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Magnets repel more weakly than attract

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  Magnets repel more weakly than attract omnilobe@gmail.com - 2016-06-21 16:08 -0700
    Magnets repel more weakly than attract john <johnsefton288@gmail.com> - 2016-06-21 16:20 -0700
    Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-21 19:31 -0700
      Re: Magnets repel more weakly than attract omnilobe@gmail.com - 2016-06-21 21:02 -0700
    Re: Magnets repel more weakly than attract Sylvia Else <sylvia@not.at.this.address> - 2016-06-22 15:57 +1000
      Re: Magnets repel more weakly than attract omnilobe@gmail.com - 2016-06-22 08:28 -0700
        Re: Magnets repel more weakly than attract Sylvia Else <sylvia@not.at.this.address> - 2016-06-23 12:07 +1000
          Re: Magnets repel more weakly than attract benj <benj@nobody.net> - 2016-06-23 17:29 -0400
            Re: Magnets repel more weakly than attract Sylvia Else <sylvia@not.at.this.address> - 2016-06-24 10:10 +1000
              Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-24 08:44 -0700
            Re: Magnets repel more weakly than attract Timo <timo@physics.uq.edu.au> - 2016-06-24 15:05 -0700
            Re: Magnets repel more weakly than attract Timo <timo@physics.uq.edu.au> - 2016-06-24 03:36 -0700
            Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-23 16:42 -0700
            Re: Magnets repel more weakly than attract Timo <timo@physics.uq.edu.au> - 2016-06-24 17:56 -0700
          Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-23 15:32 -0700
        Re: Magnets repel more weakly than attract Helmut Wabnig <hwabnig@.- --- -.dotat> - 2016-06-23 07:20 +0200
      Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-22 11:47 -0700
        Re: Magnets repel more weakly than attract benj <benj@nobody.net> - 2016-06-22 16:17 -0400
          Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-22 15:45 -0700
    Re: Magnets repel more weakly than attract "Y.Porat" <y.y.porat@gmail.com> - 2016-06-23 02:32 -0700
    Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-24 08:41 -0700
    Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-23 15:30 -0700
    Re: Magnets repel more weakly than attract "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-06-23 16:41 -0700

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#586090 — Magnets repel more weakly than attract

I did not do the experiment. Do you expect that two similar magnets attract with a force F and repel with a force -0.9F at a distance of zero between the magnets?

The experiment is simple, but rarely mentioned. The "pull force" is measured for a magnet using a spring scale. The attraction force is measured and reported as F Newtons for one test. But the force when the magnets repel is not reported as "push force".

The lack of standardization of magnet specs might be because of the fear of being wrong in some common cases. The manufacturers should publish tables of magnet force versus Tesla flux density.

Proposed Theory : two equal permanent magnets attract stronger than they repel because of flux bundling. The attracting flux is bundled and the repelling flux is diverging. Two North poles facing each other must never let flux cross flux, so they diverge. A North facing a South magnetic pole does not cross flux lines, it completes flux lines, so a tightening of the flux bundle occurs where the two magnets touch. Any stray flux gets pulled closer to the attracting magnets. But repelling magnets have flux diverging into stray locations.

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#586091

Cool

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#586114

On Tuesday, June 21, 2016 at 4:09:02 PM UTC-7, omni...@gmail.com wrote:
> I did not do the experiment. Do you expect that two similar magnets attract with a force F and repel with a force -0.9F at a distance of zero between the magnets?
> 
> The experiment is simple, but rarely mentioned. The "pull force" is measured for a magnet using a spring scale. The attraction force is measured and reported as F Newtons for one test. But the force when the magnets repel is not reported as "push force".
> 
> The lack of standardization of magnet specs might be because of the fear of being wrong in some common cases. The manufacturers should publish tables of magnet force versus Tesla flux density.
> 
> Proposed Theory : two equal permanent magnets attract stronger than they repel because of flux bundling. The attracting flux is bundled and the repelling flux is diverging. Two North poles facing each other must never let flux cross flux, so they diverge. A North facing a South magnetic pole does not cross flux lines, it completes flux lines, so a tightening of the flux bundle occurs where the two magnets touch. Any stray flux gets pulled closer to the attracting magnets. But repelling magnets have flux diverging into stray locations.

