Can Magnets Do Work?

  • Added:  2 months ago
  • It's often said that "magnetic force cannot do work." This video is my challenge to this long-taught physics rule.
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    Bonds Do NOT Have Energy!
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  • EducationEducation
  • Runtime: 5:04
  • magnets  magnetism  energy  physics  force  displacement  

Comments: 52

  • doggonemess
    doggonemess Day ago +1

    I before E, except after C. Except in the cases of the arbitrary ways that some English words are spelled.

  • FritzSchnitz Mueller
    FritzSchnitz Mueller 15 days ago

    I have one question: does the quantum spin give the electron/photon/etc their own small magnetic field or is the small magnetic field there because of the magnetic force from outside?
    Thanks, great video as always :)

    • The Science Asylum
      The Science Asylum  13 days ago

      Quantum spin is the cause of the small magnetic field around an electron.


  • FloatHeadPhysix
    FloatHeadPhysix Month ago +1

    The work is done by the electric force, not the magnetic force. Take the wire example. The magnetic field pushes the electrons in a direction perpendicular to the motion of electrons. But these electrons then push on other electrons and atoms, (which is electric push) and that's how the entire wire ends up getting displaced.
    You can replace two magnets with two current carrying loops, (electromagnets), and you will find the same thing. The magnetic force doesn't do work, it's the electric force that would cause the attraction or repulsion.
    O course, changing magnetic fields can do work, but they do so by inducing electric fields.
    You could argue, that we just 'invented' this idea that changing magnetic fields 'induce electric fields' to make sure our statement 'magnetic fields don't do work' stays safe. But then you can go ahead and argue, that there aren't two forces in reality, there is just one, the electromagnetic force. And it can definitely do work.
    So it's all about convenience.
    I like to think that the electromagnetic field can be thought of as made of two parts, one which can do work, and the one that can't. Thinking of it this way allows us to not resort to special relativity and what not :)
    Let me know what you think

  • Rodney Smith
    Rodney Smith Month ago +1

    Something I never thought about..... does a magnet that pulls another magnet to itself use up some energy, and the resultant magnetic field is weaker?

    • The Science Asylum
      The Science Asylum  Month ago

      When you put a paperclip on a magnet, that paperclips electrons line up turning it into another magnet. That has a distance limit though.


    • Rodney Smith
      Rodney Smith Month ago

      So is that why when you make a chain of paperclips off a magnet the force to hold up the next one gets less and less?


    • The Science Asylum
      The Science Asylum  Month ago

      It does actually. If work is being done, energy is being transformed. That energy has to come from somewhere and it comes from the magnets.


  • Rodney Smith
    Rodney Smith Month ago

    My intro Physics class instead stated this as "It takes no work to move a charged particle along a magnetic field line"

    • The Science Asylum
      The Science Asylum  Month ago

      That's more accurate, but physics likes it's rule to be a little more broad than that.


  • STORM CAPRICON
    STORM CAPRICON Month ago

    I have a question ....... so when earth's magnetic field is present which is very strong and we have wire long enough from north pole to the south pole what would happen to the current flowing ( current flowing from north pole to south pole ) ????? Will it go in upward direction like you said ( west or east ) ???

    • The Science Asylum
      The Science Asylum  Month ago

      Well, the magnetic field lines also go from the north pole to the south pole, so if you had a wire from the north pole to the south pole then it wouldn't do anything. Cross products go to zero when things line up. To get the most to happen, you'd have to lay the wire from east to west at the equator. With _a lot_ of electric current (like 150 amps), you could get the wire to levitate.


  • Legojoker
    Legojoker Month ago +7

    This channel deserves more subscribers. Excellent video quality and audience interaction, keep it up.

  • Guest Informant
    Guest Informant Month ago

    0:14 Can I question why there's a question mark after "Question Everything"?

  • Benbedra Abdssamad
    Benbedra Abdssamad Month ago

    There are indeed two types of magnetic forces: a force related to the electric charge and a force related to the magnetic dipole moment as in the Stern-Gerlach experiment, the later can do work if it applied to magnetic dipoles such as atoms.

    • The Science Asylum
      The Science Asylum  Month ago

      Those forces obey the same fundamental laws though. The _laws_ don't distinguish between them even if _we_ want to.


  • Louis-Philippe Chiasson
    Louis-Philippe Chiasson 2 months ago +4

    Insightful, funny, great 'work' as usual!

  • K8UR Channel
    K8UR Channel 2 months ago +1

    Excellent!

  • LouisPowell
    LouisPowell 2 months ago +2

    I'm very satisfied by this video. I'm a big fan of magnets.

  • Avanish Padmakar
    Avanish Padmakar 2 months ago

    if motion leads to length contraction than anything could only contract until plank length so speed limit should be corresponding to that so can we use this to calculate c.also how does information and charge obey noethers theorem??

