This seems unnecessarily negative. Teaching analogies don't need to perfectly resemble the system being taught. From a pedagogical perspective, the aim is typically to relate something unfamiliar to something familiar, like water flowing in a pipe, in order to help someone gain footing in a topic.<p>Further connections can be developed mathematically; electric force propagation does obey wave equations, after all. But by then the analogy has served its purpose and should be droppped in favor of more rigorous knowledge development.
>Wikipedia doesn’t stop there; here’s their take on the metal-oxide-semiconductor field-effect transistor (MOSFET):<p>This stood out to me because I have contributed quite a bit to the Wikipedia entry for MOSFET.<p>This illustration does not appear on the Wikipedia entry for a MOSFET: <a href="https://en.wikipedia.org/wiki/MOSFET" rel="nofollow">https://en.wikipedia.org/wiki/MOSFET</a><p>It only appears on the Wikipedia entry for "hydraulic analogy". People do not learn electronics from the Wikipedia entry for "hydraulic analogy".<p>I assert that it is highly likely that not a single human being on earth has ever used the Wikipedia entry for "hydraulic analogy" to learn electronics. It is likely that several people have used that entry to learn about the hydraulic analogy.<p>Then again, I learned electronics from 1988's The Way Things Work, which uses Wooly Mammoths, large stone edifices, and titanically large humans so maybe I was trained on analogy from an early age and learned to not become too attached to them when they start to break down (like how Wooly Mammoths don't exist anymore).<p>edit: oh goodness I just looked it up and the hydraulic analogy for a circuit in The Way Things Work is utterly magnificent, fantabulous, funny, and educational. No mammoths, unfortunately.
My problem with this "hydraulic" analogy (first time I've seen it called that) is that I feel most people don't have that good intuition on hydraulics either, so you are just trading one poorly understood subject with another almost as poorly understood one.<p>Maybe 50 years ago engineering students learning electronics could have had more solid hydraulics background knowledge, but I bet these days more people start from electronics before doing hydraulics.
I learned electronics as a kid from a kit that used a water analogy to describe things. The transistor was described as a vane across a large water canal, connected with a hinge to a smaller vane in a smaller water canal, which allowed it to move up and down. So, a small water current in the small canal could cause a large water current in th large canal. Did it fully and accurately describe the gain characteristics of a real transistor ? No, it didnt. But it would be ridiculous to dismiss it entirely as a learning tool because of it. Overall I think the hydraulic analogy is a very good one, it holds up well and it breaks down only in the face of quantum phenomenon. It allows to understand electricity using concepts children are familiar with. All children like to play with water and have some intuitive sense of it. By the time you care about quantum electronics you can also understand the limitations of the analogy.
Maybe some people just aren't smart enough to understand quantum tunnelling and band gaps, and there's no real better analogy. And even if you do kind of get these, the bad analogies let you remember the standard behaviour so you can reason about what the micro details are.
Analogies aren’t perfect, but they’re still useful. How else are you gonna explain to a grade schooler the difference between voltage and current? This article suggests no alternative.
Counterpoint: Youtuber AlphaPhoenix does a very good job explaining electricity using the hydraulic analogy
<a href="https://www.youtube.com/watch?v=X_crwFuPht4" rel="nofollow">https://www.youtube.com/watch?v=X_crwFuPht4</a>
Related video by Steve Mould about "Spintronics" [1]<p><pre><code> Mechanical circuits: electronics without electricity
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<a href="https://youtu.be/QrkiJZKJfpY" rel="nofollow">https://youtu.be/QrkiJZKJfpY</a><p>[1]: <a href="https://upperstory.com/spintronics/" rel="nofollow">https://upperstory.com/spintronics/</a>
Well, quite a few things can be described using the same mathematics - including switches, resistors, capacitors, and inductive coils. Sure, it is not everything, but well - fluid is fluid, electricity is electricity.<p>For a small simulation, see <a href="http://sjbyrnes.com/1235/" rel="nofollow">http://sjbyrnes.com/1235/</a>.
The problem with the hydraulic analogy is that people take it too far.<p>It’s super useful when describing simple ideas to children or laypeople that only are ever going to look at passive components in dc circuits, or at systems so simple it is unnecessary to distinguish between ac and dc.<p>It quickly falls apart as you involve more complex concepts.<p>But it is very useful at the basic, basic level for developing simple intuitions about voltage, amperage, and resistance. As long as it is used in-scope and with the appropriate caveats, it is very helpful.<p>Taking it too far is the problem. You can’t use Newtonian physics to build a GPS system, and you shouldn’t try to go beyond basic eli5 electricity with the hydraulic model.
The water flow analogies always messed me up because young literal me couldn’t handle reconciling the abstraction with “actually current flows negative to positive”
The hydraulic analogy works great for explaining the basics of electricity to regular people. My stepson doesn't know a transistor from the Trans-Siberian Orchestra, but he needs to know how to use a multimeter to work on his motorcycle.
All models are wrong, but some are useful.<p>I thought you just used hydro on simple RLC circuits, and kept it at that?<p>For semiconductors there's no reason to invent a hydro equivalent that doesn't exist, what's the point? You want a model to be intuitive to the student, and a made-up thing won't be.<p>As you go further with EE, things also tend to turn into a sort of logic gate puzzle rather than a continuous (voltage-current) problem. That's a while other analogy whose limits you also need to know.