How much stronger? It seems logical to me,but I never gave it a thought till now  TreBert

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#586121

On Tuesday, June 21, 2016 at 4:31:33 PM UTC-10, reber g=emc^2 wrote:
> On Tuesday, June 21, 2016 at 4:09:02 PM UTC-7, omni...@gmail.com wrote:
> > I did not do the experiment. Do you expect that two similar magnets attract with a force F and repel with a force -0.9F at a distance of zero between the magnets?
> > 
> > The experiment is simple, but rarely mentioned. The "pull force" is measured for a magnet using a spring scale. The attraction force is measured and reported as F Newtons for one test. But the force when the magnets repel is not reported as "push force".
> > 
> > The lack of standardization of magnet specs might be because of the fear of being wrong in some common cases. The manufacturers should publish tables of magnet force versus Tesla flux density.
> > 
> > Proposed Theory : two equal permanent magnets attract stronger than they repel because of flux bundling. The attracting flux is bundled and the repelling flux is diverging. Two North poles facing each other must never let flux cross flux, so they diverge. A North facing a South magnetic pole does not cross flux lines, it completes flux lines, so a tightening of the flux bundle occurs where the two magnets touch. Any stray flux gets pulled closer to the attracting magnets. But repelling magnets have flux diverging into stray locations.
> 
> How much stronger? It seems logical to me,but I never gave it a thought till now  TreBert

How much stronger is unknown. I even searched a web, where one guy said a company confirmed it is weaker to repel. Also, two magnets together by attraction will be stable for decades, and two other magnets stacked South to South will get 10% weaker in X days.

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#586128

On 22/06/2016 9:08 AM, omnilobe@gmail.com wrote:
> I did not do the experiment. Do you expect that two similar magnets
> attract with a force F and repel with a force -0.9F at a distance of
> zero between the magnets?
>
> The experiment is simple, but rarely mentioned. The "pull force" is
> measured for a magnet using a spring scale. The attraction force is
> measured and reported as F Newtons for one test. But the force when
> the magnets repel is not reported as "push force".
>
> The lack of standardization of magnet specs might be because of the
> fear of being wrong in some common cases. The manufacturers should
> publish tables of magnet force versus Tesla flux density.
>
> Proposed Theory : two equal permanent magnets attract stronger than
> they repel because of flux bundling. The attracting flux is bundled
> and the repelling flux is diverging. Two North poles facing each
> other must never let flux cross flux, so they diverge. A North facing
> a South magnetic pole does not cross flux lines, it completes flux
> lines, so a tightening of the flux bundle occurs where the two
> magnets touch. Any stray flux gets pulled closer to the attracting
> magnets. But repelling magnets have flux diverging into stray
> locations.
>

It's not as if flux is a real thing, it's just an indication of the 
direction and strength of the field. Clearly, flux lines cannot cross 
because that would mean that the field and strength at the point of 
intersection had more than one value - a physical impossibility.

The field at any point is just the sum the fields of the individual 
magnets at that point.

If you're seeing differences in attraction and repulsion, it's just 
because the field of each magnet affects the other magnet.

Sylvia.

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#586164

On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
"It's not as if flux is a real thing, it's just an indication of the direction and strength of the field. "

Flux is real. It is different from gravity and similar in ways. Flux penetrates rocks and lithium metal with real effectiveness.

"Clearly, flux lines cannot cross". 

A law is born. When matter cuts flux, a generator is possible. Matter has area called charge that cuts flux.

"If you're seeing differences in attraction and repulsion, it's just 
because the field of each magnet affects the other magnet. Sylvia."

I am imagining a weaker repulsion because no data is available to confirm the difference between magnets that repel or attract. Where are the numbers? Where is the formula? I bought a book on linear motors and actuators, but they are also trying to figure this out. It is complicated and it depends in shape, domains, and surroundings. Their formulas are not good enough to answer the questions of a 12 year old hobbyist. Magnets need more measurements and reports to satisfy people who expect better of science than the improvised rules of thumb.

Billions of dollars are wasted looking for black holes, dark matter, and magnetars, but on Earth, ordinary magnets are ignored. Even a basic repulsion fact is just because of a field that is never described mathematically in sufficient detail.

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#586259

On 23/06/2016 1:28 AM, omnilobe@gmail.com wrote:
> On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
> "It's not as if flux is a real thing, it's just an indication of the
> direction and strength of the field."
>
> Flux is real. It is different from gravity and similar in ways. Flux
> penetrates rocks and lithium metal with real effectiveness.
>
> "Clearly, flux lines cannot cross".
>
> A law is born. When matter cuts flux, a generator is possible. Matter
> has area called charge that cuts flux.
>
> "If you're seeing differences in attraction and repulsion, it's just
> because the field of each magnet affects the other magnet. Sylvia."
>
> I am imagining a weaker repulsion because no data is available to
> confirm the difference between magnets that repel or attract. Where
> are the numbers? Where is the formula? I bought a book on linear
> motors and actuators, but they are also trying to figure this out. It
> is complicated and it depends in shape, domains, and surroundings.
> Their formulas are not good enough to answer the questions of a 12
> year old hobbyist. Magnets need more measurements and reports to
> satisfy people who expect better of science than the improvised rules
> of thumb.
>
> Billions of dollars are wasted looking for black holes, dark matter,
> and magnetars, but on Earth, ordinary magnets are ignored. Even a
> basic repulsion fact is just because of a field that is never
> described mathematically in sufficient detail.
>

Consider how a magnet interacts with a non-magnetised piece of iron. The 
field of the magnet causes domains in the iron to orientate themselves 
according to the field. The result is that the magnet attracts the iron, 
which is temporarily magnetised.

