I was talking with a friend about a design for a perpetual motion machine that used magnets, but he said that magnets eventually lose their magnetism. I don't want anyone to go into how Thermodynamics disproves perpetual motion, I just want someone to answer this question: Do magnets ever lose their magnetism, and if so how long does it take?
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I have a bunch of magnets (one of those game-board thingies) given to me when I was a school-going lad over 20 years ago, and the magnets feel just as strong as it was the day it was given.   As a corollary to this question , is there a way to determine how long a permanent magnet will remain a magnet?   Addendum: Would two magnets remain a magnet for a shorter duration if they were glued in close proximity with like poles facing each other?
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How is it proved to be always true? It's a fundamental principle in Physics based on all of our currents observations of multiple systems in the universe. Is it always true to all systems? Because we haven't tested or observed them all. Would it be possible to discover/create a system that could lead to a different result? How are we 100% sure that energy is always conserved? Finally, why did we conclude it's always conserved? What if a system keeps doing work over and over and over with time?
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If I was to take a bunch of magnets and arrange them in a sphere (And keep them there with glue or plastic or something) so that the north pole faces the outside of the sphere and the south pole faces the inside, would the magnet have the same pole no matter what way I turn it or would the magnet be neutralized or something.  I'm envisioning a sphere made of magnets so that no matter what way I turn it it is always the same pole and that a bunch of these repelling each other would be really cool, is this possible?  In effect would this create a monopole magnet?
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So this Youtube video has been around for a while now  . Also this  may be related.  I just wanted to know if there is any standard hydrodynamic terms to explain it. Derek clearly states it is not about Bernoulli principle, as in this case the ball rotation is important.  Has any recent paper/videos discussed what happens if you do the same experiment with hydrophobic spheres? Can it be predicted with laminar flow theories or does it need turbulence?  Too many questions have been posed, but not so many responses on the internet yet.  Edit: I said Derek stated "it wasn't Coandă effect", yet what he says is that it is not "just Bernoulli's principle". Coandă effect is the typical hairdryer ping-pong ball levitation which is explained by Bernoulli's principle.   Edit2: rephrasing.  Additional comment: There seems to be two explanations "water adhere to the sphere and is ejected conserving horizontal momentum" and "Magnus effect" (ME). The later is not so obvious to me as the system is in equilibrium and there are two fluids, water and air, (does ME means air pushes the ball horizontally?).   Edit3: DESCRIPTION To avoid rot links and people that do not want to see the video, I'll try to explain the phenomena. You have a sphere and a water jet. The water jet is vertical (opposite to gravity), and touches the sphere almost tangentially. The ball not only rotates due to the water jet but also stays at constant height from the ground. The angular velocity can be defined in the direction of the cross product between the position of the contact point between the jet and the sphere (origin in the center of the sphere) and the direction of the jet. Some water drops fly away at the top of the sphere away from the jet.  Edit4: New question, would this phenomenon occur if there was no air?
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What would happen if the earth would stop spinning? How much heavier would we be? I mean absolutely stop spinning. How much does the centrifugal force affect us?  If you give technical answers (please do), please explain them in laymen's terms, thanks.  Edit: I am asking what would be different if the earth were not spinning. Nevermind the part about it stopping.
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What exactly are the spikes, or peaks and valleys, caused by in pictures such as these    Wikipedia states that "From the point of view of magnetic energy, peaks and valleys are energetically favorable", but I'm not exactly sure what that means, or how it works. Why isn't the fluid just happy being attracted to the magnet in a semi-sphere shape? Could it be that it gains a magnetic charge, so it attempts to repel itself at the same time? Just pulling at straws here.
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There are many videos on youtube in which people arranged magnets in circle and rotated one placing in middle of that circle on a shaft, and the magnet (magnet motor) starts madly and continues its movement. Do they really rotate infinitely? If so, do they from where they get that extra energy to move so fast and infinitely?    EDIT: This question is about real world scenario  UPDATE: I am unable to find that particular video about which i talked about -- I added them to my favourites, but they are all now deleted :( -- there are hundreds of that that kind of videos. Some example videos links
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What do we mean with  and ? I can not find a way to relate magnetic monopoles and dipoles with electric ones. I do not understand their outcomes. Also,what is their role in Gauss' law for magnetism (the net magnetic flux through a closed surface is zero)?  I read that the magnetic dipoles are essential for the meaning of this law. Why? If magnetic monopoles existed,then why would the law not be valid? Lastly,why do we say that the magnetic field is divergeless? Some physicists try to find a magnetic monopole (something Dirac tried to explain i think). So if they actually find one, what does that mean? For a classic magnet(N-S) we know that we have charges inside moving in a circular motion and they althogether form that magnetic field of the magnet. So how does finding a magnetic monopole change this? What does it mean for those small currents?    (I might understood something wrong here so enlighten me please!)
