Mullardman
Moderately extreme...
So... 'permanent' magnets.. anyone?
That's the reason behind the somewhat convoluted "not disproved" double-negative language you were quite naturally wondering about in the post you commented on and in my post assuming what that one referred to. This makes me think that perhaps in a forum I ought to drop "correctness" for the sake of clarity.
Runs out to buy some cable lifters…
Then there's the hypothesis that there is only one electron in the universe.
Newton's theory of gravity held up for a long time
I'm not sure of the question but magnetism comes down to spinning electrons. I did find a good explanation by one of my favourite lecturers (and Nobel prize winner) Feynman but it has quite a bit of maths and I remember you telling us that you didn't study Chemistry beyond ONC as you couldn't do the maths.
Think of an old penny made of copper. If you look from one side you see a head and the other a tail but both are the same penny made of copper. You can think of the electromagnetic force in a similar fashion. They are both the equivalent force but appear as either a magnet or a charge depending how you look at it. (I'm going to get shot down for this explanation but it gives an idea without any maths). Thats why you can get a magnetic field from electrons and an electric field from magnets.
Not all elements exhibit strong magnetic fields but quite a few have weak and very weak fields.
When I taught science I held a large iron rod and aligned it in the Earth’s magnetic field. First I showed that the rod didn't exhibit any magnetism as both ends of a compass were attracted to each end. I then whacked the end of the rod aligned with the Earth's field with a hammer and showed that the rod was now magnetised as it would both attract and repel the compass magnet. I could then demagnetise the rod by whacking the end with the rod rotated 90 degrees to the Earth's field.
Science is fun no?
DV
PS Linky to the lecture https://www.feynmanlectures.caltech.edu/II_34.html
I don't know, but whatever it is that holds an iron bar (or anything solid) together, is the same as holds a magnetic iron bar together. Not sure if that is "energy" since it never seems to run out. The magnetic property is thought to be about how the electrons are aligned or arranged. I am not sure that any additional "energy" is required.Actually, I never came across any chemistry which required maths which was beyond me. It was the course which required the Maths. But let's not labour the point.
Thanks DV but I already knew the practical stuff about hitting things etc. I also have a laymans understanding of the relationship between coils and moving conductors etc. Also, in a very real and practical sense, it doesn't matter much what causes a permanent magnet to be a permanent magnet. So, if it is down to spinning electrons, I'll take that. That really isn't my question.
Let me put it this way... If a permanet magnet picks up a piece of non magnetised material, and then holds on to it.. then surely some energy is involved? So the question becomes.. where does that energy come from? It seems to me that the energy does not reside in the magnet. It is not, in other words..some sort of 'battery', as permanent magnets do not generally 'run out of magnetism', unless maybe heated, or subjected to shock or whatever.
So.. if the 'energy' employed by the magnet to do it's thing does not come from within the magnet.. then where from?
That is why I have always understood permanent magnets to be effectively devices which somehow interact with the Earth's magnetic field, and that is where their magnetic 'energy' derives from. Hence my question. What happens if you take a permanent magnet away from the influence of Earths (or any other) magnetic field?
If I have this completely wrong..where does the 'energy' of a permanent magnet come from..and why for practical purposes does it not run out?
Actually, I never came across any chemistry which required maths which was beyond me. It was the course which required the Maths. But let's not labour the point.
Nothing. It keeps on being a magnet.What happens if you take a permanent magnet away from the influence of Earths (or any other) magnetic field?
Thats correct up to ONC/'A' Level but the next step upwards HNC/degree does. I remember my first term at Uni reading Chemistry and we had 4 ladies in the class. In that first term we had Schrödinger’s wave equation and quantum mechanics both involved quite complex Calculus. I don't know if your ONC syllabus was the same as mine but the endorsement (optional) maths paper went into both differential and integral calculus in preparation for the degree-level work of HNC/BSc. Oh and those 4 ladies? In term 2 there was only one remaining............
Cheers,
DV
What do you think my ‘like’ was for?P.S. I'm a bit miffed that nobody seems to recognise Reluctance as a genuine electro/magnetic term. I'm a relative ignoramus and I've heard of it.. Try to keep up chaps!
That most ladies are unable to do maths, apparently…and your point is ?
Let me put it this way... If a permanet magnet picks up a piece of non magnetised material, and then holds on to it.. then surely some energy is involved? So the question becomes.. where does that energy come from?
You cad... I’m imagining that being spoken in a Terry-Thomas voice...Oh and those 4 ladies? In term 2 there was only one remaining............