If you think about an asylum, there are two kinds of people in it: staff and patients. We aren’t sure which one [Nick Lucid] is in the latest The Science Asylum video that tries to answer the question: does electricity really flow like water?
If you think about it, that isn’t such a strange question. We talk about electrical current — just like current in a stream. Many introductory books on electricity try to relate voltage to water pressure, electric current to water flow, and resistance to changes in pipe volume. Of course, you probably figured out that analogy doesn’t — ahem — hold water to some level of detail, but just how far off is it? We won’t spoil the surprise so you can watch the video to find out, but there were several really interesting tidbits. How fast do electrons drift through a conductor? The speed of light? Actually, no — remember, drift velocity is the average speed of an individual electron, not the speed of the electric current.
So if electrons aren’t moving at the speed of light, how is it we make all kinds of circuits and antennas that rely on the speed of light? The video shows why this works, even if individual electrons don’t move nearly as fast. In fact, the speed is so slow that electrons in an AC circuit hardly move at all since they just pace back and forth a very small amount on each half cycle.
One of the things that complicates the picture compared to when many of us were in school is we now understand a lot more about the quantum nature of things at this scale and that’s always confusing. Surprisingly, the video also gives some intuition about skin effect that might come in handy.