Now consider two magnets. When orientated so that they attract, the 
field of each causes further alignment of the domains in the other, and 
that alignment reinforces the field, increasing the attraction.

Now orientate the magnets so that they repel. The field of each reduces 
the field that's orientating the domains in the other. Some of those 
domains lose orientation, reducing the total field. Net result - a lower 
repulsive force than there was previously an attractive force.

So there's nothing to see here. Move along.

Sylvia.

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#586351

On 6/22/2016 10:07 PM, Sylvia Else wrote:
> On 23/06/2016 1:28 AM, omnilobe@gmail.com wrote:
>> On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
>> "It's not as if flux is a real thing, it's just an indication of the
>> direction and strength of the field."
>>
>> Flux is real. It is different from gravity and similar in ways. Flux
>> penetrates rocks and lithium metal with real effectiveness.
>>
>> "Clearly, flux lines cannot cross".
>>
>> A law is born. When matter cuts flux, a generator is possible. Matter
>> has area called charge that cuts flux.
>>
>> "If you're seeing differences in attraction and repulsion, it's just
>> because the field of each magnet affects the other magnet. Sylvia."
>>
>> I am imagining a weaker repulsion because no data is available to
>> confirm the difference between magnets that repel or attract. Where
>> are the numbers? Where is the formula? I bought a book on linear
>> motors and actuators, but they are also trying to figure this out. It
>> is complicated and it depends in shape, domains, and surroundings.
>> Their formulas are not good enough to answer the questions of a 12
>> year old hobbyist. Magnets need more measurements and reports to
>> satisfy people who expect better of science than the improvised rules
>> of thumb.
>>
>> Billions of dollars are wasted looking for black holes, dark matter,
>> and magnetars, but on Earth, ordinary magnets are ignored. Even a
>> basic repulsion fact is just because of a field that is never
>> described mathematically in sufficient detail.
>>
>
> Consider how a magnet interacts with a non-magnetised piece of iron. The
> field of the magnet causes domains in the iron to orientate themselves
> according to the field. The result is that the magnet attracts the iron,
> which is temporarily magnetised.
>
> Now consider two magnets. When orientated so that they attract, the
> field of each causes further alignment of the domains in the other, and
> that alignment reinforces the field, increasing the attraction.
>
> Now orientate the magnets so that they repel. The field of each reduces
> the field that's orientating the domains in the other. Some of those
> domains lose orientation, reducing the total field. Net result - a lower
> repulsive force than there was previously an attractive force.
>
> So there's nothing to see here. Move along.
>
> Sylvia.

Great theory "Sylvia" but you don't have much to back it up. You know 
they are called permanent magnets because the domains DO NOT "lose 
orientation" unlike iron. I'm sure one might propose a slight spring 
like deflection of domains which snap back once field is gone, but I 
doubt this effect is significant. In fact, I doubt there are very few 
credible measurements of ANY of this including the alleged difference 
between attraction and repulsion.

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#586361

On 24/06/2016 7:29 AM, benj wrote:
> On 6/22/2016 10:07 PM, Sylvia Else wrote:
>> On 23/06/2016 1:28 AM, omnilobe@gmail.com wrote:
>>> On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
>>> "It's not as if flux is a real thing, it's just an indication of the
>>> direction and strength of the field."
>>>
>>> Flux is real. It is different from gravity and similar in ways. Flux
>>> penetrates rocks and lithium metal with real effectiveness.
>>>
>>> "Clearly, flux lines cannot cross".
>>>
>>> A law is born. When matter cuts flux, a generator is possible. Matter
>>> has area called charge that cuts flux.
>>>
>>> "If you're seeing differences in attraction and repulsion, it's just
>>> because the field of each magnet affects the other magnet. Sylvia."
>>>
>>> I am imagining a weaker repulsion because no data is available to
>>> confirm the difference between magnets that repel or attract. Where
>>> are the numbers? Where is the formula? I bought a book on linear
>>> motors and actuators, but they are also trying to figure this out. It
>>> is complicated and it depends in shape, domains, and surroundings.
>>> Their formulas are not good enough to answer the questions of a 12
>>> year old hobbyist. Magnets need more measurements and reports to
>>> satisfy people who expect better of science than the improvised rules
>>> of thumb.
>>>
>>> Billions of dollars are wasted looking for black holes, dark matter,
>>> and magnetars, but on Earth, ordinary magnets are ignored. Even a
>>> basic repulsion fact is just because of a field that is never
>>> described mathematically in sufficient detail.
>>>
>>
>> Consider how a magnet interacts with a non-magnetised piece of iron. The
>> field of the magnet causes domains in the iron to orientate themselves
>> according to the field. The result is that the magnet attracts the iron,
>> which is temporarily magnetised.
>>
>> Now consider two magnets. When orientated so that they attract, the
>> field of each causes further alignment of the domains in the other, and
>> that alignment reinforces the field, increasing the attraction.
>>
>> Now orientate the magnets so that they repel. The field of each reduces
>> the field that's orientating the domains in the other. Some of those
>> domains lose orientation, reducing the total field. Net result - a lower
>> repulsive force than there was previously an attractive force.
>>
>> So there's nothing to see here. Move along.
>>
>> Sylvia.
>
> Great theory "Sylvia" but you don't have much to back it up. You know
> they are called permanent magnets because the domains DO NOT "lose
> orientation" unlike iron. I'm sure one might propose a slight spring
> like deflection of domains which snap back once field is gone, but I
> doubt this effect is significant. In fact, I doubt there are very few
> credible measurements of ANY of this including the alleged difference
> between attraction and repulsion.
>
>

