Back to Basics: What’s the deal with Magnets?

I consider myself a fairly sharp guy. I’ve made a living off of being a scientist for over 20 years now, and I have at least a passing knowledge of most scientific fields outside my area. But I feel like I should be able to do something other than babble incoherently when asked about magnets. They baffle me – there, I said it. So what do I do about it? Write a Hackaday post, naturally – chances are I’m not the only one with cryptomagnetonescience, even if I just made that term up. Maybe if we walk through the basics together, it’ll do us both some good understanding this fundamental and mysterious force of nature.

For this article, I’m mostly interested in permanent magnets. There’s something primal and universal about playing with permanent magnets, and feeling that invisible force field holding apart two magnets with the same poles facing each other is compelling in a way that few other science experiences are – except for maybe getting the same two magnets to stick to each other through the web between your thumb and forefinger. But what makes these two inert discs or balls or horseshoes act like that? Where does the seemingly inexhaustible energy to repel and attract come from? How do permanent magnets work?

Hitting the Books

My first stop on this journey was to go to the bookshelf and find an old physics book. I found the one I used in my undergrad days, Serway’s Physics for Scientists and Engineers. As fascinating as the book was, it didn’t help. A quarter century has passed since I cracked that very dusty book, and all I learned from it is that you can’t go back to your college days.

So next I looked around the web for some answers. At the end of the day, no matter whom you talk to about magnets and no matter how many words are stuffed into the explanation, the honest answer to how magnets work is, “We just don’t know.” We know a lot of things about magnetism – that it’s a property of space, for instance, and that the force field of magnets is composed of photons. But knowing that you can only explain permanent magnets in terms of quantum mechanics isn’t terribly helpful in my efforts to stop the hand waving. Time to turn to YouTube.

magnet-electron-shell
Orbitals in Iron. Source: HowStuffWorks

I dialed up a MinutePhysics video on magnets, and I found it really helpful. My main takeaway from the segment was that permanent magnets are best understood as really small electromagnets. It seems ironic that to explain a magnet with only one part we need to think in terms of a magnet made from wire coiled around a core and attached to a source of electricity, but there it is.

A basic fact of nature is that charged particles have intrinsic magnetic moments, which basically means they’re really small magnets. Electrons and protons are charged particles, so all matter is made of tiny magnets. It turns out that the protons are really weak, so the nucleus isn’t really invited to the magnet party being run by the electrons. This is convenient because we only have to look at the electrons, but also infuriating because we have to deal with the whole concept of electron shells. I’m not going to relive that hellish little section of Chemistry 101 except to say that in atoms with a filled shell, the magnetic field generated by any moving electron is going to be cancelled out by another electron in the same shell moving in the opposite direction. Also, filled shells have electrons in pairs, but their intrinsic moments are opposite of each other, and they also cancel each other out. So, no net magnetic field from atoms with filled shells.

periodic table
Periodic table of magnets. Source: MinutePhysics

But, in an atom with a half-filled shell, the electrons are unpaired, and their intrinsic moments are the same polarity. All those tiny magnets add up, and you’ve got yourself a magnet. And, because of the half-filled shells thing, it’s easy to spot which elements are likely to be magnetic on your periodic table. Half-filled shells occur near the middle of the f-block (the actinides and lanthanides) and the d-block (the metals). Notice that the top row of the d-block has all the “classic” magnetic elements – cobalt, manganese, chromium, nickel and the king of them all, iron. Ever heard of Alnico? It’s iron alloyed with aluminum, nickel and cobalt, and it’s used to make permanent magnets because it has high coercivity, which means that once it’s magnetized, it stays that way.

How to Make a Magnet

So how exactly are permanent magnets made? There are a lot of methods, most of which are basically some sort of metal manufacturing process, like casting, machining, or sintering. Most magnets undergo multiple operations, especially the super-strong rare-earth magnets, which also require extra protective plating with nickel to prevent corrosion. As an aside, the nickel plating stands up remarkably well after a two-day tour of the human digestive tract. Source: I’m a dad.

meters
Making magnets: 3 volts at 6000 amps! Source: How It’s Made

Once the metalwork is complete, the magnet still needs to be magnetized. There are a number of ways to accomplish this, but it basically seems to involve dumping a ridiculous number of electrons into a coil near the baby magnets and inducing a huge magnetic field that aligns the magnetic domains permanently. Notice the ammeter in this “How It’s Made” video; at the 3:53 mark, it’s reading 6,000 amps!

