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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
rs20:
Totally plugging my own stuff here, but here's a post I wrote nearly 10 years ago on the topic of seeing magnetism as a consequence of electric field + relativity: https://www.rs20.net/w/2012/08/how-do-magnets-work-magnetism-electrostatics-relativity/
aetherist:
Thanx to rs20 & TimFox re Einsteinian magnetism. I found some calcs that i did recently re Veritasium's youtube, so i well regurgitate that as per below.
I had a look at Veritasium's youtube footage re relativistic magnetic fields (see below). His numbers don’t work.
Derek says that the charges in a wire appear closer together due to length contraction due to Einstein's special relativity.
He says that the v/c of the electron drift velocity is typically 0.000 000 000 1% (which is 1 by 10^-12 of c).
Speed c is 3 by 10^11 mm/s – hence his electron drift velocity is 0.3 mm/s. However i think that 0.03 mm/s is more typical (but i will stick with his 0.3 mm/s).
Anyhow, the length contraction factor for 0.3 mm/s is (1-vv/cc)^0.5 (where v/c is 1 by 10^-12).
This equals i think…. (0.999 999 999 999 999 999 999 999)^0.5…. (which is 24 decimals ^0.5).
This equals i think….. 0.999 999 999 999 999 999 999 999 5……… (which is 25 decimals).
So, a 1 m length of wire (moving at 0.3 mm/s) contracts to 0.999 999 999 999 999 999 999 999 5 m.
So, the loss in length is 0.000 000 000 000 000 000 000 000 5 m (which is 5.0 by 10^-25 m).
I had previously calculated that there is 0.077 kg of free electrons in one cubic metre of copper.
Hence there is 7.7 by 10^-8 kg of free electrons in a wire of 1 mm2 if the wire is 1 m long.
One electron has a mass of 9.11 by 10^-31 kg.
Hence that 1 m of wire contains 8.5 by 10^22 free electrons.
Each 1.0 by 10^-25 m length of the wire contains 8.5 by 10^-3 electrons.
The lost length contains 5 times as much -- ie 4.25 by 10^-2 electrons – ie 0.0425 electrons – ie 1/23.5 electrons.
If so then the length contraction in 23.5 m of wire would involve just 1 whole solitary lonely electron.
I doubt that this weak relativistic length contraction effect would explain the magnetic field around the wire [ignoring for now that Einsteinian length contraction is baloney].
Or have i erred?
Another thing, Veritasium applies the length contraction gambit 2 times, thus doubling his effective charge – he uses it to give the "stationary" electrons a wider spacing – whilst at the same time giving the positively charged "drifting" nuclei a closer spacing – no, u can't do that.
How Special Relativity Makes Magnets Work
3,065,179 viewsSep 23, 2013 Veritasium 11.2M subscribers
MinutePhysics on permanent magnets: https://www.youtube.com/watch?v=hFAOXd...
Magnetism seems like a pretty magical phenomenon. Rocks that attract or repel each other at a distance - that's really cool - and electric current in a wire interacts in the same way. What's even more amazing is how it works. We normally think of special relativity as having little bearing on our lives because everything happens at such low speeds that relativistic effects are negligible. But when you consider the large number of charges in a wire and the strength of the electric interaction, you can see that electromagnets function thanks to the special relativistic effect of length contraction.
In a frame of reference moving with the charges, there is an electric field that creates a force on the charges.
But in the lab frame, there is no electric field so it must be a magnetic field creating the force.
Hence we see that a magnetic field is what an electric field becomes when an electrically charged object starts moving.
I was inspired to make this video by Prof. Eric Mazur http://mazur.harvard.edu/emdetails.php
Huge thank you to Ralph at the School of Physics, University of Sydney for helping us out with all this magnetic gear. Thanks also to geology for loaning the rocks. This video was filmed in the studio at the University of New South Wales - thanks to all the staff there for their time and support.
6,568 Comments
aetherist:
--- Quote from: rs20 on February 17, 2022, 02:38:19 am ---Totally plugging my own stuff here, but here's a post I wrote nearly 10 years ago on the topic of seeing magnetism as a consequence of electric field + relativity: https://www.rs20.net/w/2012/08/how-do-magnets-work-magnetism-electrostatics-relativity/
--- End quote ---
I think that a major problem with relativistic magnetism around a wire is that if the wire had a dia of say 0.1 mm, then a length with 1 mm, then a length with 10 mm, the areas would have the ratio 1 to 100 to 10,000, in which case the drift speeds would be in that ratio (for the same amperage), in which case the length contractions would be in the ratios 100 to 10 to 1, in which case the electrostatic forces near each of the 3 lengths would be in thems ratios. While the conventional calc of the theoretical magnetic force demands the ratios 1 to 1 to 1.
I think i can smell another elephant.
Or have i erred?
SandyCox:
--- Quote from: aetherist on February 16, 2022, 03:40:20 am ---
--- Quote from: adx on February 16, 2022, 02:05:55 am ---That's cool.
