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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
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bsfeechannel:

--- Quote from: adx on March 24, 2022, 02:35:16 am ---That's not what I'm saying, and the fact you can't work out what I mean has been a surprising insight into the way the human mind works.
--- End quote ---

Yes. That's what you're saying, and that's what we are fighting against vigorously.


--- Quote ---Yes, stop studying Cartesian coordinates and silly unit vector formulas. Forget about y. Ignore "functions".
--- End quote ---

And what you'll have is not engineering anymore. We are totally against this kind of movement, because it only serves to create half-assed "engineers" who like to oppose any knowledgeable person that points out their misconceptions.


--- Quote --- Teach the oscilloscope display for what it is.
--- End quote ---

The oscilloscope display is an application of the Cartesian coordenate system. And whoever invented the oscilloscope had that in mind. That's what it is. If you're taught differently, you were duped.


--- Quote ---Prove my misconception. Explain what is the direct relevance of sqrt(-1) to engineering without reference to waffley texts.

--- End quote ---

HuronKing has already done that on the previous page, showing how Steinmetz revolutionized the solution of AC systems with its approach. Engineering is not a simple subject. You can't simplify it beyond a certain point. If you don't want the "waffley texts", do not get near engineering. It's not for you.
aetherist:

--- Quote from: penfold on March 23, 2022, 08:11:45 am ---
--- Quote from: aetherist on March 22, 2022, 11:26:52 pm ---[...]Steinmetz knew that by doubling the dia or by halving the dia then the magnetic field did not change.
But STR said that the magnetic field did change.
STR said that u could get a magnetic field 1000 times stronger by simply using a very thin wire.
--- End quote ---
Define "stronger". The field strength at the surface of wires of different diameters carrying the same current will be different, but the field at a common distance from the center's line of each wire will be the same. STR doesn't say anything to the contrary... I think your arithmetic is in error, at least the "reduction" to proportionalities much earlier on was in error, so I guess whatever led to it was too.
--- End quote ---
I am having a good look at Purcell, re the STR explanation for magnetism near a wire with current.
If Purcell invokes reasonable & internally self consistent aspects of STR (& even praps GTR) then that will be ok.
But i have already seen at least one lie/error. I will explain later today. Really, this should have its own thread. Which would be mainly re the Faraday Disc Paradox.
penfold:

--- Quote from: bsfeechannel on March 24, 2022, 02:51:41 am ---
--- Quote from: penfold on March 24, 2022, 01:42:31 am ---Hang on, that's not a very big question, and the answer is relatively simple. Maths itself is not physical, or it is only as physical as any language in which you can express logic, it's conceptual.
--- End quote ---
Well, if the universe appears to behave consistently logical in certain circumstances, math can provide a convenient description of what is going on and even help to predict future discoveries.

--- End quote ---

Yeah... but it is no more "physical" than a verbal description of a rock, I could describe all the properties of a "rock" in such beautiful detail that suddenly people all over the world suddenly begin to see "rocks". The tangible object to which I attributed the name "rock" and properties of being kinda round, a bit jaggedy, hard... ya know, rock things... will have existed before my description, just more rocks had been identified and unfortunately a few tortoises... until that description gets refined. My verbal description remains purely verbal and not at all physical, it just describes a physical object.

Maths is a descriptive language in which the natural phenomena are described, from those descriptions we can hypothesize, test, and refine new theories... the phenomena, including the big bang, relativity, quantum, etc all existed before humans and maths... yet that curiously happened. The language in which these descriptions are encoded - since it can be communicated verbally... is not exclusively physical.
SandyCox:

--- Quote from: bsfeechannel on March 24, 2022, 01:29:46 am ---
--- Quote from: adx on March 23, 2022, 11:05:16 pm ---bsfeechannel: Seen your post come in. Yes j appears in a couple of places, as an annotation. I was thinking of cheap ass VNAs and Smith charts when I made my claim.

--- End quote ---

Let me get this straight. Because j doesn't appear explicitly on the VNA display, does it mean it is not there? Isn't the display representing a two-dimensional vector space? Aren't VNAs, VECTOR Network Analyzers?

Your point seems moot.

--- End quote ---

The concept of something being "physical" or "real" is in the eye of the beholder.

