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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
HuronKing:
--- Quote from: aetherist on March 23, 2022, 01:12:30 am ---Purcell ch5 is no better. He in effect confirms that STR infers that there is no limit to the hi-strength of a magnetic field around a current carrying wire if u make the wire thinner & thinner. And, no limit to the lo-strength if u make the wire thicker & thicker. All wires carrying the same say one Amp.
What to call it? Einstein's Magnetism Catastrophe – might do.
--- End quote ---
Uhh, no?
Is this it? Is this the culmination? That at the end of all this... you don't understand Ohm's Law or Ampere's Law or even the meaning of uniform current density?
Changing the thickness of the wire but maintaining the same current (meaning you had to change the strength of the E-field that created the current in order to keep it constant) won't change the magnetic field strength at some distance r away from the surface of the conductor. Not in relativity and not in Ampere's Law either.
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magin.html#c1
You'll notice that Ampere's Law makes no statement about the thickness of wires versus magnetic field strength - just how far you are FROM THE CENTER of a Gaussian loop and how much current is enclosed by the Gaussian loop that the current penetrates through. Ampere's Law and Relativity are true whether wires are there or not! They're laws of nature. Magnetic fields exist in space even when wires aren't around....
It's unfortunate that Ampere's Law is always taught in the context of current-carrying wires. I can make currents in empty space with an electron gun and exactly define the magnetic field strengths around them depending on the density of the electron stream and their velocities - BTW this is how cathode-ray tube TV works. If special relativity were wrong, the images on old TVs could never be in focus:
https://www.pbs.org/newshour/science/tv-radar-guns-and-other-technology-linked-to-einsteins-theories-of-relativity
Refer to example 5.4:
https://openstax.org/books/university-physics-volume-3/pages/5-3-time-dilation
Anyways, I've digressed because there are just so many ways you're wrong about everything.
In Chapter 5 and later into Chapter 6 of Purcell, they used relativity to derive an identical expression of Ampere's Law starting with Gauss' Law and Coulomb's Law because they are already Lorentz invariant (which Purcell takes pains to explain). Consistent with experiment and consistent with mathematics. The only catastrophe here is you.
--- Quote ---Einstein's MC can be added to Einstein's TC (Twins Catastrophe)(which i see that Steinmetz ignored in his 4 lectures).
--- End quote ---
LOL calm down. He was introducing relativity to people who had never heard of it before and didn't have a strong mathematical background. And there is nothing catastrophic about the twin paradox - it ain't even a paradox, really.
--- Quote ---I see that Steinmetz too called the MMX null, when in fact the MMX showed a 6 km/s aetherwind, corrected to 8 km/s by Munera (using the proper averages), corrected to about 380 km/s by Cahill (using the proper calibration).
--- End quote ---
Yea, cause Michelson couldn't report etherwind within his own margin of error. We've been over this. :blah: :blah: :blah:
--- Quote ---In 1925-33 approx Miller & Morley repeated the Michelson & Morley MMX & found an aetherwind of about 240 km/s, later corrected to 400 km/s by Cahill using the proper calibration. But Steinmetz died in 1923 (either from shame re the Einsteinian Twins Catastrophe, or from anxiety re the Einsteinian Magnetic Catastrophe), hence he did not have the benefit of Miller's improved MMX.
--- End quote ---
And now you're being a tool - this isn't funny. Steinmetz had health problems his whole life and he died far too young. I wish he had lived through the quantum revolution. He might've even lived to see the invention of the transistor under different circumstances.
But I am glad to see you've completely reversed course on co-opting Steinmetz for your lunacy while just hours earlier you were tentatively hoping he might back up your crankery. Steinmetz was no crank. In fact, he was a true scientist. He lived through the Ether Dark Ages, learned about relativity, realized what a brilliant and coherent theory it is, and said this about people who cling to ether,
--- Quote ---Thus the conception of the ether; is one of those untenable hypotheses which have been made in the attempt to explain some difficulty. The more it is studied and conclusions drawn from it, the more contradictions we get, and the more unreasonable and untenable it becomes. It has been merely conservatism or lack of courage which has kept us from openly abandoning the ether; hypothesis. The belief in an ether; is in contradiction to the relativity theory, since this theory shows that there is no absolute position nor motion, but that all positions and motions are relative and equivalent.
