Old light bulbs, also known as incandescent light bulbs, worked by heating a thin wire filament until it glowed, producing light.
Here's a more detailed breakdown:
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The Filament: At the heart of the bulb was a thin wire filament, typically made of tungsten. Tungsten was chosen because of its high melting point, allowing it to withstand the high temperatures required to produce light without melting.
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Electrical Current: When an electric current passed through the filament, it encountered resistance. This resistance caused the filament to heat up dramatically.
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Incandescence: As the filament's temperature increased, it began to emit light. This emission of light due to heat is called incandescence. The filament glowed, producing visible light.
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The Glass Bulb: The filament was enclosed within a glass bulb. This bulb served two critical purposes:
- Protection from Oxidation: The bulb was either evacuated (a vacuum) or filled with an inert gas, such as argon or nitrogen. This prevented the filament from reacting with oxygen in the air, which would cause it to burn out quickly (oxidize).
- Heat Containment: The bulb helped to contain some of the heat generated by the filament.
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Heat as a Byproduct: A significant portion of the electrical energy was converted into heat rather than light. This is why incandescent bulbs were inefficient, with most of the energy wasted as heat. That's also why they were hot to the touch.
In summary, incandescent bulbs worked by passing electricity through a thin tungsten filament inside a glass bulb, heating the filament to the point where it glowed and produced light.