There’s another way to make a magnet that doesn’t involve banks of supercapacitors. In fact, blacksmiths have known for centuries that beating on hot metal can make it magnetic. When a ferromagnetic metal is heated past its Curie temperature, it loses its magnetic properties – see this video for a neat demonstration. Once past that temperature – about 1400°F for iron, or a light cherry red – the magnetic domains can be re-aligned by pounding on the metal while it’s oriented within a magnetic field, like the Earth’s. Better results can be achieved with a stronger magnetic field – for all it does to protect us from cosmic radiation, the Earth’s magnetic field is really kind of weak.

So in the final analysis, a permanent magnet is really just a device that captures a little bit of the magnetic field of another, stronger magnet. In other words, if you want to magnetize something, you need to move electrons. There’s no separating electricity and magnetism – they’re two sides of the same coin.

I’m glad I poked my head down the quantum rabbit hole that is magnetism. I’m nowhere near a complete understanding of how permanent magnets work, but I’m a little closer to it. Maybe I can stop the hand waving now and sound a little more authoritative on the subject.

82 thoughts on “Back to Basics: What’s the deal with Magnets?

    1. Wow… I love this for so many reasons. I like his standoffishness to the question at first. Then you get what seems like a really deeply-thought answer on how we can never know “why” about something to which we don’t have intuitive background knowledge.

      Great clip, thanks for sharing!

    2. TLDR: science postulates dogmatic axioms, and the merits of a set of axioms (and the known theorems that follow) are assessed on its predictive power balanced with conciseness (minimal set of axioms).

      This clip is linked very often, and I really enjoyed seeing it the first time around, but from the second time on I realized I mostly liked it for its entertainment value. In my opinion the stranger question is why is there dissipation on the “macroscopic” scale, but not on the “microscopic” scale? Without dissipation, i.e. just Lorentz force and Maxwell equations, 2 attractive charges rotating about each other also result in a magnetic field with a dipole… No quantum mechanics needed to clarify that.

      1. “Without dissipation, i.e. just Lorentz force and Maxwell equations, 2 attractive charges rotating about each other also result in a magnetic field with a dipole…”

        Opposing charges rotating about a common center will create opposite magnetic fields and cancel each other out.

      2. >> “science postulates dogmatic axioms”

        Not at all. Science postulates -provisional- axioms.
        Either through a miscommunication of your own, or misunderstanding of Feynmans’ words your comment has fallen terribly short of the mark.
        In the case of his explanation for magnetism, he’s not saying we should accept it as a fact of the world and never question it (a ‘dogma’ as you called it) but that his own understanding of magnetism, and it’s fundamental forces, is lacking the detail to explain it to the interviewer/Joe Public in a manner that would be easily understood. If you wanted to sit through a semester of advanced physics and mathematics I’m sure he could have filled chalkboards with the ‘why’s’ of magnetism.

        The rub here, is that axioms used by science are discarded or modified when their predictive value is lost. They are nothing like a ‘dogma’.

  1. according to this article, the shiny shell on a rare earth magnet is nickel. at home I have a couple of HDD magnets where the coating has flaked off. Do I need to worry about health problems being exposed to “uncovered” rare earth magnets or is the coating only there to prevent corrosion and to make the magnet look like more than a slab of rock?

    1. From what I read, unplated rare-earth magnets corrode very quickly and lose their magnetism as a result. I don’t think the plating is there to protect you from the metals. YMMV, of course, but anecdotally, I can report that rare-earth magnets do no apparent harm to larval humans when just passing through. As long it’s only one magnet – multiple magnets tend to find each other in the guts and stick together, sometimes through loops of bowel and cause perforations and peritonitis.

        1. Larval humans = babies.

          I have a rare-earth magnet which broke in half as a result of impact. I covered the exposed areas with Scotch tape, mainly to prevent contact with the sharp edge. Corrosion of the surface appeared quickly, but then didn’t progress much over the next 20 or so years. I think a coat of paint would be sufficient protection in cases where the nickel plating has flaked away. That particular magnet was in fact originally painted rather than plated, with what appears to be epoxy.

