Magnet Myths and Misconceptions

[MileHigh]

Tinman:

Okay, for starters, one thing that you have to realize is that experimentally you have an "advantage."  You do the experiment, you see it in front of your own eyes, you try different things, and it all seems pretty clear to you.  Then you give us a few sentences that are typically just results and the barest of any description at all.  Realistically, there are going to be limitations in what you get in terms of feedback and in my head I have to "invent" the setup and the details of what I _think_ might be going on and you can see all the pitfalls that happen on both sides because of that.

If in the future you want to discuss another experiment and explore the theme of "books vs. bench" then the much better way to do that would be to make a good video clip of it.  And I have to fire a warning shot across the bow here.  No verbal description of your circuit.  If you are not willing to make a schematic for tests that involve some kind of circuit then forget it.  You probably have some old clips on your channel where you do a verbal run-down describing 10 to 15 connections and it just doesn't fly.

I read Mark's comments about the pull force and the possible increased curl giving you a higher gradient close to the poles.  That might mean that there is a stronger pulling force only in close proximity to the poles.  It might mean that the attraction force dies off very quickly with distance for the "stronger" coil and for the "weaker" coil the attraction force extends out much further.  We have zero data so it's all an unknown.

Okay now to move on to the "misunderstanding" or whatever you want to call it.

I was basing my entire train of thought on this quote below:

This is totally incorrect,and i know this for fact. This is the difference between those that read books,and those that actually test this very situation with actual devices. Here is a result of this very situation between iron wire and copper wire. Two identical air core coils wound,one with soft iron tie wire(plastic coated),and one with copper wire. Both wires have exact same OD,and same number of turns. Now which do you suppose created the strongest magnetic field when supplied with the same amount of power?-and im talking180%+ stronger.

When you stated "180% stronger" I took that to mean for the copper coil.  Also, why didn't you mention the resistance?  I will be honest with you and state that I was assuming that the difference in resistance between the copper and iron wire was very minimal.  I honestly don't know what the difference is.  If the difference was very minimal, then I could ignore your incorrect reference to power dissipation, and operate with the assumption that the current was approximately the same, within perhaps two or three percent.  So if the current is approximately the same, and the difference in magnetic field strength was 180% greater for one of them, then your reference to power could be ignored.

Note also that we have no idea how you measured the magnetic field strength, I don't think you described it.  In the entire context of this discussion I have to make a ton of assumptions because all that I have from you are a few sentences.

Then it came as a surprise that it's the iron coil with the stronger magnetic field when I thought it would be the copper coil.   Then Mark raised the issue of curl/gradient vs. distance which I honestly hadn't thought about but I can see with 20-20 hindsight is also very important.

Here is the real thing I would like to get across to you:

If the currents in the two coils are significantly different, then the whole test is in a sense BS.  Yes, I am using strong terms.  It's because if you are comparing how two coils of the same geometry will produce a magnetic field, then you want to have the two coils have the same current going through them.  This is something you should know and you should have set up your experiment like this.  Ampere-turns rules and resistance is just a nuisance in this case.

It's like you are saying this to us:  I have two identical copper coils driven from the same voltage source.  The first coil is in series with a 10-ohm resistor and the second coil is in series with a 20-ohm resistor.  Which coil produces the stronger magnetic field?   Can you see what I am saying how that's a bullshit experiment?

After factoring everything in, the real experiment here is to test your two coils with the same current going through each coll.  Then, if you are going to measure the attraction force for each coil, you need to measure what it looks like along the axis of the coil at perhaps five or more distances from a pole.  That puts the two coils on a level playing field.

My final thought which I think you avoided is to go back to the permeability issue.  That is sound and makes sense and I thank Mark for mentioning it.  If you did a proper test setup like I mention above, I have to assume that when you are at a "far distance" from the the poles of the respective coils, that you will measure a stronger magnetic field from the copper coil.  I am not talking pull force, I am talking doing a compass test or something like that to see which field is stronger.  Will you feel a stronger attraction force up close for the iron coil?  What Mark said about the curl sounds plausible.  I would measure the forces and also do an iron filings test to look at the curl and gradient of the magnetic fields from the two coil.

Consider this a kind of iteration on your experiment.   But with 20-20 hindsight it's now apparent to me that you can't do a test yourself and see it and play with it, and give us pop quiz questions without us seeing the same tests ourselves.  That is fundamentally unfair and there are just too many unknowns and limitations.

MileHigh

[MileHigh]

Tinman:

One more thing to mention that's very important:

Pull-force on a test piece of iron is not the same thing as the strength of the magnetic field.

Based on reading your postings, I am still not convinced that you understand this concept.  My impression is that you think [stronger pull force = stronger magnetic field] when that is not necessarily the case.  If you don't get this concept then some of what I stated in my previous big posting may throw you off.

When you probe the pull force around a coil with a test piece of iron that does not directly tell you the strength of the magnetic field.  They are related but they are not the same.

So, do you get this concept?   We have to be speaking a common language.

MileHigh

[MarkE]

There are at least several aspects of modern physics with respect to magnets that Tinman disagrees with.  And he thinks that he has good experimental evidence for his ideas. 

On the iron versus copper, pure iron has roughly  100:17X the resistivity of copper.  Whether Tinman has very pure iron wire or an allow we do not presently know.  But even with roughly 6X the resistivity of copper wire, the permeability is at least 1000X higher than the copper wire.  So even driving with about 2.4X voltage and getting about 0.4X current and 0.4X M, the flux density gradient near the poles is much higher.  Tinman is very visceral in his interpretaion of magnets.  If he sees higher mechanical force somewhere he has called that a stronger field.

[MileHigh]

This is going to be a time-out on this thread to address a completely different issue:

Captain Zero, can you see a nice lively discussion going on here?  Aren't we just discussing tech and bouncing ideas back and forth and having a spirited debate?

Is this the work of the evil cabal?  Are the Men in Black scurrying around in the background working to poison Timnan's mind?

This the stuff that you always ignore.  Just a friendly discussion with some strong views, all part of a healthy normal debate.  It's something very positive, people can read this stuff and try go get something out of it and improve their own skills.

But no, I and others are just "paid shills," here to "disrupt the creative process" according to you?  Between that crazy view of yours and your endless filthy potty-mouth scat-boy jackass talk, what an idiot you come across as.

Really, can you at least stop the infantile potty-mouth talk?  That would be a good first step.  The next step is to stop talking like some paranoid tragicomic character in some lousy B-grade Hollywood movie.  I am just so sick of it and I am willing to bet you that many other are too.

Stop the fucking ass-licking turd-boy talk, please!

MileHigh

[MarkE]

This is going to be a time-out on this thread to address a completely different issue:

Captain Zero, can you see a nice lively discussion going on here?  Aren't we just discussing tech and bouncing ideas back and forth and having a spirited debate?

Is this the work of the evil cabal?  Are the Men in Black scurrying around in the background working to poison Timnan's mind?

This the stuff that you always ignore.  Just a friendly discussion with some strong views, all part of a healthy normal debate.  It's something very positive, people can read this stuff and try go get something out of it and improve their own skills.

But no, I and others are just "paid shills," here to "disrupt the creative process" according to you?  Between that crazy view of yours and your endless filthy potty-mouth scat-boy jackass talk, what an idiot you come across as.

Really, can you at least stop the infantile potty-mouth talk?  That would be a good first step.  The next step is to stop talking like some paranoid tragicomic character in some lousy B-grade Hollywood movie.  I am just so sick of it and I am willing to bet you that many other are too.

Stop the fucking ass-licking turd-boy talk, please!

MileHigh

Please don't say Beetlejuice three times.