How does an incandescent light bulb produce light?

Howstuffworks has a pretty thorough yet comprehensible explanation. I'd check that out.

thanks!

Any material that is not perfectly transparent will emit radiation. The radiation is emitted in a continuum and increases with temperature. It is due to the random thermal motion of electrons and nuclei within the material.

There is a much better explanation than mine at
http://en.wikipedia.org/wiki/Thermal_radiation

An incandescent light bulb produces light through a process called incandescence. Here's how it works:

1. Inside the bulb, there is a filament, usually made of tungsten, which is a wire coiled in a spiral shape. Tungsten is used because of its high melting point, allowing it to become white-hot without melting.

2. When you switch on the light bulb, an electric current flows through the filament, heating it up. The filament resists the flow of electricity, and this resistance causes it to heat up and glow.

3. As the filament becomes hotter, it emits light in the visible spectrum. The color of the emitted light depends on the temperature of the filament. Initially, the filament glows red, then orange, yellow, and as it gets hotter, it turns whiter and brighter.

4. The bulb's glass envelope is there to surround the filament and to protect it from oxidation. Since oxygen can make the filament burn out quickly, the glass keeps it in a controlled environment, primarily filled with an inert gas like argon or nitrogen.

It's important to note that incandescent bulbs are not very energy efficient because a significant portion of the energy is converted into heat rather than light. That's why newer technologies like LED lights have become more popular due to their higher efficiency.