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Intuitive Guide to Maxwell's Equations

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61–70 of 95 posts

Re: Intuitive Guide to Maxwell's Equations

#61
post #55
post #54

Earlier quoted context omitted.

What's the point of "understanding” QM intuitively if it brings confusion rather than understanding?

You literally can't understand something if you are confused by it. Your question makes no sense.

There is a difference between understanding and “understanding” (intuitively, no less!).

Re: Intuitive Guide to Maxwell's Equations

#62
post #37

According to the epigraph, God said something about D and H, but those were carefully avoided in the text. What's up with that.

Apologies - I didn't even realize that the epigraph expressed some of the equations in terms of flux density! That's what those extra terms mean! I did actually include an explanation of what flux is and how to intuitively derive it within the guide, and you can find it near the integral explanations. Hopefully that helps!

Re: Intuitive Guide to Maxwell's Equations

#63
post #54
post #52

Earlier quoted context omitted.

True generally in Physics as well. What's the point of "understanding" Quantum Mechanics intuitively when you can do computations blindly without it!

What's the point of "understanding” QM intuitively if it brings confusion rather than understanding?

QM can be understood intuitively, the problem is we are still teaching the bullshit 'wave particle duality' when we basically know that fields are what is real.

There's also no such thing as 'observation'. Fields interact by a precise and well-tested mathematical function. That function does have the effect of mutating the state, but why should there be such a thing as pure observation? There's nothing magic about conscious observation.

Re: Intuitive Guide to Maxwell's Equations

#64
post #37

According to the epigraph, God said something about D and H, but those were carefully avoided in the text. What's up with that.

They have to do with the behaviour of the electromagnetic field inside of different materials: https://en.wikipedia.org/wiki/Electric_displacement_field , https://en.wikipedia.org/wiki/Magnetic_field#The_H-field

To get Maxwell's equations in a vacuum, just replace D with εₒE and replace H with B/μₒ.

Re: Intuitive Guide to Maxwell's Equations

#65

Earlier quoted context omitted.

You can even write them in terms of the four-vector A rather than F (related by F = dA) to reduce them to d dA = J.

Discovering that the Maxwell equations can be written in this succinct form is kind of mind-blowing, but I'm wondering whether it provides any additional insight? It seems like one needs to do a significant "unpacking" to actually use the equation or gain insight from it. I would love to hear an explanation of electrodynamics starting with "star ddA = J".

You get new insights, that F is a curvature 2-form. Written in this way it's explicit that EM is also a geometric theory. This observation opens the door to Yang-Mills theories which are behind all the Standard Model.

Re: Intuitive Guide to Maxwell's Equations

#66

It's also interesting once you understand what Maxwell's equations mean to look at their geometric algebra formulation[1]. In particular it makes their use in special and general relativity somewhat more elegant, since the GA form explicitly includes a spacetime component. Of course that page isn't an elementary introduction, it assumes familiarity with GA and the divergence & curl operators, as well as some concepts…

Actually, at the end of the guide, I tried to include an explanation which states that the magnetic field is just a by-product of relativity, and that the equations really only describe one field. A comment on the other approach: the geometric formulation to me looks interesting, but it's still very information dense and a bit un-intuitive! I'll take a look when I get more time though and see if I can re-formulate the ending chapter using this notation. Thank you for the feedback!

Re: Intuitive Guide to Maxwell's Equations

#67

This is awesome. What a concept, identifying the variables in the equations and providing diagrams to show the geometric meaning of the equations. Really wish wikipedia (or some sort of companion website) would similarly present an explanation of the practical meaning of variables and operators in the heavy math pages so that people with an understanding of algebra could understand the formulaic descriptions in addit…

Thanks for the feedback and I agree! I'm going to try to create guides for relativity and quantum mechanics. After I finish those, I'll keep expanding into general math topics, so hopefully those will help as well.

Also an FYI - I made a similar guide to linear algebra which you can also find here:

https://github.com/photonlines/Intuitive-Overview-of-Linear-...

Re: Intuitive Guide to Maxwell's Equations

#68
post #28

Earlier quoted context omitted.

Well, it's not Wikipedia's fault if people producing intuitive content are not contributing to it. It's not like editors go out of their way to remove nice explanations.

I think it is wikipedia's fault, but that it's not far from how it should be. Wikipedia is a secondary source, designed have be a reference taken from primary sources, rather than be a primary source teaching information. It's a weird blurry distinction, but seems to work well. It'd be great to have a pedagogy section that either explicitly linked out to pedagogical primary sources, or a section explicitly designed t…

Wikipedia is a tertiary source. Pedagogical resources are also usually tertiary sources.[0]

[0] https://en.wikipedia.org/wiki/Wikipedia:TERTIARY

Re: Intuitive Guide to Maxwell's Equations

#69
post #5

As a side note there was a historical debate, and the shape of these equations is the end result of the chosen system. In geometric algebra which did not prevail, these are one equation.

Yes, but that's the whole point: math is incredibly information dense. I'm trying to avoid that. Math shouldn't be hard - some concepts are incredibly easy to grasp, but the way that they're taught makes me shudder. It's like seeing code with one letter variable names -written by someone who was scared of losing their job. If you have a way of coming up with an intuitive way of conveying the concepts using geometric algebra, let me know, and I'll be happy to include it in the guide though!

Re: Intuitive Guide to Maxwell's Equations

#70
post #7

These kinds of visual, well thought out explanations of topics which are often taught with terse, obscure and uninviting methods are a gift. On a tangent: I remember asking my Calculus 101 professor what the "intuitive meaning" of divergence and curl was, outside of the formal math and equations. He was shocked that one could ask to sully these perfect mathematical concepts with dirty intuitive reductions. A guide li…

Wikipedia is probably the most obvious modern exemplar of this. The editors of most mathematics articles clearly are much fonder of playing with the equations editor than they are of actually explaining things.

A good description I read of Wikipedia maths articles was that they're like the blackboard of a graduate-level class after everyone has left. All the information is there, but if you're not already familiar with the subject there's no way you'll grasp anything.
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