Measurement and direction of information

[Zeranin]

I looked at the video, and it seems like nonsense to me. The relativity argument relies on the charges moving at near the speed of light, but in any normal conductor they don’t. The electron drift velocity in a conductor is actually quite slow, mush slower than walking speed, so the whole relativity argument becomes nonsense.

It’s very easy to derive and understand the formula for electron drift velocity in a conductor from first principles, and easy to calculate the drift velocity using the said simple formula. An example of drift velocity calculation can be found here :-

http://resources.schoolscience.co.uk/cda/16plus/copelech2pg3.html

This shows  that the drift velocity for a 5A current in a 0.5 mm^2 conductor is a piffling 7.35E-4 m/s, or roughly 0.1 mm/s. That’s at a respectable current density of 10A/mm^2. Even with a water-cooled conductor you are unlikely to exceed 100A/mm^2, so the highest steady drift velocity that you are likely to create is around 1mm/s, or 3.6 meters per hour.

The current density in power station alternators, xformers, transmission lines etc will generally be less than 10A/mm2, which as discussed gives an electron drift speed of 0.1mm/sec. At 50Hz powerline frequency, that means that the electrons move for a distance of only 0.01 seconds x 0.1mm/sec = 0.001mm (1 micron) before the direction is reversed. Therefore the electrons in the windings of a power station alternator will never leave the winding, much less the power station, but just jiggle back and forth by 0.001mm.

Not sure if the above alters your desire to directly measure electron drift velocity in a conductor, or influences how you might choose to do so.

[John Heath]

 slower than walking speed, so the whole relativity argument becomes nonsense.

Yes the slow walk argument. It is so far from the steep end of the Lorentz curve that the effect would be too small. The counter argument that I googled up is the coulomb force is much stronger therefore that little effect is enough. You could also say electrons are jumping around in all directions close to c with a higher probability of jumping in the drift direction. Both these arguments a bit ,, optimistic to put it in a nice way.

 This shows  that the drift velocity for a 5A current in a 0.5 mm^2 conductor is a piffling 7.35E-4 m/s,

I googled 1 mm wire 1 amp 100 u meters per second electron drift velocity which is almost the same as your numbers. That is a very slow walk , ha. 

Not sure if the above alters your desire to directly measure electron drift velocity in a conductor, or influences how you might choose to do so.

I can not live with a knot in a rope. It will haunt for months and months. I suspect you can relate to that. As I said before any attempts to make this measurement with a wire fails as the protons turn the other way when rotating a wire on a turn table. If you stew on it for a bit you will  see the problem. If I could just rotate all the electrons in a 1 mm wire 1 revolution per second the magnetic field would be off the scale if 1 u meter per second is 1 amp. 10,000 amps would be the ball park number.

One thought was bits of conductive tape on the edge of a disk exposed to a 32 KV TV high voltage line. This should pull a few electrons off the tape. When rotating the disk the missing electrons , protons , on the tape will be moving without electrons to counter the effect. What do you think ?   

[Zeranin]

slower than walking speed, so the whole relativity argument becomes nonsense.

Yes the slow walk argument. It is so far from the steep end of the Lorentz curve that the effect would be too small. The counter argument that I googled up is the coulomb force is much stronger therefore that little effect is enough. You could also say electrons are jumping around in all directions close to c with a higher probability of jumping in the drift direction. Both these arguments a bit ,, optimistic to put it in a nice way.

 This shows  that the drift velocity for a 5A current in a 0.5 mm^2 conductor is a piffling 7.35E-4 m/s,

I googled 1 mm wire 1 amp 100 u meters per second electron drift velocity which is almost the same as your numbers. That is a very slow walk , ha. 

Not sure if the above alters your desire to directly measure electron drift velocity in a conductor, or influences how you might choose to do so.

I can not live with a knot in a rope. It will haunt for months and months. I suspect you can relate to that. As I said before any attempts to make this measurement with a wire fails as the protons turn the other way when rotating a wire on a turn table. If you stew on it for a bit you will  see the problem. If I could just rotate all the electrons in a 1 mm wire 1 revolution per second the magnetic field would be off the scale if 1 u meter per second is 1 amp. 10,000 amps would be the ball park number.

