricity, breaking the electrical circuit.
Time
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The filament within a light bulb works at high temperatures causing the bulb to burn out after a certain period of time by vaporizing the filament.
Structure
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As the filament is used over a long period of time, it becomes brittle and weak as its surface is vaporized. Once the filament becomes brittle, it can break under the stress of the extreme heat that tungsten burns at.
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