      1. There were some magnetic building toys where the magnets weren’t secured well enough and some kids were able to either pry them out or they fell out. Since their parents were either not observant enough or failed to teach them not to put stuff in their mouths that wasn’t food or an eating utensil carrying food, the kids swallowed one or more magnets, then some time later swallowed more.

        Same story with those “buckyball” magnetic spheres. Most likely came with warnings to keep away from children prone to putting non-food stuff in their mouths, that parents ignored.

        If two or more are swallowed together, they’ll stick together in the stomach and pass without a problem. Or if they are swallowed with enough time between, no problem. The problem happens when the magnets end up in the small intestine in different locations but close enough together to attract.

        1. I love the parental deficit model you present. Of course it’s ludicrous as parents can’t supervise 100% of the time. Like other humans, parents need to do things like defecate and sleep and these things take them away from their supervisory role.

          The funny part is that it shows that you don’t have a clue about parenting and yet, ironically, you present your assessment forth as though professional.

          While I don’t mean any offence to you, you should be aware that commenting about parenting (as a non-parent) makes you look like a fool.

          Seriously, if we left parenting to non-parents then very few children would survive to adulthood, let alone become contributing members of our society.

          1. Galane has a somewhat valid point. Nobody is a perfect parent but there is a very large gray area about what constitutes good parenting and bad parenting.

            A large part of it is access to education about children. Not in a formal sense but in an informal sense as a family. The U.S. is seemingly dominated by nuclear, broken and mixed families. The hard earned knowledge of the previous generations is easily lost with each new generation because the U.S., as a whole, don’t tend to refer to elders for information.

            This is further exasperated by media (television, books and internet) rife with misleading and dangerous information. Nor does it help seeing a parent posting on Facebook with their smartphone while their child is sticking a paperclip in an electric outlet.

            On the flip side, I can come up with an enormous list of parents who have no business being parents. Just look in the news any day of the week.

            Might be true that non-parents should butt out, but I can point out far too many parents who have no business breeding stupidity.

            My qualification are my three creature creations that eat my food and sleep iny house and bicker with each other nearly nonstop. As my mom once said, if they’re loud, they’re alive.

          2. You can be an attentive parent, you can try teach your kids to be sensible, but ultimately kids are a bit daft, and just don’t think of things that occur to you later in life. Like keeping their clothes clean. Kids are also curious, and if one’s never eaten a magnet before and suspects it might be a key to superpowers, it doesn’t really matter how many vegetables you feed them, how many stories you read.

            What I’m saying is shit happens! Source – no kids, but I’m best mates with a 3 year old. We didn’t meet socially, I’m a friend of his mum.

          3. For the record, my daughter was old enough to know better at the time, so it was not a case of me using magnets to post pictures in her crib or anything. She was playing with her brother and pretending to eat the magnet to freak him out when she accidentally swallowed it.

            And remember – every parent is a non-parent until the instant that first kid hits the atmosphere.

  2. Permanent magnets are mysterious… Btw you can magnetize for example a screwdriver by tapping it against something hard (like a vise). VERY useful to remember when you drop that screw where it’s hard to reach…

    1. But that requires a very fortuitous alignment with the Earth’s magnetic field, so your time ahead to keep pick up tool handy a permanent magnet stuck to the side of the tool box. although I am not saying that’s impossible. In the oil field it very common to find a rack of tubing that’s strongly magnetized. Generally tubing ends up being racked in a North South orientation. The tubing takes a lot of ” hammering” as it’s being racked

      1. So how’s that work then? Does the hammering judder the atoms about within a domain, and they find themselves magnetised? I suppose heating is really about giving the atoms enough energy to free themselves, to move around freely enough to be influenced by a magnetic field. Then they cool down and find themselves stuck that way.

        1. Well.. the “hammering” of the pipe is the best explanation that I can come up with to explain my observation. Energy is introduced into the steel, the rack can set undisturbed for months, so I think it possible that the Earth’s magnetic flux acts as magnet keeper. I never stated it’s anything like permeate magnet, because as soon as the rack of pipe is disturbed, it’s no longer magnetic.

