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Teaching relativity to the general public

  1. Mar 31, 2015 #1
    In the light of this policy https://www.physicsforums.com/threads/what-is-the-pfs-policy-on-lorentz-ether-theory-and-block-universe.772224/ [Broken] , is it now considered acceptable to teach relativity by starting out with Lorentz Ether Theory (LET) and its Newtonian time which appears to be substantially easier for people to understand than the normal approach? The Internet is filled with confusing sites teaching relativity which categorically state that time is not Newtonian and which order the reader to start thinking about it in a radically different way, and yet it now seems that the more intuitive LET is considered to be the self-same theory as Einstein's, merely attaching a different philosophical interpretation to it. I have spent several years looking into this to try to find out how Lorentz's theory was disproved, and it has come as considerable surprise to me to find out that it is actually still standing, just hidden out of sight behind Einstein's version the theory.

    During the course of my research, it has become clear to me that many of the usual claims made about relativity are actually just unbacked assertions associated with philosophical interpretations which have no actual support from experiments, so it now strikes me that it is highly unethical to teach them as if they are facts, and yet that is how they are taught almost everywhere I look. Given that professional physicists are "generally content with the minimal interpretation and uninterested in philosophical interpretations", would it not make sense for everyone who introduces people to the subject to switch now to the simpler philisophical interpretation which doesn't require people to deal with a radically different nature of time (which most people never manage to get their heads around). Clearly it would still be wrong to provide only one of the philosophical interpretations or to assert that that approach is correct while failing to teach the other main interpretation, so it would be essential to teach both in order to ensure that the teaching is thorough and balanced.

    What do people think about this?

    (Please try not to turn it into an argument about which interpretation is best as an explanation of reality - this should be kept tightly focussed on education.)
     
    Last edited by a moderator: May 7, 2017
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  3. Mar 31, 2015 #2

    Khashishi

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    I don't think it is advantageous to teach LET to students, since almost all literature covers SR, and this will just present mixed messages.

    Secondly, SR is more minimal than LET, so your argument is backwards.
     
    Last edited: Mar 31, 2015
  4. Mar 31, 2015 #3
    I was thinking mainly about the general reader rather than a student of physics.

    I can't see how it's more minimal when it involves greater complications when teaching it and leaves many people unable to get their heads round the subject at all. Surely the aim should not be to remain shackled to existing teaching approaches which fail many people and to try to make the subject more accessible.
     
  5. Mar 31, 2015 #4

    Khashishi

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    I don't believe many students who are confused by SR will find LET any more understandable. You are assuming this to be true. On what basis?

    SR generalizes to general relativity much more easily than LET. It is unavoidable to get into geometry when it comes to general relativity, and Lorentz transformations are just coordinate rotations in a curved spacetime. It is not clear how ether behaves with gravity.
     
  6. Mar 31, 2015 #5
    I find that many people simply can't get past their own philosophical objections - they tend to reject special relativity out of hand on the basis that it makes no sense to them. They then give up on it altogether, and that's a shame when they could have learned a considerable amount through the LET approach (covering time dilation, length contraction and the headlights effect while exploring simple, rational mechanisms by which these things could occur), and that would have taken them to the point where they could then have gone on to learn SR without the same hostile incredulity about the basic facts as to how things behave in space, and then they would have found it easy to go on from there to look at GR.

    That may well be true - I haven't looked in detail at how LET handles gravity yet, but then there's a dearth of good reading material on that subject at the moment and I can only find explanations of GR.
     
  7. Mar 31, 2015 #6

    PeterDonis

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    PF's policy has nothing to do with how it is or is not considered "acceptable" to teach relavity. PF's policy is solely concerned with what topics of discussion are acceptable here on PF. The purpose of the policy is to avoid having long discussions about things that cannot be resolved in this forum.
     
    Last edited by a moderator: May 7, 2017
  8. Mar 31, 2015 #7

    PeterDonis

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    I have moved this thread to the education forum since, per the OP, it is intended to be a discussion of how to teach relativity.
     