If you don't believe in complex numbers then just don't use them. You will still be able to do a large part of Electrical and Electronic Engineering by solving the underlying differential equations in the time domain and use a lot of trigonometric identities which will become extremely tedious.

If you chuck out the complex number then you also chuck out Phasor analysis and the whole frequency-domain perspective. You will also loose the Nyquist stability criterion which relies on Cauchy's argument principle. How would you do antenna theory without residues and branch cuts? What about root-locus analysis and design?

I find it strange that you have problems with the Complex numbers but apparently accept the axiom of choice.

And i = j. It is just a difference in notation. Its unclear why we use i for the current shouldn't it be a?

adx:
This is all a bit silly - it started with a gentile troll about i vs j, then we're now back to arguments over half-arsed engineering.


--- Quote from: bsfeechannel on March 24, 2022, 03:15:52 am ---
--- Quote from: adx on March 24, 2022, 02:35:16 am ---That's not what I'm saying, and the fact you can't work out what I mean has been a surprising insight into the way the human mind works.
--- End quote ---

Yes. That's what you're saying, and that's what we are fighting against vigorously.

--- End quote ---

That's what I said;

--- Quote from: adx on March 24, 2022, 02:35:16 am ---Actually no scratch that and I'll remain true to form; it is what I kind of mean ...

--- End quote ---


--- Quote from: bsfeechannel on March 24, 2022, 03:15:52 am ---
--- Quote ---Yes, stop studying Cartesian coordinates and silly unit vector formulas. Forget about y. Ignore "functions".
--- End quote ---

And what you'll have is not engineering anymore. We are totally against this kind of movement, because it only serves to create half-assed "engineers" who like to oppose any knowledgeable person that points out their misconceptions.

--- End quote ---

Uh uh. We'll have the reality of the industrial engineer, what you're complaining about is not misconceptions, but work. So run with the reality, and stop assuming students need to "study" Cartesian coordinate systems (why?!) and teach the concepts.  Maybe then there won't be so many half-assers about. At least they'll get a head start towards reality. All this mathematics and (dare I say it) physics, does no good.

But as with most silly arguments, there are two sides to them. Rather than maximising the troubles, I can try to minimise. I'll allow the students to learn all the words and notation (claptrap), have them study what they'll never use, make it so confusing they can't see the wood for the trees and therefore have to go search for it themselves. That's a proper education. Problem is, you want us all to be mathematicians and physicists, while denigrating the research abilities of engineers, thereby maintaining a false tension with which to maintain your special ideas.

That's why I'm not totally against that type of movement.


--- Quote from: bsfeechannel on March 24, 2022, 03:15:52 am ---
--- Quote --- Teach the oscilloscope display for what it is.
--- End quote ---

The oscilloscope display is an application of the Cartesian coordenate system. And whoever invented the oscilloscope had that in mind. That's what it is. If you're taught differently, you were duped.

--- End quote ---

I was going to let you have that one, it's plausible that chart recorders etc were invented by a mathematician fanboi/grrl of Descartes. Ancient civilisations drew graphs and plotted grain weights through clairvoyance - through the fog of impracticality the letters "T e k t r o n i x" slowly fade into being, and hello what's this, a "graticule"? Looks handy for the cave wall, illuminated by the light of the fire. Then the quick (albeit foggy) glance over to the timebase knob to check if it goes up to 1 moon / div. "Oh well, maybe those future civilisations will just have to wait for the right advances to come along, I hope for their sakes they don't stop studying Cartesian coordinates along the way."


--- Quote from: bsfeechannel on March 24, 2022, 03:15:52 am ---
--- Quote ---Prove my misconception. Explain what is the direct relevance of sqrt(-1) to engineering without reference to waffley texts.

--- End quote ---

HuronKing has already done that on the previous page, showing how Steinmetz revolutionized the solution of AC systems with its approach. Engineering is not a simple subject. You can't simplify it beyond a certain point. If you don't want the "waffley texts", do not get near engineering. It's not for you.

--- End quote ---

All wrong.

Simple question, met with handwaving. Once again, this is about sqrt(-1), not vectors. That expensive thing you showed is called a vector network analyser, not a really complex mathematical network analyser.
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