
In the late 80’s and early 90’s, there was a great show called secret life of machines. The BBC program spent a half-hour each week taking a look at the inner workings of a different everyday device, covering things from the car to the vacuum cleaner. The show was delivered with a trademark quirkiness, and often involved the hosts Tim and Rex re-creating homemade versions of various items, or carrying out experiments using household objects.
The show stands up remarkably well, even 15 years later. The Lightbulb episode, in particular, is a very good primer on electric (and I suppose non-electric) lighting technologies. Of particular interest to me was the bit explaining much of the energy-efficient lighting technologies, like Fluorescent lamps and sodium lights used in streetlamps. In particular, the host Tim Hunkin makes a very good demonstration of why the light quality of bulbs differ at the 19:55 mark (I can’t link right to that point, unfortunately, but it’s definitely worth a look). Below is a still, where he shows a breakdown of the spectrum of a compact fluorescent bulb using a type of prism, showing it to be banded and segmented rather than fluid.

Compact fluorescent bulbs have of course improved a lot in the last 15 or so years. They’re getting close to being indistinguishable from conventional bulbs, and they end up saving a lot of money over time. Still, this episode does a lot to explain exactly how they work, and why they’re important.
Google Video also has many more episodes on a wide variety of topics. All are worth taking a look.