The fact that they're permanent magnets only means that some of the 
domains have persistent orientations. It doesn't mean that every domain 
in the magnet does.

Sylvia.

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#586442

On Thursday, June 23, 2016 at 5:11:04 PM UTC-7, Sylvia Else wrote:
> On 24/06/2016 7:29 AM, benj wrote:
> > On 6/22/2016 10:07 PM, Sylvia Else wrote:
> >> On 23/06/2016 1:28 AM, omnilobe@gmail.com wrote:
> >>> On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
> >>> "It's not as if flux is a real thing, it's just an indication of the
> >>> direction and strength of the field."
> >>>
> >>> Flux is real. It is different from gravity and similar in ways. Flux
> >>> penetrates rocks and lithium metal with real effectiveness.
> >>>
> >>> "Clearly, flux lines cannot cross".    I have an ifdea all poles do line up to make a magnet,and none left out. Trebert
> >>>
> >>> A law is born. When matter cuts flux, a generator is possible. Matter
> >>> has area called charge that cuts flux.
> >>>
> >>> "If you're seeing differences in attraction and repulsion, it's just
> >>> because the field of each magnet affects the other magnet. Sylvia."
> >>>
> >>> I am imagining a weaker repulsion because no data is available to
> >>> confirm the difference between magnets that repel or attract. Where
> >>> are the numbers? Where is the formula? I bought a book on linear
> >>> motors and actuators, but they are also trying to figure this out. It
> >>> is complicated and it depends in shape, domains, and surroundings.
> >>> Their formulas are not good enough to answer the questions of a 12
> >>> year old hobbyist. Magnets need more measurements and reports to
> >>> satisfy people who expect better of science than the improvised rules
> >>> of thumb.
> >>>
> >>> Billions of dollars are wasted looking for black holes, dark matter,
> >>> and magnetars, but on Earth, ordinary magnets are ignored. Even a
> >>> basic repulsion fact is just because of a field that is never
> >>> described mathematically in sufficient detail.
> >>>
> >>
> >> Consider how a magnet interacts with a non-magnetised piece of iron. The
> >> field of the magnet causes domains in the iron to orientate themselves
> >> according to the field. The result is that the magnet attracts the iron,
> >> which is temporarily magnetised.
> >>
> >> Now consider two magnets. When orientated so that they attract, the
> >> field of each causes further alignment of the domains in the other, and
> >> that alignment reinforces the field, increasing the attraction.
> >>
> >> Now orientate the magnets so that they repel. The field of each reduces
> >> the field that's orientating the domains in the other. Some of those
> >> domains lose orientation, reducing the total field. Net result - a lower
> >> repulsive force than there was previously an attractive force.
> >>
> >> So there's nothing to see here. Move along.
> >>
> >> Sylvia.
> >
> > Great theory "Sylvia" but you don't have much to back it up. You know
> > they are called permanent magnets because the domains DO NOT "lose
> > orientation" unlike iron. I'm sure one might propose a slight spring
> > like deflection of domains which snap back once field is gone, but I
> > doubt this effect is significant. In fact, I doubt there are very few
> > credible measurements of ANY of this including the alleged difference
> > between attraction and repulsion.
> >
> >
> 
> The fact that they're permanent magnets only means that some of the 
> domains have persistent orientations. It doesn't mean that every domain 
> in the magnet does.
> 
> Sylvia.

