Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS

Montage of images and link description. Edison's Miracle of Light Imagemap: linked to kids and home
The Film and More
Imagemap(text links below) of menu items
The American Experience
Music

AC-DC: Inside the Light Bulb

wire | battery | AC generator | light bulb


Inside Light Bulb
Electrons move freely through the wire until they reach the light bulb's filament.
Imagine that you're holding a garden hose -- one with no nozzle attached. With nothing to obstruct the water, it pours out of the hose's end freely. But if you place your thumb over the end of the hose, the water's going to squirt out. The reason it does is because of the resistance created by your thumb.

It works much the same way for a light bulb. Electrons move relatively freely through the wire, then they come to the bulb's filament, which resists the flow of electrons.

The electrons can get through, but not as easily as they can through the wire. The work done overcoming the resistance causes the filament to heat up and to give off light.

wire | battery | AC generator | light bulb
AC/DC | Music

The Film & More | Special Features | Timeline | Gallery | Teacher's Guide
The American Experience | Kids | Feedback | Search | Shop | Subscribe

©  New content 1999-2000 PBS Online / WGBH

Exclusive Corporate Funding is provided by: