exchemist

Oh I see. Well that's a win, then! It's been an interesting discussion.

One important difference, though, is that in the OP's machine the poles of the two magnets are opposed so that they repel. The region in which the fingers on the input disc move is in principle an area in which the field lines will be squashed outwards in the plane of the fingers of the disc.

OK, in that case, what I think you will find is it takes significant effort to pull the finger out of the gap, as the force of attraction is stronger once the magnets have moved inward, than the force that pulls it into the gap when you insert it. So you do net work on the system that way and this provides the energy that restores the stored energy in the fields to the status quo ante.

Won't the answer depend on what the products of decomposition are going to be, as well as on the enthalpy change, which may heat the mixture further ? Both of these will depend on what your undisclosed compound is. Also, why do you speak of "lava"? Lava is molten rock and rocks do not ignite, as a rule.

OK, now we get to it. In your proposed machine, the magnets first repel one another, doing work and lowering the stored energy in their respective magnetic fields. You believe that when you insert the steel finger between them, they will then be attracted towards it, doing more work and further lowering the stored energy in their fields. And then, when you move the finger out of the way, they move apart again due to repulsion, extracting yet more energy from their magnetic fields. This obviously cannot be the case. So there is something wrong with your assumption. Either you will find the magnets are not attracted together when the steel finger is interposed, or you will find the finger resists being inserted or removed, such that the operator has to do work against the field, thus supplying the required energy. At the moment (being a chemist rather than a physicist) I am not sure which of the two it is, but logically it must be one or the other, it seems to me. My suspicion is that the magnets will not be attracted to the finger. If you consider the path of the flux lines when the finger is in between, they have to turn sharply horizontal within the finger and pass outward to each side. This I think means the dipoles within the finger will not be able to align themselves with either field in the way that you (implicitly) suppose, as they will be perpendicular to the fields, and so no attractive force will result. If that's right, you would be able to twiddle the finger wheel as fast you like and bugger-all will happen! But perhaps you should build it to confirm exactly how it fails to work.

I think you are overlooking the time and effort it takes to nurture a human baby. Before modern human societies arose, you needed two parents to raise a child, because of the long time it takes before a young human is independent.

The biological aspect of your question has already been addressed in your previous thread, hasn’t it? The social observations you now make seem on the face of it a bit ridiculous. If you really think the way the scout movement is organised shows the male of our species is becoming irrelevant, it looks as if you are getting things out of perspective. But I note the reference to your mother. Are you a Boy Scout, or something?

This is stupid. A computer is not just wires. Only an idiot thinks that. Nor is a brain just a mass of biochemical wiring, either. Try to apply a bit of sense, for goodness sake.

It's very simple. W=Fd is all you need to keep in mind. If there is no change in d, the distance in the direction of F, no work is done. Move them apart and you do work on them, causing energy to go into the magnetic field (a form of potential energy). Allow them to move closer and the reverse happens: they do work on whatever is holding them apart, with the necessary energy coming from the magnetic field. As for the magnet sliding, that is a distraction. It does not in fact alter the strength of the magnetic force holding it to the metal sheet. Any motion perpendicular to the force means d does not change, so no work is done. (What it may do, though, is reduce the frictional force parallel to the sheet which resists the magnet being slid. Typically the frictional drag between two surface that are sliding past one another is less that the limiting friction just before the force is overcome and sliding commences. This is to do with asperities on the surface interlocking, which does not happen to the same degree when they are in motion. But this is a tribological digression.)

That's interesting, I had not realised the extent of the outbreak internationally. But it went away on its own, apparently. At least, I don't recall any vaccination effort being publicised. I had thought that was because the transmission process was not such as to enable an exponential spread, so it became self-limiting.

Indeed. However, But when a magnet and something attracted by it move closer together, under the influence of the force of attraction between them, work is done. I am saying this comes from a reduction in the stored energy in the magnetic field.

Interesting about Chatham. I was surprised to see from the castle battlements an old (decommissioned?) submarine moored in the river, just downstream of the bridges carrying the railway and road. I might pop down the line from Victoria again some time and take a look. I think it's the next stop after Rochester. Back on the topic, yes there will be work done when the magnet and steel object move relative to one another under the influence of the force from the field. W= Fd, remember. But when the magnet is static, held to the beam by its magnetism, no work is being done. I think that is what @swansont meant by saying magnets don't do work, i.e. they don't do work when they are just sitting there, simply by virtue of being magnets, as it were! And there is no inexhaustible store of energy in a permanent magnet that you can draw on by incorporating it in a perpetual motion machine. There is finite (fairly small) energy imparted to it when it is magnetised and you can get a bit of that back, once only, by allowing an object to be drawn towards it. But if you separate them again as part of an operating cycle of some machine, you have to put the same energy back each time. So as I say, no free lunch.

Yes I think I recall smallpox vaccine was the solution last time it started to spread in a few Western countries. But it fizzled out pretty quickly, with or without vaccination. We had a few eyeball-rolling hysterics who thought it was armageddon, but it was a false alarm. It's going to take more than an article in the Daily Batshitograph (as I'm afraid it has now become) to get me to take this new story very seriously.

There was a minor outbreak of monkeypox recently, but I’m not aware it became a recognised epidemic. As I recall, there was no more than a few hundred cases.

I was out yesterday (visiting Rochester, on the Medway, a very interesting town with a Norman castle, a c.12th cathedral and a rather fine old high street with a lot of history) so have only just seen this. A permanent magnet has energy in its magnetic field. This energy was imparted when the magnet was first magnetised, aligning the magnetic dipoles of the atoms. A permanent magnet is thus in a metastable, higher energy, state, compared to one that has become demagnetised. What happens when a piece of paramagnetic or ferromagnetic material comes under the influence of this field is a bit complicated but I think in energy terms it is something like the following:- The magnetic dipoles in that material are induced by the field to align with it. This costs energy, relative to the previous field-free, non-aligned state and the energy required comes from the field of the permanent magnet. So there has been a potential energy transfer from the permanent magnet to the material that is being attracted to it. The potential energy of the system can be further lowered by allowing the two objects to move together. It is the stored energy in the field of the permanent magnet that is responsible. (This is made clear when you consider the work you have to do to pull the two objects apart.) But any repeated process involving separating and moving together permanent magnets simply moves energy into and out of the field. Energy can only be extracted from it once, in the phase in which they move together. After this there is no free lunch. Yes I suppose that makes sense. Does it make sense, I wonder, to speak of the radiation distribution having an entropy? What you seem to suggest is that the black body distribution has the maximum entropy of any radiation distribution.

Perhaps a short digression into the philosophy of science is appropriate. Science develops models of nature that enable correct predictions of the behaviour of nature to be made. Very often these models are recognised as approximate or incomplete and thus to have a certain scope of application which should not be exceeded. Newtonian mechanics is a good example. Nobody says Newtonian mechanics is "wrong" but it doesn't work at the atomic scale, nor when relative speeds are a significant fraction of c. We all know this and use Newtonian mechanics with those limits in mind. The magnetic circuit model is evidently quite successful for many engineering purposes, provided one doesn't stretch the analogy of its fictitious magnetic "current" too far. It is a scientific model insofar as it makes correct predictions for how nature will behave. If your model tells you a static magnet continually does work, though, you have a major problem, because you need to explain where this energy appears, what its source is and why this source never runs out. So at that point your model fails.

I suppose that depends on what is meant by "brighter". In terms of radiation intensity, I'd have thought one could increase that beyond the intensity of the source, if it is an extended source. But clearly one can't change the frequency of the photons merely by focusing a beam, so the effective temperature (if is black body radiation) of the radiation can't be altered. in that way. Is that what you meant? Apart from the bit about separating coincident poles, which seems to make little sense, this may work fine for you, for macroscopic magnetic or magnetised objects. The weakness is it can't connect macroscopic behaviour to what goes on at the atomic level or connect magnetism to other scientific phenomena. So it's basically reverting to a c.19th, pre-atomic theory, picture. I've seen this before with some people from an engineering background on science forums. I suppose they prefer the mastery of nature which c.19th physics seemed to achieve, before the inconvenience of the invariance of the speed of light, the ultraviolet catastrophe and the photo-electric effect forced a rethink. If you are happy with staying in a sort of steampunk, H G Wells era world, well OK. Most of us prefer deeper explanations, that connect to other scientific phenomena.

OK I understand what you mean and I'm aware there is a "magnetic circuit" model used in engineering: https://en.wikipedia.org/wiki/Magnetic_circuit However this has drawbacks if used incautiously, as is in fact mentioned in the article. There is in truth no magnetic "current", as nothing flows. Whilst we habitually draw flux lines with arrows on, these do not indicate a flow of anything. The magnetic field is a vector field, i.e. it has both a magnitude and a direction at any point in space. The density of flux lines is used to denote magnitude and the arrows denote direction. That is all the arrows mean. A field is not a current. (This is explicitly stated in the section of the Wiki article subtitled "limitations".) As for whether this way of thinking of magnetism is a better description, we have just seen how it has given you the wrong answer, in the example of the magnet stuck to a beam. So clearly it has severe limitations. The circuit model may be fine for analysing the shape of the field in electrical machines and so forth but, as with many models in science, it has limits and if these are not borne in mind it can make you look a bit of a berk! 😀 I had not heard of Ed Leedskalnin (not Leedskillin), but I see he was a Latvian immigrant to the USA who was active in magnetism between the wars. I also see that indeed he was on the right track in interpreting magnetism as arising from circulation of charges within the substance, just as I described to you in my previous post. His understanding was thus a foreshadowing of what we understand today about magnetism from atomic theory, quantum physics and quantum chemistry. (Quantum theory was developed in the late 1920s and 1930s, possibly a little later than when he was writing about magnetism.) P.S. Curious fact: magnetism can in fact be shown to arise as a consequence of applying the theory of special relativity to electric charges in relative motion. I think that is rather cool.

