Why does a light bulb glow?

1the puzzle

Here's a puzzle: electricity is invisible, so how does pushing it through a wire make bright light? The trick is making the wire fight back.

2the filament

Inside the glass sits a coiled wire called the filament, made of tungsten. Electrons rush through it, but tungsten resists that flow hard.

3resistance heat

That resistance is friction for electrons — it converts electrical energy into heat, and the filament rockets up to about 2,700 degrees Celsius.

4incandescence

Anything that hot glows white — that's called incandescence, the same reason a fireplace ember or a star shines. Heat itself makes light.

5why no burning

But why doesn't the filament just burn up like a matchstick? Because the glass bulb is filled with inert argon gas, not oxygen — nothing to burn.