--- End quote ---
Charles P. Steinmetz p.16
Ya hear that? Steinmetz thinks you're a coward. >:D
--- Quote ---Re Einstein's Magnetism Catastrophe. Einsteinist's always invoke an infinitely long wire. Did u ever wonder why it was infinitely long? Allow me to tell u. It was infinitely long koz a finitely long wire duznt work.
--- End quote ---
You're a civil engineer (apparently I guess from what you said pages ago) so I'll forgive this particular idiocy due to lack of electrical physics/mathematics education on your part.
But Ampere's Law as conventionally written doesn't work directly with finite length wires either because there is no longer charge conservation. You have to account for the boundary conditions where discontinuity exists - this breaks the symmetry of the problem and makes the integrations harder. Not impossible - just harder:
http://www.phys.uri.edu/gerhard/PHY204/tsl216.pdf
https://scholarworks.merrimack.edu/cgi/viewcontent.cgi?article=1016&context=phy_facpub
https://opentextbc.ca/universityphysicsv2openstax/chapter/amperes-law/
--- Quote ---Consider using Ampère’s law to calculate the magnetic fields of a finite straight wire and of a circular loop of wire. Why is it not useful for these calculations? In these cases the integrals around the Ampèrian loop are very difficult because there is no symmetry, so this method would not be useful.
--- End quote ---
OpenText BC
This works the same way in relativity but the mathematics are, again, more complicated and mostly outside the purview of Purcell's introductory text (too hard for you, I'm sorry).
--- Quote ---The attraction (or repulsion) tween 2 finite parallel wires can't increase with relative speed, koz STR length contraction lessens the spacings tween electrons or protons, but it can't add or subtract electrons or protons from the wire(s).
What to call this? Einstein's Catastrophe For Wires With Finite Length.
It means that finite lengths of wire can't have magnetism.
--- End quote ---
They do - you just don't know how to calculate them.
How do I know you can't? Try solving the homework problems in Purcell Chapter 5 or Chapter 6 (exercise 6.5 is particularly good as is 6.28). Go ahead - try. I won't wait.
In the meantime, I have my own homework to do (and to grade).
aetherist:
--- Quote from: HuronKing on March 23, 2022, 04:41:18 am ---
--- Quote from: aetherist on March 23, 2022, 01:12:30 am ---Purcell ch5 is no better. He in effect confirms that STR infers that there is no limit to the hi-strength of a magnetic field around a current carrying wire if u make the wire thinner & thinner. And, no limit to the lo-strength if u make the wire thicker & thicker. All wires carrying the same say one Amp.
What to call it? Einstein's Magnetism Catastrophe – might do.
--- End quote ---
Uhh, no?
Is this it? Is this the culmination? That at the end of all this... you don't understand Ohm's Law or Ampere's Law or even the meaning of uniform current density?
Changing the thickness of the wire but maintaining the same current (meaning you had to change the strength of the E-field that created the current in order to keep it constant) won't change the magnetic field strength at some distance r away from the surface of the conductor. Not in relativity and not in Ampere's Law either.
[url]http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magin.html#c1[/url]
You'll notice that Ampere's Law makes no statement about the thickness of wires versus magnetic field strength - just how far you are FROM THE CENTER of a Gaussian loop and how much current is enclosed by the Gaussian loop that the current penetrates through. Ampere's Law and Relativity are true whether wires are there or not! They're laws of nature. Magnetic fields exist in space even when wires aren't around....
It's unfortunate that Ampere's Law is always taught in the context of current-carrying wires. I can make currents in empty space with an electron gun and exactly define the magnetic field strengths around them depending on the density of the electron stream and their velocities - BTW this is how cathode-ray tube TV works. If special relativity were wrong, the images on old TVs could never be in focus:
[url]https://www.pbs.org/newshour/science/tv-radar-guns-and-other-technology-linked-to-einsteins-theories-of-relativity[/url]
Refer to example 5.4:
[url]https://openstax.org/books/university-physics-volume-3/pages/5-3-time-dilation[/url]
Anyways, I've digressed because there are just so many ways you're wrong about everything.
In Chapter 5 and later into Chapter 6 of Purcell, they used relativity to derive an identical expression of Ampere's Law starting with Gauss' Law and Coulomb's Law because they are already Lorentz invariant (which Purcell takes pains to explain). Consistent with experiment and consistent with mathematics. The only catastrophe here is you.