What if an experiment were to give a result vastly closer to zero change in speed than the predicted slowdown due to surface hugging of the macroscopic threadform?
Would you consider a medium frequency (say 100MHz or 1 GHz) result for say the central conductor in a coax threaded vs 'smooth'?
Would you accept that increased loss is different from increased delay?
Not saying I have the intention or equipment, just wondering how you would handle a confounding result if it were to eventuate.
Similar for the painted antenna.
--- End quote ---
I reckon one strike & my new (electon) electricity is out. It has to tick every box.
Delays sound simple to me. If screw threads didn’t have a delay or a delay that was not 100% predictable then i would be forced to abandon electons & invoke my roo-tons, which are photons that hop along the surface.
Which reminds me, William Beaty at one time invoked a leapfrogging em field, that leaped out of a wire (where the speed of the em was only 10 m/s), into the insulation (where the speed was 2c/3), & landing back in the wire. Hence he might be happy with my roo-tons (but might prefer to call them frogtons). I could meet him halfway, hoptons.
Losses i don’t understand, sounds complicated.
Effect of frequency sounds complicated, over my head.
Co-axial cables might be over my head too.
Painting a rod would be interesting.
We could paint longi stripes, & see what happens (to the speed of electricity). Adding one at a time, until coverage is 100%.
We could paint transverse stripes, ie one at a time, until the coverage was 100%.
We could have very thin paint, eg less than 1000 nm thick, to find the critical thickness (where the enamel is no longer 100% effective).
Painting a threaded rod would be interesting. A double whammy of slowing.
But, getting back to coaxial cables. Tony Wakefield did an experiment using a coaxial cable as a capacitor. This discharged at a half of the predicted voltage (ie a half of the voltage predicted by old electricity) taking double the predicted time (ie double the time predicted by old electricity). But as we all know the half voltage & doubled time accords exactly with my new (electon) electricity, where a half of the electons (in a capacitor) are going each way at any one time (ie before the discharge switch is closed). I think he used 18 m of coax, a 9 V battery, a mercury reed switch, & a 350 MHz scope.
http://www.ivorcatt.co.uk/x37p.htm
Erik Margan repeated Wakefield's X.
http://www.ivorcatt.co.uk/x726.pdf
--- End quote ---
Is this the example where "old electricity" doesn't predict the discharge rate of the capacitor correctly?
aetherist:
--- Quote from: SandyCox on February 17, 2022, 08:21:00 am ---
--- Quote from: aetherist on February 16, 2022, 03:40:20 am ---
--- Quote from: adx on February 16, 2022, 02:05:55 am ---That's cool.
What if an experiment were to give a result vastly closer to zero change in speed than the predicted slowdown due to surface hugging of the macroscopic threadform?
Would you consider a medium frequency (say 100MHz or 1 GHz) result for say the central conductor in a coax threaded vs 'smooth'?
Would you accept that increased loss is different from increased delay?
Not saying I have the intention or equipment, just wondering how you would handle a confounding result if it were to eventuate.
Similar for the painted antenna.
--- End quote ---
I reckon one strike & my new (electon) electricity is out. It has to tick every box.
Delays sound simple to me. If screw threads didn’t have a delay or a delay that was not 100% predictable then i would be forced to abandon electons & invoke my roo-tons, which are photons that hop along the surface.
Which reminds me, William Beaty at one time invoked a leapfrogging em field, that leaped out of a wire (where the speed of the em was only 10 m/s), into the insulation (where the speed was 2c/3), & landing back in the wire. Hence he might be happy with my roo-tons (but might prefer to call them frogtons). I could meet him halfway, hoptons.
Losses i don’t understand, sounds complicated.
Effect of frequency sounds complicated, over my head.
Co-axial cables might be over my head too.
Painting a rod would be interesting.
We could paint longi stripes, & see what happens (to the speed of electricity). Adding one at a time, until coverage is 100%.
We could paint transverse stripes, ie one at a time, until the coverage was 100%.
We could have very thin paint, eg less than 1000 nm thick, to find the critical thickness (where the enamel is no longer 100% effective).
Painting a threaded rod would be interesting. A double whammy of slowing.
But, getting back to coaxial cables. Tony Wakefield did an experiment using a coaxial cable as a capacitor. This discharged at a half of the predicted voltage (ie a half of the voltage predicted by old electricity) taking double the predicted time (ie double the time predicted by old electricity). But as we all know the half voltage & doubled time accords exactly with my new (electon) electricity, where a half of the electons (in a capacitor) are going each way at any one time (ie before the discharge switch is closed). I think he used 18 m of coax, a 9 V battery, a mercury reed switch, & a 350 MHz scope.
http://www.ivorcatt.co.uk/x37p.htm
Erik Margan repeated Wakefield's X.
http://www.ivorcatt.co.uk/x726.pdf
--- End quote ---
Is this the example where "old electricity" doesn't predict the discharge rate of the capacitor correctly?
--- End quote ---
I think that old electricity say that discharge follows a nice curve.
But new electricity says a step.
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