  • MrDrProf
    MrDrProf 2 months ago +4

    Fucking magnets, how do they work?

  • Daniel Guevara
    Daniel Guevara 2 months ago +1

    Wait I think i misunderstood, in the case of the single particle since its velocity vector is constantly changing direction it is under acceleration. A centripetal force is being applied to the particle which means you are doing work to move the particle. if you increase the strength of the magnetic field the particle will rotate more quickly, and it will gain kinetic energy correct?

    • Daniel Guevara
      Daniel Guevara 2 months ago

      that makes sense thanks!


    • The Science Asylum
      The Science Asylum  2 months ago

      Ah, but if you increase the strength of the magnetic field, the circle also gets smaller. Work isn't done in perfectly stable circular motion.


  • Dijkstra
    Dijkstra 2 months ago +1

    Love this amazing channel

  • Janek Świercz
    Janek Świercz 2 months ago +1

    Awesome video <33

  • The Religious Atheist Bakchodi Corner

    First 200 viewers' club!!!

  • Patrick Skelton
    Patrick Skelton 2 months ago +1

    hey I was told that the work done by a magnet in this instance is due to a changing magnetic force which induces an electric field which is what actually does the work it's a little silly kinda like how the normal force in classical mechanics does no work but it can redirect your pushing force to move an object up a slope similarly a magnetic force doesn't do work but it can redirect an electric force or at least that's how I understand it !?

    • The Science Asylum
      The Science Asylum  Month ago

      The Lorentz force applies to individual charges only. It isn't some universal law that applies to everything. Also, David Griffiths is a bit condescending in his writing, so statements he makes tend to come across more "broad" than they should.


    • caio henrique
      caio henrique 2 months ago

      Section 8.3 of that book isn't *a silly argument*, just because it's not intuitive doesn't mean it's wrong. All the calculations are there. Like the author said, if you think you have discovered an exception in which magnetic forces do work, then please explain why Lorentz law is incorrect.


    • Patrick Skelton
      Patrick Skelton 2 months ago

      ha yeah that is exactly where it's from I think your right it's just as technically the magnetic force is just the electric force in a different reference frame... but yeah that's a silly argument it's like saying gravity does no work Ill have to give you the argument great video love this channel :)


    • The Science Asylum
      The Science Asylum  2 months ago

      That sounds like it's straight out of that book Nerd Clone is holding. It seems like a silly argument for a physics teacher to make when you've got a perfectly simple magnetic force that could do it.


  • blackcarbon95 しょう
    blackcarbon95 しょう 2 months ago +5

    that insect sex though...

  • Andy Kirkham
    Andy Kirkham 2 months ago +10

    Excellent as usual!

  • Gristle Von Raben
    Gristle Von Raben 2 months ago +1

    good video

  • Science Asylum Fan
    Science Asylum Fan 2 months ago +13

    please can you explain why 8 electrons in the outer shell is the most stable configuration???? Why octet rule of chemistry holds true. Why noble gases are stable ? Why is it that octet is stable?? not 7,6,5,4 electrons? Why every atom wants to complete octet to attain stability????

    • what else is on
      what else is on 3 hours ago

      As I (only partially) understand it, fully describing the nature of atomic orbitals and nuclear configurations requires an intimate understanding of spherical harmonics (which I do not have). Good luck with that though.


    • SuperSaiyanShaak
      SuperSaiyanShaak Month ago

      The short answer is that when you (quantum mechanically) calculate the energies of the different subshells (or orbitals is more correct) for an atomic system you see that there are big energy gaps between certain subshells. Where these big gaps occur you call it a new shell ( subshells are classfied based on their angular symmetries) . When a shell is not completely filled it does not cost much energy to add or lose an electron because the subshell just above or below the outermost electron only differs slightly in energy and reactions can thus easily happen. If a shell is completely filled adding an electron cost a lot of energy so this wont happen often( losing an electron is a bit more subtle)


    • Science Asylum Fan
      Science Asylum Fan Month ago

      Legojoker Exactly!! That's what I mean.


    • Legojoker
      Legojoker Month ago

      @The Religious Atheist Bakchodi Corner He's asking about the fundamental principle of why that particular number is stable. Not how humans make nomenclature in an attempt to explain fundamental reality but really end up catching large capacities of the population in shallow answers. The "s p d f, etc. subshells and orbitals" are just geometrically predefined constraints we've placed on the system in an attempt to simplify it. Doesn't answer why this particular geometric and numerical arrangement is mathematically or geometrically stable in the universe we live in.


    • Science Asylum Fan
      Science Asylum Fan 2 months ago

      The Science Asylum OMG!! You're the best teacher ever. please don't forget this.I am eagerly waiting to learn from the best teacher in the world.


  • Kamron Brinkerhoff
    Kamron Brinkerhoff 2 months ago

    I thought the fundamental question would be "Magnets. How do they work?

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