  3. [Electricity and Magnetism by Purcell](http://amzn.to/1YkBOWk) reeally helped me get a better understanding of magnets. It explains the magnetic field as really just the electrical field as seen from relativistic inertial frames. Makes all the right hand rules almost obvious and intuitive. Very satisfying (at least for me!). You are still left with the magic of the electrical field, but at least one less thing to have to just accept. Older versions of the book are available for free on the internet.

    1. Yeah, that’s such a completely awesome thing. For the most part relativity is somewhat intangible in our close physical reality, until you realise that something as ‘mundane’ as an electric motor can be said to depend on relativistic effects for its basic function. It just blows my mind even though I have a hard time wrap my head around it completely, but nevertheless it has earned a spot on my ‘favourites of physics’ list.

  4. “As an aside, the nickel plating stands up remarkably well after a two-day tour of the human digestive tract. Source: I’m a dad.”

    Please be super careful with this, there’s actually plenty of cases where people (read; mostly kids) nearly died from ingesting magnets that then connect to each-other in their intestines, clamping off blood flow, with all kinds of scary results (tissue rotting away, leaving holes in intestines etc)

      1. Intrigued; if it was only one, why did you watch/wait for it? Or merely happenstance?

        The human gut is a powerful chemical-industrial warehouse with an amazing ability to transmute. Still remember the first bead I swallowed; went in blue, came out yellow.

        1. Me and my screwdriver, poking at poops in the toilet for like three days. I’m a dad – it’s how we roll.

          Seriously, I just wanted to make sure it made it through without getting caught anywhere.

    1. Just want to reply, to make this comment chain a little longer, to hopefully impress this need for caution in the mind of anyone who doesn’t already see the importance of this warning. Swallowing multiple magnets can be very dangerous. And don’t swallow one since it’s ‘safe’, because then a second swallowed accidentally could be fatal. Also, no MRIs after swallowing a magnet.

      1. Actually I was surprised when I had my MRI, I’ve got some wire and clips that once held my arm together, and the safety questionnaire they make you fill in before is pretty paranoid. To my fairly medium-sized surprise, I felt absolutely nothing. Not a tingle.

        I realise the wire’s not gonna be ferromagnetic, but there’s still eddy currents. But… nothing.

      2. Of course you should not swallow foreign objects. But normally a single magnet would leave your body through its natural exit in one or two days. So only “No MRI” for two days.

    2. There is now just as much danger with button cell batteries. There has been a number of fatalities in my country from children ingesting these button cells. Doctors are too slow to diagnose the problem because it is so unexpected.

      The real problem is somewhat disguised. Because of advances in micro-controller tech and power usage, button cells are far more often used where larger batteries (cells) were once used. Cheap products from you favourite country starting with ‘C’ and ending with ‘hina’ are making it easier for children to access these button cells.

      Button cells provide the electrical energy for acids and alkalise (that normally exist in the digestive tract) to chemically burn though the stomach or intestines. This happens very quickly and needs medical treatment within hours as death can occur within a day.

      Unlike magnets where you need two to cause a rupture – one button cell will cause a rupture on it’s own with certainty.

      1. You sure it’s electrical energy? Not wanting to diminish people with horrible internal chemical burns, but it’s not just the chemicals inside the battery leaking?

        How does that work? If you put a current through an acid / alkali it becomes more corrosive? That’s something I never heard of, interesting!

        1. From medical literature –

          Button or disc batteries are small, round lithium batteries that can be found in various household electronic products including remote control devices, watches, calculators, cameras, toys, games, flashing jewellery, singing greeting cards as well as hearing aids. These batteries are thus commonly found in the home environment. Children can accidentally swallow or inhale these batteries by placing them in the nose or ear.

          When ingested, button batteries mostly pass through the body and are removed in the stool. However, batteries can become lodgedin the esophagus and cause severe tissue injury within 2 hours, delayed complications and even death. For example, around 12.6% of children younger than 6 years who ingest a 20 to 25mm button battery experience serious complications or death (Litovitz et al 2010). Injuries results from direct pressure necrosis, local electrical currents and alkali leakage (Marom et al 2010). Delays in seeking treatment may occur when the child does not disclose or is unable to disclose the ingestionor when the battery is misdiagnosed as a coin on x-ray, leading to complications including esophageal perforation, tracheoesophageal fistulas, exsanguination after fistulization into a major blood vessel, esophageal strictures and vocal cord paralysis(Litovitz et al 2010).