One thought was bits of conductive tape on the edge of a disk exposed to a 32 KV TV high voltage line. This should pull a few electrons off the tape. When rotating the disk the missing electrons , protons , on the tape will be moving without electrons to counter the effect. What do you think ?

Like you, I cannot sleep if there is something I don't understand. However, where is the 'knot in the rope' in this case? Now that we have that silly relativistic video out of the way, what more is there to know or understand about electron drift velocity in conductors? Why do you still have an apparent desire to measure drift velocity?

Your proposed experiment should be a valid way of producing moving charge, though I would need to do some back-of-envelope calcs to know if the equivalent current produced would be enough to measure. At a wild guess, you might get equivalent of a few uA. But what are you even trying to measure in the experiment as described?

[John Heath]

Back of envelope calcs ,, I like it. If you see myself working that expression into another  thread you will know where it came from . What am I trying to  measure with this experiment ? I would like to see first hand a forced low drift velocity charge by a rotating turn table producing a measurable magnetic field at 5 to 10 revolutions a second. All theories must be held accountable. In short talk is cheap , lets see the beef. Also there are additional concerns. Addressing these other concerns will be a little wordy , apologies in advance.

I am going the charge the earth to 10 K volts + by sending a bunch of electrons off to a far far place. The equator is turning at 1000 miles per hour. Where I am around 500 miles per hour. There is no reason for the 10 K volt electric field to turn just because the earth is turning. Its just a 10 K volt field coming from the earth. As luck would have it a gravity field is exactly the same as a electromagnetic field. Both travel at c and both gravity field and a electromagnetic field will will not rotate just because the earth is rotating other than a minor hint of frame dragging. Why complicate things by putting gravity on the table? The reason gravity must be put on the table has to do with an experiment done in the early 1970s by Hafele–Keating .

https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment

They flew some atomic clocks around. It turned out east and west bound planes had a difference time dilation. This sounds like a disaster for special relativity however when SR and GR are combined SR is still okay as we are effectively moving through our own gravitational field at 1000 miles per hour when on the equator. As electric field act the same as gravity field then we are moving at 1000 miles per hour through the earth's electric field at the equator. That would be a rather impressive drift velocity for a charge. The probability of the earth having exactly the same amount of electrons as protons is unlikely considering the corona bursts that the sun dumps on us for the northern lights. The earth must have some electric field.

With all that has been said a conclusion on my part is a successful test of a magnetic field caused by the rotation of charges on a turn table will confirm that a low electron drift velocity can produce a measurable magnetic field. However the Hafele–Keating says there must also be an oscillation in that magnetic field equal to the frequency of rotation of the turn table as we move faster and slower with every turn of the table through the earth's electric field at the equator. In my mind this oscillation would be check mate to confirm the Lorentz contraction interpretation of a magnetic field in light of the Hafele–Keating experiment.

All that is left is the details of isolating + or - charges on bits of aluminum tape then rotate the table. The current probe will do the rest providing enough charges can be put on the tape. Need to do some " back of envelope calcs" for 2 p farad tape to surrounding areas with a 10 K volt source with pointed copper edges facing the tape as it passes by on the turn table. The reason for non contact charging of bits of aluminum tape is to use ionized gas to charge it . Air is the path of least resistance for ions. Once on the tape the ions should stick ,, I think ?   

[RandallMcRee]

Its all a bit over my head--but can't you charge one of these dissectable capacitors, separate them and do the experiment??



Seems like the disassembly accomplishes your main goal of separating the charges quite effectively.

Ummm, if you do this--can you make a video? 

[John Heath]

Thanks for posting the video. I enjoyed it. Odd how it is the jar that holds the charge not the plates? While I have your attention all current  cell phone have excellent 3 dimensional hall effect transistors in them. It will display X Y and Z including B for net magnetic field. Perhaps you could start there for your proximity detector. As for my stuff being over your head trust me it is not. If you google to have it explained by someone more qualified than myself it will make more sense.