  9. Mar 31, 2015 #8
    While it makes some sense to put it in this forum, sadly it also means there are unlikely to be any more useful replies as it is now in a section which the people whose advice I was seeking are unlikely to visit. That means I may now be forced to make important decisions without getting the input of the most qualified people available here, and the consequence may be that a government will make a switch to introducing relativity in schools through the LET approach.
     
  10. Mar 31, 2015 #9

    Khashishi

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    You should be aware that Lorentz praised Einstein's work. He abandoned his own ether theory after subsequent work by Poincare and Einstein.
     
  11. Mar 31, 2015 #10

    wabbit

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    I would just say that to me as a layman the most interesting thing in SR is relativity itself (of time, space, etc). I'd feel cheated if taught LET, or most likely I wouldn't have gone past the first two pages of a book that taught that at the time I was first exposed to SR, as it would have looked like a bunch of obscure formulas for specialists who need to work with high velocity situations, something I had no particular interest in. Add to that an arbitrary undetectable ether and the book would have hit the dustbin:) On the other hand SR was immediately interesting precisely because it questionned the notions of absolute time and space and explored the idea of relativity and more generally a relational view of space and time. This is just a personnal view but the reason I m interested in physics as a layman is the ideas, not the formulas.
     
  12. Mar 31, 2015 #11

    PeterDonis

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    Your OP said nothing about "making important decisions". In any case, PF is not in the business of making decision recommendations.

    Do you consider that a good thing or a bad thing? From your OP it would seem that you consider it to be a good thing since you believe it would be simpler and more intuitive.

    The other obvious question, if this is really about how SR is going to be taught in schools, is, aren't there standard textbooks in the field? For example, Taylor & Wheeler's Spacetime Physics? Is there some issue with just using those? From what you're describing, it seems like you think there are no resources out there and you're having to make up your own teaching materials. That does not seem plausible to me.
     
  13. Mar 31, 2015 #12

    PeterDonis

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    This statement, and others in your post, make me think you either have not looked at, or have not understood, standard textbooks in the field, such as the one I mentioned in my previous post. If you are trying to put together a curriculum for teaching SR in schools, you should not be using random things you find on the Internet. Physicists who are experts in this field have spent years putting together textbooks for the express purpose of teaching SR. Those are what you should be using.

    Some other good references by experts are listed here:

    http://math.ucr.edu/home/baez/physics/Administrivia/booklist.html#special-relativity
     
  14. Mar 31, 2015 #13

    wabbit

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    Regarding your statement that it might be unethical to teach SR as fact.

    This does sounds a bit strong to me - I don't expect a teacher at an introductory level to start with a long explanation about what the limits of the theory he is going to present are, and which parts should be regarded as interpretative etc - I'm happy to learn the basics first and get the provisos afterwards or for question time, and wouldn't complain about unethical behavior there.

    But mostly, if this is so, then teaching LET surely is just as unethical for the same reason ? Or do you feel compelled to teach both at the same time?

    And finally surely there's nothing wrong with presenting SR by saying "and it turns out that if we drop the assumption that... and intead make the assumption that ... then everything suddenly looks simpler and more natural", which is by the way more or less how I remember it being presented.
     
    Last edited: Mar 31, 2015
  15. Mar 31, 2015 #14

    PeterDonis

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    I think it would behoove you to check into SR's experimental support (which is quite extensive) before making hasty judgments about what should or should not be taught as fact. Once again, you should not be using random sources on the Internet to decide how to teach SR. You should be using the best efforts of experts in the field.
     
  16. Mar 31, 2015 #15

    Nugatory

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    Are you saying that input (or lack thereof) from an anonymous Internet forum might be the basis for a decision to make such a switch?
     
  17. Mar 31, 2015 #16

    PeterDonis

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    I find this statement a bit puzzling in view of your post #8. Are we just talking about SR for the general reader, or are we talking about actual schools and school curricula?
     
  18. Mar 31, 2015 #17

    Nugatory

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    An example of such a claim would help us understand the sorts of things that you see as problems in need of correction.
     
  19. Mar 31, 2015 #18

    Wes Tausend

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    In my opinion, one of the best brief information sources regarding Lorentz, Einstein's SR and Poincaré, is this short, animated, 1/2 hour video called The Lorentz Transformation from Annenberg Media. Scroll down and click on #42, accept the pop-up and it should load. Similar videos have also appeared on PBS TV extra channels in my area.