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Or does it exist mathematically?  Is it really inconsistent with a common-sense, mathematics or known physical laws?   As far as I understand, if it exists, it must be far away from the "positive" matter because of repelling force, so it explains why there is no observations of such matter.   It would be also very consistent with the idea that the total energy of the Universe is zero. Doesn't it imply that the total mass of  the Universe is zero?   Can you please clarify the statements below that seem to contradict each other?  1)  -Max Tegmark.  2) Despite being completely inconsistent with a common-sense approach and the expected behavior of "normal" matter, negative mass is completely mathematically consistent and   3) Such matter would  and show some strange properties, stemming from the ambiguity as to whether attraction should refer to force or the oppositely oriented acceleration for negative mass.
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As of this writing it has been made clear to me that classical physics' Luminiferous aether was a terriblly poor discriptor of space. With the advent of Special Relativity and General Relativity, that aether ceased to be applicable. Today I began reading on the Higgs boson, and the Higgs field. How are those theories different from or similar to the seemingly irrational Luminiferous aether?  P.S. I am a first year student at Bakersfield Community College. If this question seems naive, you now have an explanation.  (EDIT) To me the similarity rests upon their fundamental influences regarding static positions in space. I currently only accept models in which static spacial positions are impossible. Contrastingly relative positions seem quite reasonable. In my humble opinion my naivatisms inhibit me from absorbing and understanding the Higgs boson. If they actually are similar, public protest would probably be more apparant. However, I have put forth my best effort to pose an direct question here.  P.S. The questions Where does space go when it falls? and What happens to time lost when matter accelerates? come much earlier in my studies, and they seem relevant.
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What's an atomic superstate/, and how is it possible?  I understand the basics - being something can be moving and staying still at the same time; the observer changes the behaviour - but I'd like to know a little more, as it interests me, and how is it possible without actually interfering with said thing?
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There is iron in our blood, which is magnetic. Roughly how strong would a magnet have to be to induce a noticeable attraction? It would be nice to know this for several distances. Also, do electromagnets that strong exist?
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In  someone mentioned that it couldn't happen. Why not?   For example I asked about the speed an object would have to move at sea level to create a vacuum behind it; in the comments someone asked what I meant by vacuum because there couldn't be a perfect vacuum.
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I'm having trouble understanding how a  (not the  that is generated as a result but the material itself) work. The particles are aligned in a specific direction to give rise to force but I don't see how this alignment gives rise to "attraction" or force.
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When I first started using computers, law of the land in computer class was never bring magnets near anything computer related, lest you lose all your data or screw up your monitor.  Now I am pretty sure magnets will still royally mess up a standard hard drive, and I know for a fact they screw up a CRT monitor.  Though I am also pretty sure they do not screw up a LCD monitor?  Now I have my phone which uses magnets to determine if it's docked, and it made me wonder.  Is it the power of the magnet preventing data loss or the sheer fact that whatever memory type in the phone is immune to it?  What about ear buds, as I know those have tiny magnets in them. Are those capable of damaging any electronic device currently in use?  I'm wondering if I'm being paranoid, but I really am not sure what magnets will damage and what they won't!  Is there a list, or rule of thumb for determining what will be hurt by magnets and what won't be?
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If I move a magnet towards the coil then the magnet will experience a restive force because of . This way mechanical energy will convert into electrical energy.  But what if the magnet and the coil are a sufficiently large distance apart? The change in the magnetic field travels at the speed of light so the magnet will not feel any restive force instantly. Doesn't this violate the energy conservation law? Because we fix the magnet to a particular point before the restive force arrives at the magnet. And we will able to produce arbitrarily large energy in the coil.  If the magnet starts to move at time t=t1 and lets assume that t0 is the time taken for the flux linking the coil to change due to motion of the magnet.  t0 = (distance between the magnet and the coil/velocity of light)  the magnet will begin to experience resistance at time (t1+2t0). so the delay will be 2t0. In this time period (2t0), magnet is free without experiencing any resisting force. During this time period we can draw current arbitrarily large value by making arbitrarily large numbers of turns of the coil. If energy is conserved, then what mechanism stops us to draw any large amount of power from the coil ?
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Can magnetic fields be "blocked"? For example, in the game, TitanFall, a robot stop bullets with ( presumably ) a magnetic shield.  I wish to calculate the magnetic force required to stop a bullet within a few microseconds.  But the problem I have is that my entire electronic system or the vehicle ( most likely even a building ) will be subjected to massive fields most likely destroying it as well.  Does any know of a way to "block" or divert the field around my vehicle? Is it even possible? My knowledge in magnetic fields are quite limited at this time.