--- Quote ---Einstein's MC can be added to Einstein's TC (Twins Catastrophe)(which i see that Steinmetz ignored in his 4 lectures).
--- End quote ---
LOL calm down. He was introducing relativity to people who had never heard of it before and didn't have a strong mathematical background. And there is nothing catastrophic about the twin paradox - it ain't even a paradox, really.
--- Quote ---I see that Steinmetz too called the MMX null, when in fact the MMX showed a 6 km/s aetherwind, corrected to 8 km/s by Munera (using the proper averages), corrected to about 380 km/s by Cahill (using the proper calibration).
--- End quote ---
Yea, cause Michelson couldn't report etherwind within his own margin of error. We've been over this. :blah: :blah: :blah:
--- Quote ---In 1925-33 approx Miller & Morley repeated the Michelson & Morley MMX & found an aetherwind of about 240 km/s, later corrected to 400 km/s by Cahill using the proper calibration. But Steinmetz died in 1923 (either from shame re the Einsteinian Twins Catastrophe, or from anxiety re the Einsteinian Magnetic Catastrophe), hence he did not have the benefit of Miller's improved MMX.
--- End quote ---
And now you're being a tool - this isn't funny. Steinmetz had health problems his whole life and he died far too young. I wish he had lived through the quantum revolution. He might've even lived to see the invention of the transistor under different circumstances.
But I am glad to see you've completely reversed course on co-opting Steinmetz for your lunacy while just hours earlier you were tentatively hoping he might back up your crankery. Steinmetz was no crank. In fact, he was a true scientist. He lived through the Ether Dark Ages, learned about relativity, realized what a brilliant and coherent theory it is, and said this about people who cling to ether,
--- Quote ---Thus the conception of the ether; is one of those untenable hypotheses which have been made in the attempt to explain some difficulty. The more it is studied and conclusions drawn from it, the more contradictions we get, and the more unreasonable and untenable it becomes. It has been merely conservatism or lack of courage which has kept us from openly abandoning the ether; hypothesis. The belief in an ether; is in contradiction to the relativity theory, since this theory shows that there is no absolute position nor motion, but that all positions and motions are relative and equivalent.
--- End quote ---
Charles P. Steinmetz p.16
Ya hear that? Steinmetz thinks you're a coward. >:D
--- Quote ---Re Einstein's Magnetism Catastrophe. Einsteinist's always invoke an infinitely long wire. Did u ever wonder why it was infinitely long? Allow me to tell u. It was infinitely long koz a finitely long wire duznt work.
--- End quote ---
You're a civil engineer (apparently I guess from what you said pages ago) so I'll forgive this particular idiocy due to lack of physics/mathematics education on your part.
But Ampere's Law as conventionally written doesn't work directly with finite length wires either because there is no longer charge conservation. You have to account for the boundary conditions where discontinuity exists - this breaks the symmetry of the problem and makes the integrations harder. Not impossible - just harder:
[url]http://www.phys.uri.edu/gerhard/PHY204/tsl216.pdf[/url]
[url]https://scholarworks.merrimack.edu/cgi/viewcontent.cgi?article=1016&context=phy_facpub[/url]
[url]https://opentextbc.ca/universityphysicsv2openstax/chapter/amperes-law/[/url]
--- Quote ---Consider using Ampère’s law to calculate the magnetic fields of a finite straight wire and of a circular loop of wire. Why is it not useful for these calculations? In these cases the integrals around the Ampèrian loop are very difficult because there is no symmetry, so this method would not be useful.
--- End quote ---
This works the same way in relativity but the mathematics are, again, more complicated and outside the purview of Purcell's introductory text (too hard for you, I'm sorry).
--- Quote ---The attraction (or repulsion) tween 2 finite parallel wires can't increase with relative speed, koz STR length contraction lessens the spacings tween electrons or protons, but it can't add or subtract electrons or protons from the wire(s).
What to call this? Einstein's Catastrophe For Wires With Finite Length.
It means that finite lengths of wire can't have magnetism.
--- End quote ---
They do - you just don't know how to calculate them.
How do I know you can't? Try solving the homework problems in Purcell Chapter 5 or Chapter 6. Go ahead - try. I won't wait.
In the meantime, I have my own homework to do (and to grade).