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#586453

On Friday, June 24, 2016 at 7:30:06 AM UTC+10, benj wrote:
> On 6/22/2016 10:07 PM, Sylvia Else wrote:
> >
> > Now orientate the magnets so that they repel. The field of each reduces
> > the field that's orientating the domains in the other. Some of those
> > domains lose orientation, reducing the total field. Net result - a lower
> > repulsive force than there was previously an attractive force.
> >
> > So there's nothing to see here. Move along.
> 
> Great theory "Sylvia" but you don't have much to back it up. You know 
> they are called permanent magnets because the domains DO NOT "lose 
> orientation" unlike iron. I'm sure one might propose a slight spring 
> like deflection of domains which snap back once field is gone, but I 
> doubt this effect is significant. In fact, I doubt there are very few 
> credible measurements of ANY of this including the alleged difference 
> between attraction and repulsion.

It's easy to find measurements:
https://www.supermagnete.de/eng/faq/Is-the-attraction-between-magnets-as-high-as-the-repulsion
You could even do as scientists do when they can't find reliable measurements: measure it yourself. Measurement trumps speculation.

The electrostatic case is nice. Since everybody knows that like charges repel, attracting a like-charged object can be a mind-challenging demo. (It isn't the same as the magnetic case, since it's an induced dipole competing with a monopole, rather than an induced dipole reinforcing or reducing a permanent dipole.)

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#586460

On Friday, June 24, 2016 at 7:30:06 AM UTC+10, benj wrote:
> On 6/22/2016 10:07 PM, Sylvia Else wrote:
> >
> > Now consider two magnets. When orientated so that they attract, the
> > field of each causes further alignment of the domains in the other, and
> > that alignment reinforces the field, increasing the attraction.
> >
> > Now orientate the magnets so that they repel. The field of each reduces
> > the field that's orientating the domains in the other. Some of those
> > domains lose orientation, reducing the total field. Net result - a lower
> > repulsive force than there was previously an attractive force.
> >
> > So there's nothing to see here. Move along.
> 
> Great theory "Sylvia" but you don't have much to back it up. You know 
> they are called permanent magnets because the domains DO NOT "lose 
> orientation" unlike iron. I'm sure one might propose a slight spring 
> like deflection of domains which snap back once field is gone, but I 
> doubt this effect is significant. In fact, I doubt there are very few 
> credible measurements of ANY of this including the alleged difference 
> between attraction and repulsion.

It's easy enough to find measurements online:
https://www.supermagnete.de/eng/faq/Is-the-attraction-between-magnets-as-high-as-the-repulsion

You could also do it the old-fashioned way: measure it yourself. Measurement trumps speculation.

The electrostatic version can be fun, too. Since everybody knows that a positively charged body will repel a positively charged body, a demonstration showing attraction instead has some impact. (It isn't quite the same as the magnet version - in the electrostatic version, it's the induced dipole competing with the monopole, rather than the induced dipole reinforcing or reducing the permanent dipole.)

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#586471

On Thursday, June 23, 2016 at 2:30:06 PM UTC-7, benj wrote:
> On 6/22/2016 10:07 PM, Sylvia Else wrote:
> > On 23/06/2016 1:28 AM, omnilobe@gmail.com wrote:
> >> On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
> >> "It's not as if flux is a real thing, it's just an indication of the
> >> direction and strength of the field."
> >>
> >> Flux is real. It is different from gravity and similar in ways. Flux
> >> penetrates rocks and lithium metal with real effectiveness.
> >>
> >> "Clearly, flux lines cannot cross".
> >>
> >> A law is born. When matter cuts flux, a generator is possible. Matter
> >> has area called charge that cuts flux.
> >>
> >> "If you're seeing differences in attraction and repulsion, it's just
> >> because the field of each magnet affects the other magnet. Sylvia."
> >>
> >> I am imagining a weaker repulsion because no data is available to
> >> confirm the difference between magnets that repel or attract. Where
> >> are the numbers? Where is the formula? I bought a book on linear
> >> motors and actuators, but they are also trying to figure this out. It
> >> is complicated and it depends in shape, domains, and surroundings.
> >> Their formulas are not good enough to answer the questions of a 12
> >> year old hobbyist. Magnets need more measurements and reports to
> >> satisfy people who expect better of science than the improvised rules
> >> of thumb.
> >>
> >> Billions of dollars are wasted looking for black holes, dark matter,
> >> and magnetars, but on Earth, ordinary magnets are ignored. Even a
> >> basic repulsion fact is just because of a field that is never
> >> described mathematically in sufficient detail.
> >>
> >
> > Consider how a magnet interacts with a non-magnetised piece of iron. The
> > field of the magnet causes domains in the iron to orientate themselves
> > according to the field. The result is that the magnet attracts the iron,
> > which is temporarily magnetised.
> >
> > Now consider two magnets. When orientated so that they attract, the
> > field of each causes further alignment of the domains in the other, and
> > that alignment reinforces the field, increasing the attraction.
> >
> > Now orientate the magnets so that they repel. The field of each reduces
> > the field that's orientating the domains in the other. Some of those
> > domains lose orientation, reducing the total field. Net result - a lower
> > repulsive force than there was previously an attractive force.
> >
> > So there's nothing to see here. Move along.
> >
> > Sylvia.
> 
> Great theory "Sylvia" but you don't have much to back it up. You know 
> they are called permanent magnets because the domains DO NOT "lose 
> orientation" unlike iron. I'm sure one might propose a slight spring 
> like deflection of domains which snap back once field is gone, but I 
> doubt this effect is significant. In fact, I doubt there are very few 
> credible measurements of ANY of this including the alleged difference 
> between attraction and repulsion.