          1. I think this is a much higher danger with Lithium batteries, as they have a higher voltage. I have seen corroded 1,5V batteries in water after quite a long time and 3V li batteries corroded after just several minutes. Also they are bigger. A 20-25mm object in the narrow esophagus of a child does not sound good.

          2. @ [Martin]

            I think that modern button cells hold more energy and can sustain an external chemical reaction for much longer.

            I also believe that with the reduction in power requirements of modern tech, there is nor much more tech stuff that can run on button cells.

            And as you say there is a higher proportion of the higher than 1.5 volt tech out there now.

            In any case I copied the info above straight out of a medical advisory as they’re pretty well spot at getting the most important facts right.

        2. Alkali is corrosive anyway but you do not find it in the stomach. Weak acid like stomach acid is not corrosive to the stomach. But if you electrolyse a solution of salt (NaCl) you can get chlorine and NaOH. one toxic, the other a strong alkaline.

    3. About twoish or so years ago, a child swallowed a magnet only to have it shatter at some point. I’m not privy to why it shattered, but there was real concern about the little bits getting stuck somewhere. I always figured it was in the folds since the magnet should stick to itself, but now I think I u derstand the real concern was it getting stuck “across” the intestinal fold.

      My copies prefer eating nose gold over magnets but it’s still a good piece of knowledge.

  5. I generally throw out the Bohr atom of tiny spherical charges and instead think more about the material in terms of energy, or levels of energy. If I am right, then matter holds a certain amount of energy all the time and it’s how much it has that determines whether it’s iron or carbon or something else. Funny that magnets are notoriously iron and iron is in the middle of the periodic chart where both fusion and fission are capable.

  6. For the record, swallowing a magnet can be really dangerous, and little kids should not be allowed to play with magnets that are small enough to swallow. Particularly if you swallow multiple magnets, or magnets and anything else that is magnetic, the materials can pinch the lining of your digestive track and cause damage.

    1. They feed magnets to cows to catch all the metal junk they eat. there called cow magnets.
      And in addition the girl down the street’s tits are magnetic, every time I see her my eyes get pulled down to her chest?

      1. Cow magnets are usually quite large (less than in inch thick, but a few inches long), and they usually only give one, so there’s no risk of pinching. The problem is when you swallow two or more magnets that are quite small.

      2. Another linked to the Wikipedia article on why cows are feed magnets. Comparing feeding cows magnet to humans ingesting magnets appears to be an exercise in comparing apple to oranges. My guess is that that girls tit’s exhibit magnetic properties as well. As in they are repelled by your leering gaze.

    2. Actually one should not allow kids to play with anything they can swallow and what is not edible. That is why they make DUPLO blocks so big they wouldn’t fit in child’s throat.

  7. Here is an interesting way to observe magnetic domains flipping. 1:20

    A brief and simple explanation of the quantum side. 2:30

    The simple explanation is that magnetism is concentrated electro-static attraction / repulsion.

  8. I’d like to correct a mistake in the article. Permanent magnets hold onto their magnetization by having a large remanence magnetization (M_r, Tesla) as opposed to being due to having a high coercivity (H_c, kA/m), which is a measure of the magnet’s resistance to magnetic reversal from an applied magnetic field. In reality the best permanent magnets are those with a large B-H_max product.

    Source: PhD in magnetic materials and devices.

  9. How do magnets work? “Quantum.” Scientists think they have some idea about it but in essence they know how to make pieces of various metals magnetic, and how to make them not be magnetic.

    The real puzzle is how a magnet can be stuck to the underside of something like a steel bridge girder and it will stay there for, apparently, an infinite amount of time. Where does the energy to counteract the force of gravity come from? If you had that same magnet – demagnetized – and held it up in the same spot with your hand you’d soon get tired of that. You’ve expended a lot of energy moving nothing.

    That’s why magnets are so fascinating to people pursuing perpetual motion. Magnets exhibit properties that look like an infinite tap into some source of energy, so how can that be routed to other use, without expending any other form of energy (heat or mechanical) to get at it?