    It does seem that the OP may not be familar with the logical reasoning behind SR, and this CIT produced presentation should help. In addition, all these video series are suitable for high-school and introductory college classes. The one downside is that the programs are only downloadable in the USA and Canada. I haven't viewed them all, but, again, I suspect all the other of the 52 video physics series are also quite good.

    Wes
    ...
     
  20. Mar 31, 2015 #19

    atyy

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    Yes. See Bell's "How to Teach Special Relativity" reprinted in https://www.amazon.com/Speakable-Unspeakable-Mechanics-Collected-philosophy/dp/0521368693. Rindler also comments https://www.amazon.com/Relativity-Special-Cosmological-Wolfgang-Rindler/dp/0198567324 (p43) that "in SR every inertial frame is as good as absolute space". From LET one can derive Minkowski spacetime, and from Minkowski spacetime one can derive LET. In classical physics, they are the same theory.

    The situation is a bit delicate in quantum mechanics, and one can see "Bell's theorem" for discussions. I believe the physics is correctly discussed in these papers, but there is a debate nonetheless about the interpretation of history.
    http://arxiv.org/abs/1402.0351
    http://arxiv.org/abs/1503.05017
    http://arxiv.org/abs/1503.06978
    http://arxiv.org/abs/1311.6852
    http://arxiv.org/abs/1503.06413
     
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  21. Mar 31, 2015 #20

    wabbit

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    Yes but isn't that missing the point ? Who is being taught here and to what purpose ? What makes it worthwile to teach LET rather than SR ? So far the argument has been that it's easier - but is this true of the students, or is the problem with the teacher ?
     
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  22. Mar 31, 2015 #21

    atyy

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    I added some comments about quantum mechanics to my post above :)

    One more paper about quantum mechanics and LET/Minkowski: http://arxiv.org/abs/1111.1425.
     
  23. Apr 1, 2015 #22
    Lotentz perhaps wasn't as bright as Einstein and he missed a few tricks, such as the way to show that there's nothing ad hoc about length contraction in LET. He gave up on something that turned out to be easy to show.

    That shows that you don't know how LET can be taught. It can all be done by using a computer screen to represent the fabric of space with pulses of light always moving across it at a fixed speed. When you do that you can easily show why time dilates in the way it does and why length must contract too (not to force things to fit in with the results of experiments like MM, but for a mechanistic reason). When you draw out the light paths it's then easy to do the maths using trigonometry to work out the slowing of clocks and the degree of length contraction for any speed of travel through the space fabric. It is the clearest possible way to introduce the subject and to make it obvious to all the leraners that these effects must happen. The normal SR explanation is much harder to follow, but it most certainly does need to be taught as well.

    The arguments against the idea of a fabric of space and an absolute frame of reference cause many people to throw the whole idea of relativity in the dustbin because it conflicts with their ideas of how nature works. As soon as you tell them that there is no absolute frame at all (not even an undetectable one) they think you are asking them to believe in contradictions - the accounts of events from different frames directly contradict each other and cannot all be true (in one frame of reference, rocket A accelerates away from rocket B and the ticking of its clock slows down, but in another frame of reference the ticking of its clock speeds up instead - it is not possible for both of these things to happen at the same time). However, they are usually thinking in LET-like ways with a Newtonian time when they apply these objections. When they think it through with time turned into a dimension, they then run into a similar issue where rocket A accelerates away from rocket B and ends up taking a shorter path into the future when you do the analysis from one frame of reference while if you analyse events from another frame of reference you find that it takes a longer path then rocket B instead, so there is still an nasty contradiction there which for philosophical reasons (i.e. logical/mathematical) they cannot accept - they think there must be a special frame in which the longest path into the future is available. All interpretations run into a version of the same issue in one way or another.

    You're right about that being interesting, and there is no question that SR must be taught too. I think it's doubly interesting to look at both sides of the argument though and not just to teach one.

    I'm connected with a political party which is exploring the idea of radical education reform - there is a package of software under construction, but I cannot say more than that, although introducing relativity in primary schools would be very much on the table.