[toc] | [prev] | [next] | [standalone]

#586487

On Friday, June 24, 2016 at 7:30:06 AM UTC+10, benj wrote:
> On 6/22/2016 10:07 PM, Sylvia Else wrote:
> >
> > Now consider two magnets. When orientated so that they attract, the
> > field of each causes further alignment of the domains in the other, and
> > that alignment reinforces the field, increasing the attraction.
> >
> > Now orientate the magnets so that they repel. The field of each reduces
> > the field that's orientating the domains in the other. Some of those
> > domains lose orientation, reducing the total field. Net result - a lower
> > repulsive force than there was previously an attractive force.
> >
> > So there's nothing to see here. Move along.
> 
> Great theory "Sylvia" but you don't have much to back it up. You know 
> they are called permanent magnets because the domains DO NOT "lose 
> orientation" unlike iron. I'm sure one might propose a slight spring 
> like deflection of domains which snap back once field is gone, but I 
> doubt this effect is significant. In fact, I doubt there are very few 
> credible measurements of ANY of this including the alleged difference 
> between attraction and repulsion.

So, if you feel there aren't credible measurements, why not do as scientists do, and measure. Measurement trumps idle speculation!

However, it seems that it's easy enough to find credible measurements:
https://www.supermagnete.de/eng/faq/Is-the-attraction-between-magnets-as-high-as-the-repulsion

The electrostatic equivalent is fun. Since everybody knows that like charges repel, attracting a like-charged object provides a nice puzzle. (It isn't the same as the magnet case, since it's an induced dipole competing with a monopole, rather than an induced dipole reinforcing or reducing a permanent dipole.)

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#586443

On Wednesday, June 22, 2016 at 7:07:14 PM UTC-7, Sylvia Else wrote:
> On 23/06/2016 1:28 AM, omnilobe@gmail.com wrote:
> > On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
> > "It's not as if flux is a real thing, it's just an indication of the
> > direction and strength of the field."
> >
> > Flux is real. It is different from gravity and similar in ways. Flux
> > penetrates rocks and lithium metal with real effectiveness.
> >
> > "Clearly, flux lines cannot cross".
> >
> > A law is born. When matter cuts flux, a generator is possible. Matter
> > has area called charge that cuts flux.
> >
> > "If you're seeing differences in attraction and repulsion, it's just
> > because the field of each magnet affects the other magnet. Sylvia."
> >
> > I am imagining a weaker repulsion because no data is available to
> > confirm the difference between magnets that repel or attract. Where
> > are the numbers? Where is the formula? I bought a book on linear
> > motors and actuators, but they are also trying to figure this out. It
> > is complicated and it depends in shape, domains, and surroundings.
> > Their formulas are not good enough to answer the questions of a 12
> > year old hobbyist. Magnets need more measurements and reports to
> > satisfy people who expect better of science than the improvised rules
> > of thumb.
> >
> > Billions of dollars are wasted looking for black holes, dark matter,
> > and magnetars, but on Earth, ordinary magnets are ignored. Even a
> > basic repulsion fact is just because of a field that is never
> > described mathematically in sufficient detail.
> >
> 
> Consider how a magnet interacts with a non-magnetised piece of iron. The 
> field of the magnet causes domains in the iron to orientate themselves 
> according to the field. The result is that the magnet attracts the iron, 
> which is temporarily magnetised.
> 
> Now consider two magnets. When orientated so that they attract, the 
> field of each causes further alignment of the domains in the other, and 
> that alignment reinforces the field, increasing the attraction.
> 
> Now orientate the magnets so that they repel. The field of each reduces 
> the field that's orientating the domains in the other. Some of those 
> domains lose orientation, reducing the total field. Net result - a lower 
> repulsive force than there was previously an attractive force.
> 
> So there's nothing to see here. Move along.
> 
> Sylvia.