--- End quote ---
Michelson found a signal. Miller used Michelson's gizmo & found a signal. Their margin for error was acceptable. The argument re margin for error boils down to how to treat the apparent noise. I have explained that the supposed noise identified by Roberts was in fact non-wanted signal, which Demjanov & me myself have explained. It was not error, it was signal, albeit non-wanted signal(s) (ie without a known calibration), & was quite correctly simply deducted by averaging out. Altho Michelson's method of averaging was too simple, as pointed out by Munera, who corrected Michelson's 6 km/s to 8 km/s. Michelson & Morley were looking for 30 km/s (ie Earth's orbital speed), & for some reason they called their result null, when it clearly wasn’t null. And Cahill in 2001 derived the correct calibration which corrected the 8 km/s to 340 km/s (i can't remember the exact number), whereas we now know that the aetherwind is today almost 500 km/s.
The STR magnetic field & the Ampere magnetic field can't have an identical expression. And, the attempted invoking of STR is an attempt to use Lorentz variance, it is not based on Lorentz invariance.
I agree that an electron beam has an Amperage & a magnetic field. And it duznt need a dia for the wire.
But STR needs a dia koz the dia determines the ave drift velocity V, to insert into the standard equation for gamma for the supposed length contraction of the ave electron spacing.
If Einsteinist's find some way of invoking some kind of time dilation or somesuch to wave away the need for a dia due to some perverted form of Lorentz invariance then that would not surprise me.
I feel sorry re Steinmetz's poor health & early death at 58 in 1923. Had he lived i feel sure that he would have joined lots of other geniuses (eg Dingle & Silberstein)(& Einstein hizself) in realizing that STR & GTR were krapp, ie after earlier being possibly the No1 & No2 apostles of Einstein.
Einstein divorced STR, & i wonder whether he ever recanted re the STR cause of the magnetic field. He certainly recanted re relativistic mass (but in 1921 Steinmetz was in love with relativistic mass).
The Twins Catastrophe is not a paradox. Einstein couldn’t ever satisfactorily wave away the Twins Catastrophe. I think that the best that he could come up with is to invoke acceleration, & to invoke some kind of time dilation memory caused by an earlier acceleration (believe it or knot). In the modern era i see that there has been a fresh attempt to raise the catastrophe to the status of a paradox (lots of this stuff on youtube)(ugh).
I agree that it is difficult to come up with sensible simple practical models & gedankens of circuits of finite wires etc that can help in an argument re the pros & cons of STR & Ampere & magnetic fields.
Aether comes to the rescue in solving the Faraday Disc Paradox (Faraday, 1831). It is a paradox for aetherists, but is a catastrophe for non-aetherists. I wonder whether Steinmetz ever spent time on this. Steinmetz died in 1923. Did Heaviside spend time on it? Heaviside died in 1925. Faraday died in 1867.
https://en.wikipedia.org/wiki/Faraday_paradox#:~:text=The%20Faraday%20paradox%20or%20Faraday's,is%20a%20non%2Dzero%20EMF.
HuronKing:
--- Quote from: aetherist on March 23, 2022, 06:23:18 am ---
Michelson found a signal. Miller used Michelson's gizmo & found a signal. Their margin for error was acceptable. The argument re margin for error boils down to how to treat the apparent noise. I have explained that the supposed noise identified by Roberts was in fact non-wanted signal, which Demjanov & me myself have explained. It was not error, it was signal, albeit non-wanted signal(s) (ie without a known calibration), & was quite correctly simply deducted by averaging out. Altho Michelson's method of averaging was too simple, as pointed out by Munera, who corrected Michelson's 6 km/s to 8 km/s. Michelson & Morley were looking for 30 km/s (ie Earth's orbital speed), & for some reason they called their result null, when it clearly wasn’t null. And Cahill in 2001 derived the correct calibration which corrected the 8 km/s to 340 km/s (i can't remember the exact number), whereas we now know that the aetherwind is today almost 500 km/s.
--- End quote ---
You haven't actually explained anything - all you can do is cling, desperately, to a handful of a cranks whose experiments have never been independently verified and have been summarily dismissed by I and others in this thread. It's boring now. Give up.