    1. That’s ridiculous. I can use superglue to hold up something against a bridge indefinitely, there’s no “secret energy” in it. Only reason your arm gets tired is that our m muscles rely on tension, and can’t hold it for very long. Thermodynamics will whip your ass every time, no free infinite energy in this universe.

      1. Actually it’s thinking about such things that brought us E=MC², and although the energy is not ‘infinite’ we can get quite a punch from an atombomb.
        So it does make sense to muse on harvesting the power of magnets in an even more efficient manner too.

        We do of course already do so in a way since all our electrical power derives from generators, which work through magnetism creating electron flow. But that’s like comparing fusion with burning coal, both use matter but not with the same efficiency :)

        Anyway I’d say we should keep thinking, we already got new materials and new chip technology from musing on this stuff, and it’s far from concluded.

        1. No, generators use the kinetic energy that goes into spinning them. No power in magnets. Magnetism is a force, not “energy”, and the article should have been careful about that. When you mention magnetism and accidentally say “energy”, the perpetual motion nuts start getting excited.

          That’s nothing to do with atom bombs, which destroy matter to produce energy. Nothing comes for free.

          1. The correlation with atom bombs, or rather the formula telling us matter=energy times speed-of-light squared, is that you had something we for most of history thought was basically inert like matter, and we discovered (some of) the laws of physics relating to matter enabling us to unlock matter as energy.
            And that is my point, if you know the nature of a fundamental force (since the binding force of atoms is what the atom bomb is about, is it not?) you can do things you did not do before.

            As for generators, your simplification of calling it ‘kinetic energy’ might be a bit much, since it’s kinetic energy forcing a coil to resist magnetic fields, that creates the electron flow.

            And as for ‘nothing comes for free’, it all depends on definition and the amount, gravity ‘comes for free’ as it were, because it doesn’t ‘consume’ anything. And yet it has to conserve the universe’s balance, so it translates into time change. But with forces so large (relatively) that it seems pretty much free. Same with magnets really, they do I would think lose magnetic energy, it’s just not too noticeable because of the scale of forces contained in the fundamental particles.

            Feel free to correct me.

            The pivotal point btw is that the word ‘infinite’ isn’t an absolute but refers to ‘virtual infinite’, as in giving so much energy from so little source material that the resource seems infinite. And that isn’t mad talk since it’s the idea behind fusion reactors for instance, the idea that there is so much energy in fundamental particles that if you manage to unlock it and do a conversion with a good yield the energy becomes seemingly almost infinite.

          2. No, a generator is pure kinetic energy. If you wanted to, you could have a shaft spinning a permanent magnet, and use that to make other magnets move around. Like some sort of magnetic gearbox or whatever.

            The fact that electrons will be dragged around by magnets is because electrons are basically magnetic, they’re the source of magnetism. Pulling round electrons is not too unlike pulling round teeny magnets. Sure, electrons are quantum-weird, but that doesn’t matter in simple magnetics like this, it’s irrelevant. A generator would still work if electrons really were teeny little orbiting balls.

            Gravity might be free, but that’s because it doesn’t give you anything. Gravity can only move things that have potential energy relative to it. You can push a rock off a mountain, tie it to a rope, tie that to a generator. But once you run out of rocks, that’s it. And the rocks got there thanks to the labyrinthine physical processes that made them. There’s no advantage in gravity.

            Gravity doesn’t conserve the Universe’s balance, there is no balance. No energy is being created, only consumed. Things move about as forces force them. Inertia is as much to blame, and that’s not an energy either.

            Magnetism is almost the same as gravity, in many ways. It’s an attractive force. Also a repulsive one, which you don’t get with gravity, but attraction and repulsion are the same thing in opposite directions.

            We didn’t understand atom bombs, matter / energy interchange, but now we do. We also understand magnets. Everything we know about them tells us there’s no energy in there. Sure, an enormous chunk of physics could be uprooted in the future, but there’s no reason to expect that. You could say that about ANYTHING.