    Having looked at it carefully, I do think it would be a good thing, but I'm looking to see what objections there might be to it from the physics world in general, and the best talent at the top physics forums deserve to have a chance to have their say.

    The approach in all the existing books I've looked at has a common problem - a complete failure to address the philosophical objections to SR, and it's that that leaves many learners looking on relativity as witchcraft. As for finding a book for schools teaching LET, that's a tall order, but there is some superb software under development for this. In general though, almost all the teaching materials currently used in schools fall a long way short of where they should be - there is a continual need to replace almost all of it with new materials which are clearer, more comprehensive, and they should also be optimised for self-teaching. That really means a shift to interactive computer programs, but the most important thing is to get the content right and in the case of science to make it absolutely clear what is fact and what is mere assertion. Far too many people are being taught to believe in philosophical baggage that is not backed by experiment, and that's doing science a disservice.

    There is no question of just cobbling together random things found on the Internet. The plan is to put together the best package possible, learning from everything that has been done before. The current approach is clearly failing because it generates swarms of qualified people who belive some of what is merely philosophical baggage to be fact even though it has no experimental backing. That is unethical and it must be stopped - it is a sign of education failure.

    Thanks - I will check them all.

    Any teaching materials which assert that time is not Newtonian or that there is no absolute frame of reference are passing off assertions as facts. I've found university textbooks making highly misleading claims which help to fix ideas firmly in people's heads in the fact compartment even though they are just assertions. Misleading claims should have no place in education. Most importantly though, even if you use textbooks which never overstep the mark in any way, you still need to be aware that the learner will be encountering information from many other sources which will likely push them into believing that various key assertions are facts, and that needs to be countered actively by arming them with an understanding of which parts of SR are merely assertions (i.e. philosophical interpretations). The most powerful way to do that would be to teach them about LET too so that they can see a viable alternative interpretation of what is officially regarded as the same theory, and then any assertion which conflicts with LET will be immediately recognisable as assertion rather than fact.

    Both should be taught, and in each case the assertions tacked onto them must be labelled clearly as assertions.

    That is something that should certainly be done with the assertion that there is no special frame in SR (similar to the absolute frame in LET) - if the idea that there could be a special frame is discussed (and the assertion that there isn't one is correctly identified as a mere assertion), the objections based on contradictions (in the accounts generated by the analysis done from different frames) are wiped away at a stroke and the SR/GR models are not damaged by that at all. It's when you do that that the disbelievers suddenly begin to open the door to SR and regard it as potentially viable instead of something that defies reason.

    There is no experimental evidence that there is no absolute frame. There is no experimental evidence that time is not Newtonian. There is no experimental evidence that the speed of light is the same relative to you in all directions. Many assertions are pushed as if they are facts, and for every source of information that frames its claims with greater care, there are a hundred others which don't. By teaching LET in addition to SR, you arm the learner against being misled by the bombardment of false claims which they will inevitably encounter. The most damaging source of misinformation is the TV science documentary where professional physicists overstate the case time and time again, pushing assertions as facts. Education needs to counter that by arming learners with sufficient knowledge to be able to tell when the truth is being simplified out of something or when a physicist is merely pushing a philosophical interpretation.

    One has to look at the whole picture and cover all the most important sources. If you think asking the opinion of people here is not a good idea, then I cannot agree with you. I have already found it useful to hear the various objections/comments.

    It is an opportunity for people to have their say. I am leaning towards going with LET as an introduction to relativity, so I'm looking to see if anyone can provide good reasons why this should not be done.

    Children do not all go on to be physicists, but they do grow up to be adult members of the general public with all manner of ideas and beliefs stamped into their heads from their upbringing. Many of them then frequent science forums as members of the general public who have an interest in science and who believe they have a little knowledge too. They then push assertions as if they are facts, piling in against anyone who questions any of their learned beliefs, and this shuts down rational discussion.

    Einstein's assertion that there is no absolute frame of reference is a prime example - that is just his philosophical interpretation and not a fact, but it is pushed almost everywhere as if it is a fact.

    Thanks - I'll have a look at that.