I’m a chemist by training, so I am very much aware that chemical bonding is electrostatic. Every solid object gains its solidity due to electrostatic attraction, between atomic nuclei and their surrounding cloud of electrons. It is this that bonds atoms together in solids. Magnetism is only different in that it arises from electric charges in relative motion. In a permanent magnet the atoms have unpaired electrons, which have angular momentum, circulating and/or “spinning” and this motion creates a magnetic dipole on each one. These align and their collective dipoles combine to create the magnetic field of the magnet. Unless it is an electromagnet, in which case, the field arises from the flow of electrons (electric current) in a coil of wire.

Magnetic attraction. If you have a bolt screwed into the beam, all that holds it in place is actually electrostatic attraction, because that is what is responsible for the chemical bonding in the metal that enables it to keep its shape and resist deformation under stress. There is no difference in principle. Don't be fooled by how biological muscles work. Those do expend energy to hold a weight in a static position, but that's to do with the biochemistry of muscle fibres. My example of the bolt screwed into the beam is what you need to consider. That does not expend any energy, not even if the bolt supports a 1 tonne weight suspended from it! Or think of a concrete support holding up a weight. If you did that by your muscles, you would get tired, but the concrete is not doing any work to hold the weight up. Work is only done if something moves under the action of a force. So a crane lifting a weight does work against the force of gravity. But if the operator stops work for lunch and leaves the weight hanging there from the cable, no work is being done. So there's no energy accounting to do in the case of the magnet. A magnetic force or an electrostatic force can both equally hold something in position against the force of gravity, in the right circumstances. There have been a few on this forum. My favourite was Tom Booth's "ice engine". He got banned in the end but that was for failing to take in anything anybody said, not because he was proposing a perpetual motion machine. Unusually, that was a perpetual motion machine of the 2nd kind. But it was a crank classic in that it was all based on Tesla [groan]. I had not realised that among his many eccentricities, Tesla thought you could run a heat engine using ambient heat. There was also, on another forum, aJapanese who thought an IR photovoltaic cell could be put in a fridge, light a bulb and cool the fridge. So that was another 2nd kind example. Tom Booth was interesting in that he had researched the history of thermodynamics and put me onto a paper by Sadi Carnot (in translation) in which he, Carnot, was applying the idea of caloric, i.e. before the modern concept of heat even existed, and nevertheless was able to get the right answers!

That, we were all sure, was the intended joke. We hoped he would win , so that he would have to be announced at the prize-giving ceremony. Sadly, he got knocked out of the competition in one of the heats.

This comment of yours illustrates exactly what I feared about your grasp of physics when it comes to magnets. No work is done by a static magnet sticking to a beam. Mechanical work is a force applied through a distance, F x d. You would not think a bolt screwed into the beam was continuously doing work by staying there, would you? So why do you imagine a magnet sticking to a beam is doing work?

I recall a competitor in one of the single sculls events at Henley Town Regatta who registered to race in the name of H Janus. This was in the days before the Amateur Rowing Association insisted on ID membership cards. Calling your son Janus seems an invitation to trouble, whether or not you know your Roman deities.

Jan, for men at any rate, is not a nickname but a full name, being how John (Jean in France, Iain in Scotland, Yann in Brittany) is rendered in a number of Continental languages. Jan as short for Janet is a female nickname, though.

Well, as someone who once long ago trained as a patent agent, I rather like perpetual motion machines. It can be fun sometimes to analyse them mechanically, without resorting to the easy thermodynamic way to dismiss them, just as an exercise. But at the same time I have some sympathy for the moderation at this other forum you mention. When one sees an apparently pointless machine like yours, which has a shaft output nominally the same as the input but with a needlessly complicated mechanism, especially one involving magnets for no obvious reason, alarm bells ring, (especially if one has been around on science forums for a few years as I have) and one tends to think, "Hello, that smells like a perpetual motion machine to me". Some of the stricter forums don't encourage mental exercises with perpetual motion cranks. By the way, it seems to me your machine can pass power backwards: if you were to give your rotor a spin so its arms passed through the magnet gap at a rate similar to the rate at which the magnets were made to reciprocate by turning the output shaft, I think it would align its speed with the reciprocating motion, rather like a synchronous motor aligning with the frequency of mains AC.