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#586274

On Wed, 22 Jun 2016 08:28:24 -0700 (PDT), omnilobe@gmail.com wrote:

>On Tuesday, June 21, 2016 at 7:57:51 PM UTC-10, Sylvia Else wrote:
>"It's not as if flux is a real thing, it's just an indication of the direction and strength of the field. "
>
>Flux is real. It is different from gravity and similar in ways. Flux penetrates rocks and lithium metal with real effectiveness.
>
>"Clearly, flux lines cannot cross". 
>
>A law is born. When matter cuts flux, a generator is possible. Matter has area called charge that cuts flux.
>
>"If you're seeing differences in attraction and repulsion, it's just 
>because the field of each magnet affects the other magnet. Sylvia."
>
>I am imagining a weaker repulsion because no data is available to confirm the difference between magnets that repel or attract. Where are the numbers? Where is the formula? I bought a book on linear motors and actuators, but they are also trying to figure this out. It is complicated and it depends in shape, domains, and surroundings. Their formulas are not good enough to answer the questions of a 12 year old hobbyist. Magnets need more measurements and reports to satisfy people who expect better of science than the improvised rules of thumb.
>
>Billions of dollars are wasted looking for black holes, dark matter, and magnetars, but on Earth, ordinary magnets are ignored. Even a basic repulsion fact is just because of a field that is never described mathematically in sufficient detail.

This is my all-time favorite.
A wonderful example how a false law can be useful:
>A law is born. When matter cuts flux, a generator is possible.


This flux-lines-cutting theorem is wrong physics.
That moving wire cutting "flux lines" has helped a lot
from the beginning of electricity until now
and is still used in teaching basic electromagnetism.

Alas, the image is wrong.
Can you think why?

(Hint: wires always form a loop).

w.

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#586202

On Tuesday, June 21, 2016 at 10:57:51 PM UTC-7, Sylvia Else wrote:
> On 22/06/2016 9:08 AM, omnilobe@gmail.com wrote:
> > I did not do the experiment. Do you expect that two similar magnets
> > attract with a force F and repel with a force -0.9F at a distance of
> > zero between the magnets?
> >
> > The experiment is simple, but rarely mentioned. The "pull force" is
> > measured for a magnet using a spring scale. The attraction force is
> > measured and reported as F Newtons for one test. But the force when
> > the magnets repel is not reported as "push force".
> >
> > The lack of standardization of magnet specs might be because of the
> > fear of being wrong in some common cases. The manufacturers should
> > publish tables of magnet force versus Tesla flux density.
> >
> > Proposed Theory : two equal permanent magnets attract stronger than
> > they repel because of flux bundling. The attracting flux is bundled
> > and the repelling flux is diverging. Two North poles facing each
> > other must never let flux cross flux, so they diverge. A North facing
> > a South magnetic pole does not cross flux lines, it completes flux
> > lines, so a tightening of the flux bundle occurs where the two
> > magnets touch. Any stray flux gets pulled closer to the attracting
> > magnets. But repelling magnets have flux diverging into stray
> > locations.
> >
> 
> It's not as if flux is a real thing, it's just an indication of the 
> direction and strength of the field. Clearly, flux lines cannot cross 
> because that would mean that the field and strength at the point of 
> intersection had more than one value - a physical impossibility.
> 
> The field at any point is just the sum the fields of the individual 
> magnets at that point.
> 
> If you're seeing differences in attraction and repulsion, it's just 
> because the field of each magnet affects the other magnet.
> 
> Sylvia.

Magnets best to store with their N and S poles in line with earth's magnetic field.They stay strong. Best not to drop them,or heat them.(Curie effect)  TreBert

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#586213

On 6/22/2016 2:47 PM, reber g=emc^2 wrote:
> On Tuesday, June 21, 2016 at 10:57:51 PM UTC-7, Sylvia Else wrote:
>> On 22/06/2016 9:08 AM, omnilobe@gmail.com wrote:
>>> I did not do the experiment. Do you expect that two similar magnets
>>> attract with a force F and repel with a force -0.9F at a distance of
>>> zero between the magnets?
>>>
>>> The experiment is simple, but rarely mentioned. The "pull force" is
>>> measured for a magnet using a spring scale. The attraction force is
>>> measured and reported as F Newtons for one test. But the force when
>>> the magnets repel is not reported as "push force".
>>>
>>> The lack of standardization of magnet specs might be because of the
>>> fear of being wrong in some common cases. The manufacturers should
>>> publish tables of magnet force versus Tesla flux density.
>>>
>>> Proposed Theory : two equal permanent magnets attract stronger than
>>> they repel because of flux bundling. The attracting flux is bundled
>>> and the repelling flux is diverging. Two North poles facing each
>>> other must never let flux cross flux, so they diverge. A North facing
>>> a South magnetic pole does not cross flux lines, it completes flux
>>> lines, so a tightening of the flux bundle occurs where the two
>>> magnets touch. Any stray flux gets pulled closer to the attracting
>>> magnets. But repelling magnets have flux diverging into stray
>>> locations.
>>>
>>
>> It's not as if flux is a real thing, it's just an indication of the
>> direction and strength of the field. Clearly, flux lines cannot cross
>> because that would mean that the field and strength at the point of
>> intersection had more than one value - a physical impossibility.
>>
>> The field at any point is just the sum the fields of the individual
>> magnets at that point.
>>
>> If you're seeing differences in attraction and repulsion, it's just
>> because the field of each magnet affects the other magnet.
>>
>> Sylvia.
>
> Magnets best to store with their N and S poles in line with earth's magnetic field.They stay strong. Best not to drop them,or heat them.(Curie effect)  TreBert
>
No problem Herb. HVAC (who also knows how everything works told me that 
if you hang magnets up by strings round their centers they they will 
always store in alignment and stay strong!