            There’s also no need to bring infinity into it, that’s just clouding the issue. A nuclear fusion reactor is only any use if you have a lot of hydrogen. In one sense, the sea, we do. In another, compared to Jupiter, we don’t. A nuclear reactor is not infinite at all compared to the Sun. If we ever get nuclear fusion working, we’ll have to get the hydrogen from somewhere. Given long enough we’d run out, but that’s just relative to how much energy human life uses, which isn’t really relevant to anything Universal.

          3. Saying electrons are magnets is defining something with itself, it’s not an explanation nor does it help your argument in my view.
            .
            And my infinite remarks is about the relativity as you yourself confirm, but the point is that people tend to jump on things when people use that term in an obviously non-absolute manner because they think people are talking about some sort of metaphysical magic. And that’s a bit of an annoying knee-jerk reaction. The original remark I replied on was about magnets holding on for an apparent infinite time and a person replying dismissively about ‘infinite energy’ not being possible therefore it doesn’t use energy to hold on.

            And if you think we know all there is to be known about magnetic energy force (psst: https://en.wikipedia.org/wiki/Magnetic_field#Energy_stored_in_magnetic_fields & https://en.wikipedia.org/wiki/Magnetic_energy) then you are a victim of your own vanity. Or perhaps you can pop over to CERN and tell them to stop wasting effort and money.
            And talking of CERN and research into fundamental physics, anybody working in the area will tell you that there definitely IS reason to expect some rather big discoveries, there are annoying holes in our current models that by the very nature of them require them to be filled somehow, Holes and ‘placeholders’ we use, while being aware they are placeholders.

          4. Whatnot, saying electrons = magnets = electrons, sure it’s defining something by reference to itself, but that’s the way it is. A thing is what it is.

            Sure you could go into 11-dimensional superstrings or whatever, and get a much more complicated answer if you wanted one. But it wouldn’t change the relationship between magnets and electrons. On this level of understanding, that’s what it is. Deeper levels give more detail, but still only back up this truth. It’s boiling it down to what’s relevant.

            When we mention energy “stored” in a magnetic field, are we just referring to the potential energy? As in, the energy it took to shift the atoms in the domains about, and that might be exploited in some manner if you were willing to lose that alignment? IE, a finite source of energy, getting less out than you put in. As far as I’m aware though there is no way of getting that energy back, it just dissipates gradually as entropy moves the atoms back to a random state.

            Sure, there’s always more to learn, science is always just the best explanation we have now for the evidence. But things very rarely overturn. Newton’s laws of gravity aren’t quite right, but they’re still good enough for most purposes. Because they’re based on observation. Even if Newton didn’t know the cause of gravity, he know what it did. And he was mostly right.

            I don’t see why the alignment of electrons causing a force, is going to one day turn out to be a source of energy. The present explanation makes sense as it is. If magnetism were a source of energy, wouldn’t magnets act a lot differently?

            And yep it is an issue where you have to be careful of idiots finding leverage in a gap and pulling all sorts of woo out of there. I realise that’s not your fault, but it’s the Internet, there’s no shortage of people like that. It must rankle particle physicists the same way when someone tries to sell them a quantum healing crystal pendant.

          5. Ah right, just been to the Wikipedia page on magnetic energy. It’s essentially the same thing as potential energy. If, for example, a magnet happened to be at a certain place in a field… say two like poles held next to each other, then it has the potential energy of the movement that will occur when those magnets repel. Once the magnet has been repelled, and all forces are back in balance, then the energy’s gone.

            Of course it doesn’t have to be somebody holding two magnets together. But the point is, it’s just the potential energy of magnetic fields “fighting” each other. Forces that aren’t in balance.

    2. The underside of the steel bridge isn’t falling down. If you bolted the magnet there it would also stay. If you attached a gazillion magnets then the bridge would collapse because it can’t support the weight of the magnates.

      In your example the magnetism is just another form of bonding.

      I think it’s the push back of like poles that fascinate people the most.

  10. I have salvaged many hard drive magnets over the years.
    Whenever the nickel plating peels off, I find that superglue works well to seal it up and prevent the opening from getting bigger. The superglue soaks into the porous exposed surface and forms a protective coating.

    1. How do atoms attract each other by gravity? It’s an intrinsic force. Like the one electrons have, he explained in the article. That’s “how”.

      It’s the way the Universe is. It might not reflect the intuitive way of thinking we have about everyday life, but that’s us failing, not the Universe.

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