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Ohm Overlooked

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This is a case where reading the Wikipedia entry will round out one's impressions left from the article. https://en.wikipedia.org/wiki/Georg_Ohm

After publishing his monograph on the galvanic circuit, he did resign from his position at Bamburg: after which he took up positions at Nuremberg and finally Munich, as a professor of experimental physics.

Also, it's easy to criticize the critics with hindsight, but take a look at his acoustic law https://en.wikipedia.org/wiki/Ohm%27s_acoustic_law which is at best an approximation.

It's easy to confidently think to ourselves, of course we would have accepted Ohm's law! But would we have rejected Ohm's acoustic law as well? What oracle gives us this amazing power?

> What oracle gives us this amazing power?

Hum... Ideally, you could replicate his experiment and verify his findings. That doesn't mean his theory is correct, obviously, but you don't go destroying the career of scientists with valid empiric knowledge just because you disagree with their pick of one of the many theoretical explanations that fit it.

Or, well, people do that, even today, but they shouldn't.

> One of the reasons Ohm’s work was not more readily accepted was because he used contemporary electrical terms that had ambiguous meanings. For example, he did not clearly distinguish between force and electrical potential, and confusingly drew on ideas from Fourier’s theory of heat – he refers to the ‘diffusion’ of electricity.

It's depressing that gatekeeping is such a pervasive human tendency. I wish I could project myself back into the minds of these critics and giggle incessantly about how good ol' `V=IR` has been such a foundation to my world that Ohm's name is utterly inescapable...while these reviewers' dust has all but been lost to the wind.

I still have trouble working out the difference between electromotive force and potential difference. Teachers do a poor job of that one. I imagine it was even more of a blurry muddle to everyone back then.

But if you don't define your variables, an equation becomes a bit useless. Was it really that Ohm didn't use the "gate-kept" language or that he didn't actually know what he was talking about?

With the benefit of history, we know Ohm was more right than wrong. So -- even if these critics where hitting on a very real inconsistency of Ohm's research in their pursuit of the virtue of peer review -- they fell victim to the arrogance of their ivory tower.

The pitch-perfect critique would've had to be "You've got some great work, but this bit here is hard to follow or outright inconsistent". Instead, they shouted him out of the profession because of the surety of their convictions.

This is still a huge problem today because at a certain level most people's benefit proposition switches from the pursuit of discovery to maintenance of the status quo.

Or that other people didn't know what he was talking about.

I know 'gate-keeping' is the Boogeyman de jour but when attempting to communicate scientific ideas to a scientific audience it helps to have the proper vocabulary.

It is much the same as your teachers not being able to bridge the gap between concepts you understand and those needed to understand EMF and PD.

The potential difference can be measured between any two points in a circuit, but EMF is the source of electrical energy such as a battery or generator that produces the potential difference that can be considered to "drive" the circuit.

As I understand it, an EMF has to come from nonelectrical energy, such as chemical, thermal, mechanical, or electromagnetic energy. So if you are drawing your circuit with a battery, you could call that EMF but if you are drawing it with a generic voltage source, you would not call that EMF per se.

That 2nd distinction seems weirdly unreal. Is there an example of a real generic voltage source that only uses electrical energy and not those other types, or are you just referring to an idealization that you might use in a circuit diagram?

Many voltage sources are themselves circuits and the EMF element would be hidden therein.

Hmm. So is it that an EMF can't be carried along conductors like voltage can and is only the original source of the electrical energy with no circuitry?

https://www.electronics-notes.com/articles/basic_concepts/vo...

EMF is a DC voltage present even in an open circuit, when no current is drawn. EMF comes from a cell/battery or DC generator. EMF is the cause; potential difference is the effect.

But potential difference exists when there's no current drawn too. That's just more confusion.

One aspect I'd noticed is that EMF doesn't necessarily have a corresponding potential difference. Eg. a generator with the output short-circuited still has the same EMF as if it was open circuit but potential difference is zero or near-zero across any two points in its windings or circuit.

From my understanding, the problem with Ohm's law is that at the time, they had trouble characterizing internal resistance. You probably noticed that in the article, it is X=a/(b+x), not the familiar V=IR, because they didn't realize yet that internal resistance from the battery was the same as resistance from a length of copper wire. Remember that Kirchhoff's circuit laws came after Ohm and his law became universally recognized.

Everything seems so obvious now, but now, we have accurate multimeters, low internal resistance power supplies and color-coded resistors. They didn't have anything like that in the early 1800s.

Gatekeeping is a thing of course, and it certainly didn't help in Ohm's case, but it is easy to forget the context in which discoveries are made. It is a bit like heliocentrism, obvious now, but when the idea was first introduced, it was actually worse than the theories of that time, based on epicycles, it wasn't just obscurantism.

…a web of naked fancies, which can never find the semblance of support from even the most superficial observation of facts: (and) he who looks on the world with the eye of reverence must turn aside from this... as the result of an incurable delusion, whose sole effort is to detract from the dignity of nature.

is anything more "unfortunately human" than this statement, right here? Both in its creative wording and in its cocksure unwavering wrongness

It would have been the top comment on HN if HN had existed at the time.

Um, "Reduzirten Lange" isn't quite right. It was "Reduzirte Länge" (the modern spelling would be "Reduzierte Länge").

That translates to "reduced length" and was defined by Ohm as the length of a wire divided by it's cross section and specific conductivity.

> In addition to his electrical law, Ohm proposed an acoustic law which proposes that musical notes may be decomposed into a number of pure tones.

Sounds like FFTs! Anyone have a link for more about this?

Ohm proposed it and Helmholtz elaborated it in a book he published about "sound sensations", which I suppose would be called "psychoacoustics" in modern parlance.

I found it online [1] and let Google translate it [2].

[1] https://psychologie.lw.uni-leipzig.de/wundt/opera/helmhltz/t...

[2] https://psychologie-lw-uni--leipzig-de.translate.goog/wundt/...

More precisely the power spectral density, which is always real.

The human ear seems only sensitive to phase when locating sounds binaurally:

https://physics.stackexchange.com/questions/277493/can-human...

I fiddle around with tube amps and Ohms law is about the only math I use in that hobby. It is kind of beautiful in its simplicity

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