How Does an Incandescent Lamp (Light Bulb) Work?

• Inside the glass bulb is a highly thin, coiled wire called the Filament.
• When you flip the switch, a massive electrical current is forced to travel through this extremely thin wire.
• Because the wire is so thin, it offers massive electrical Resistance (friction). This friction causes the wire to heat up violently to an astonishing 2,500°C.
• At this extreme temperature, the metal becomes 'white-hot' and starts violently glowing, throwing visible light into the room.

The filament is made exclusively of a rare metal called Tungsten.

• Why?: Because Tungsten has the absolute highest melting point of any pure metal in the universe (approx. 3,422°C). If you used a normal iron or copper wire, the 2,500°C heat would instantly melt the wire, break the circuit, and the bulb would die in one second.

The glass bulb is completely sealed, and all the normal oxygen air is sucked out.

• Why?: If oxygen touches a 2,500°C hot wire, the wire will instantly catch fire and burn to ashes.
• Instead, the factory fills the bulb with completely inactive, non-reactive gases like Argon and Nitrogen. These gases protect the hot tungsten, stopping it from evaporating or catching fire, allowing the bulb to shine for thousands of hours.

• Incandescent bulbs are a massive disaster for energy efficiency.
• Exactly 90% of the electricity they consume is completely wasted as invisible Heat energy. Only a tiny 10% is actually converted into useful Light.
• Because they waste so much electricity, governments worldwide are legally replacing them with highly efficient LED bulbs.