    As someone who works in AGI system development, I specialise in logical reasoning (and linguistics). I will not discuss the role of this in education, but there is a link. I have explored the logical reasoning behind SR with extreme care and have only found two issues with it, one of which can be eliminated easily by recognising the logical need for a special frame of reference (which can't be identified) in any interpretation of SR. The other issue relates to the role of cause and effect in a universe where a photon can jump billions of years into the futrue in zero time and find the future fully built for it without having to wait for that time-section of the universe to be generated from the earlier part over billions of years, but that is only a problem for the block universe interpretation of SR and need not damage SR itself. Again it is important to provide a robust education into the different interpretations because so many physicists appear on TV asserting that gravity is not a force (rather than stating that it may not be and that it depends on a particular interpretation of SR being correct), and as soon as you try to eliminate it as a force you are taken into the block universe model where all causation is eliminated and replaced with lucky accident.

    Thanks - I'll look into all of those.

    I think it's an easier way into the subject, but more importantly it arms the learner against the avalanche of misinformation which they will encounter later on. As it stands, most people (including large numbers of professional physicists) have mistaken assertions for facts and learned them as such. In doing so, they have created a climate in which an alternative interpretation which is still fully viable is being treated as if it doesn't exist, generally considered to be obsolete or disproven. That is not something which real education should be playing along with because it would be to provide a distortion of the truth. There is certainly no need to go the other way and spend hundreds of hours exploring LET, but two or three hours spent on it right at the start could make a huge positive difference, showing everyone that relativity is not some kind of magic which can't be visualised easily, but that it's an obvious (once you've seen it) reality.
     
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  24. Apr 1, 2015 #23

    wabbit

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    Honestly, I don't really care how it's taught, my point is whether it's something useful or interesting to learn early on.
    Yes, you can learn the Lorentz transform without the need for any deep thinking, though at the cost of accepting some rather unnatural if not bizarre explanations. But to what purpose ? Aside from SR, I see the Lorentz transform as a specialized tool for dealing with high velocities. What is the value of teaching it to a general audience?

    And since you agree that SR needs to be taught, then why not just do it instead of teaching the two ?

    Again, I don't see the value of teaching LET except later in the process - both for its historical interest, and because by stressing that we can pick any frame and declare it absolute, this can enrich the understanding one has of SR. So in my view LET is an interesting topic for advanced students, while SR is essential much earlier.
     
  25. Apr 1, 2015 #24

    wabbit

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    You have a point, though I would think a better solution to that would be to teach with a view of relativity earlier. Absolute space is an unnatural concept which has no basis in common experience, and I believe is only acquired because it is taught. Avoid teaching that bizarre idea, and people will find it much easier to forget it later and integrate also relativity of space and time.

    Regarding your comment that there is no proof of no absolute space - of course not, but that is not the point. There is ample evidence of space as a relational phenomenon, i.e. of relative space. Absolute space is just a possible hypothetical entity one can add if one likes, with no evidence making it necessary. We can add many other hypothetical entities that do not break the models, but these only distract from what matters.
     
    Last edited: Apr 1, 2015
  26. Apr 1, 2015 #25
    If you teach it the right way, it's extremely interesting and useful, providing a direct understanding of why things like time dilation and length contraction must happen right at the start.

    The idea is to teach it initially without using the Lorentz transform - there is a much simpler way to explore it.

    Because the way the LET model would be taught is much simpler and clearer.

    Declaring it absolute is not a good idea, but treating it as if it is absolute is fine.

    Absolute space is a natural concept which young children automatically think up for themselves. Initially they think the Earth is anchored to it, but later they determine that the Earth is rotating and moving through it instead. Then they are taught about relativity and they have assertions pushed at them which many of them don't feel make sense. I think a better way to deal with this is to start with LET which makes immediate sense to them, and then to introduce SR and to look at the issue of absolute space there, at which point you need to explain that a lot of the baggage attached to SR is just assertion and that it does not need to be accepted in order to get a working understanding of the model. Your idea of trying to hide the idea of absolute space from them is actually just you trying to impose a philosophical interpretation upon them by avoiding looking at a philosophical interpretation which you disagree with. To do that would would be to distort their education.
     
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