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#586239

On Wednesday, June 22, 2016 at 1:17:56 PM UTC-7, benj wrote:
> On 6/22/2016 2:47 PM, reber g=emc^2 wrote:
> > On Tuesday, June 21, 2016 at 10:57:51 PM UTC-7, Sylvia Else wrote:
> >> On 22/06/2016 9:08 AM, omnilobe@gmail.com wrote:
> >>> I did not do the experiment. Do you expect that two similar magnets
> >>> attract with a force F and repel with a force -0.9F at a distance of
> >>> zero between the magnets?
> >>>
> >>> The experiment is simple, but rarely mentioned. The "pull force" is
> >>> measured for a magnet using a spring scale. The attraction force is
> >>> measured and reported as F Newtons for one test. But the force when
> >>> the magnets repel is not reported as "push force".
> >>>
> >>> The lack of standardization of magnet specs might be because of the
> >>> fear of being wrong in some common cases. The manufacturers should
> >>> publish tables of magnet force versus Tesla flux density.
> >>>
> >>> Proposed Theory : two equal permanent magnets attract stronger than
> >>> they repel because of flux bundling. The attracting flux is bundled
> >>> and the repelling flux is diverging. Two North poles facing each
> >>> other must never let flux cross flux, so they diverge. A North facing
> >>> a South magnetic pole does not cross flux lines, it completes flux
> >>> lines, so a tightening of the flux bundle occurs where the two
> >>> magnets touch. Any stray flux gets pulled closer to the attracting
> >>> magnets. But repelling magnets have flux diverging into stray
> >>> locations.
> >>>
> >>
> >> It's not as if flux is a real thing, it's just an indication of the
> >> direction and strength of the field. Clearly, flux lines cannot cross
> >> because that would mean that the field and strength at the point of
> >> intersection had more than one value - a physical impossibility.
> >>
> >> The field at any point is just the sum the fields of the individual
> >> magnets at that point.
> >>
> >> If you're seeing differences in attraction and repulsion, it's just
> >> because the field of each magnet affects the other magnet.
> >>
> >> Sylvia.
> >
> > Magnets best to store with their N and S poles in line with earth's magnetic field.They stay strong. Best not to drop them,or heat them.(Curie effect)  TreBert
> >
> No problem Herb. HVAC (who also knows how everything works told me that 
> if you hang magnets up by strings round their centers they they will 
> always store in alignment and stay strong!

Float the magnet.Build the iron boat as a magnet and it will steer itself.Planes use gyro-compasses TreBert

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#586293

On Wednesday, June 22, 2016 at 2:09:02 AM UTC+3, omni...@gmail.com wrote:
> I did not do the experiment. Do you expect that two similar magnets attract with a force F and repel with a force -0.9F at a distance of zero between the magnets?
> 
> The experiment is simple, but rarely mentioned. The "pull force" is measured for a magnet using a spring scale. The attraction force is measured and reported as F Newtons for one test. But the force when the magnets repel is not reported as "push force".
> 
> The lack of standardization of magnet specs might be because of the fear of being wrong in some common cases. The manufacturers should publish tables of magnet force versus Tesla flux density.
> 
> Proposed Theory : two equal permanent magnets attract stronger than they repel because of flux bundling. The attracting flux is bundled and the repelling flux is diverging. Two North poles facing each other must never let flux cross flux, so they diverge. A North facing a South magnetic pole does not cross flux lines, it completes flux lines, so a tightening of the flux bundle occurs where the two magnets touch. Any stray flux gets pulled closer to the attracting magnets. But repelling magnets have flux diverging into stray locations.
===========================
see the Y Circlon mechanism
and you will get a hint why !!!

TIA
Y.Porat
=======================================

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