8 km/s from Michelson's supposedly "correct" experiment to 500 km/s is a pretty enormous margin of error. Michelson was both wrong... and right to you. His measurements are valid to you... but also off by a factor of 50 in the wrong direction! And you may wonder why Steinmetz had utter contempt for the contradictions of aetherists and called them cowards for refusing to accept the truth.
--- Quote ---The STR magnetic field & the Ampere magnetic field can't have an identical expression.
--- End quote ---
But they do. Purcell showed it. Panofsky & Philips show it. Feynman showed it to but you called him a moron. LOL. Whatever.
--- Quote ---And, the attempted invoking of STR is an attempt to use Lorentz variance, it is not based on Lorentz invariance.
I agree that an electron beam has an Amperage & a magnetic field. And it duznt need a dia for the wire.
But STR needs a dia koz the dia determines the ave drift velocity V, to insert into the standard equation for gamma for the supposed length contraction of the ave electron spacing.
If Einsteinist's find some way of invoking some kind of time dilation or somesuch to wave away the need for a dia due to some perverted form of Lorentz invariance then that would not surprise me.
--- End quote ---
The fact that you agree about cathode-rays and then turnaround to disagree means this is all floundering hogwash because you can't admit the truth.
Purcell's derivation of the magnetic force as a relativistic transformation of an electric charge in motion is independent of diameters of wires. All he needs is the charge density and the distance to the test charge - wires or no wires. This is why the explanation works for the magnetism of CRT electrons and for electrons drifting in a wire. They're both manifestations of the same phenomena - relativity.
--- Quote ---I feel sorry re Steinmetz's poor health & early death at 58 in 1923. Had he lived i feel sure that he would have joined lots of other geniuses (eg Dingle & Silberstein)(& Einstein hizself) in realizing that STR & GTR were krapp, ie after earlier being possibly the No1 & No2 apostles of Einstein.
Einstein divorced STR, & i wonder whether he ever recanted re the STR cause of the magnetic field. He certainly recanted re relativistic mass (but in 1921 Steinmetz was in love with relativistic mass).
--- End quote ---
More lies.
--- Quote ---The Twins Catastrophe is not a paradox. Einstein couldn’t ever satisfactorily wave away the Twins Catastrophe. I think that the best that he could come up with is to invoke acceleration, & to invoke some kind of time dilation memory caused by an earlier acceleration (believe it or knot). In the modern era i see that there has been a fresh attempt to raise the catastrophe to the status of a paradox (lots of this stuff on youtube)(ugh).
--- End quote ---
More and more lies.
--- Quote ---Aether comes to the rescue in solving the Faraday Disc Paradox (Faraday, 1831). It is a paradox for aetherists, but is a catastrophe for non-aetherists. I wonder whether Steinmetz ever spent time on this. Steinmetz died in 1923.
Did Heaviside spend time on it? Heaviside died in 1923. Faraday died in 1867.
https://en.wikipedia.org/wiki/Faraday_paradox#:~:text=The%20Faraday%20paradox%20or%20Faraday's,is%20a%20non%2Dzero%20EMF.
--- End quote ---
OMG. Do you have memory issues? Like, seriously, do you? We've already been through the Faraday Disc pages and pages ago. Did you forget? Or is this like Mad-Libs where you throw random stuff around in here hoping it sounds impressive?
I see you won't even attempt to solve Purcell's homework problems nor can your precious ether even hope to explain how a CRT TV works. You glossed right past those. Catastrophes indeed.
Again, Steinmetz thinks aetherists are cowards. The ether is dead. Stop parading its corpse around. Let it rest in peace. It had a good run over 100 years ago.
HuronKing:
--- Quote ---It is a remarkable fact that the force on the moving test charge does not depend separately on the velocity or density of the charge carriers but only on the product, β0λ0 in our example, that determines the charge transport. If we have a certain current I, say 1 milliamp, it does not matter whether this current is composed of high-energy electrons moving with 99 percent of the speed of light, or of electrons in a metal executing nearly random thermal motions with a slight drift in one direction, or of charged ions in solution with positive ions moving one way, negatives the other. Or it could be any combination of these, as Exercise 5.30 will demonstrate. Furthermore, the force on the test charge is strictly proportional to the velocity of the test charge v. Finally, our derivation was in no way restricted to small velocities, either for the charge carriers in the wire or for the moving charge q. Equation (5.28) is exact, with no restrictions.
--- End quote ---
Purcell p.263
penfold:
--- 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.
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