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Do we understand electromagnetics?

  1. Dec 7, 2007 #1
    Electromagnetics has become integral to the existence of the Modern world, we cannot function without man-made electrical power or natural electromagnetic energy but do we really undersatnd it?
     
  2. jcsd
  3. Dec 7, 2007 #2

    Dale

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    Welcome to PF!

    Yes. IMO, the most important and clear test of whether or not you understand a physical principle is if you can build something useful using that principle. If you don't understand, or if your understanding is wrong, the device won't work. However, I am an engineer, so I may have a rather biased view.
     
  4. Dec 7, 2007 #3
    What is the difference between natural electromagnetic energy and man made or is there a difference?
     
  5. Dec 7, 2007 #4

    Dale

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    There is none, other than the fact that man made sources are typically much more steady and regulated.
     
  6. Dec 7, 2007 #5
    And with respect to the develoment of Radio as we know it, radio on our kitchen tables that is, did commercial interest prevent this area of electromagentic development from going further, into let's say more obscure areas.
     
  7. Dec 7, 2007 #6

    Danger

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    Radio itself has come an incredibly long way since it was first discovered, up to the current level of our technological ability.
    Remember that radio waves are simply a section of the EM spectrum, so things like microwave transmitters (and ovens) can be considered radio developments.
     
  8. Dec 7, 2007 #7

    chroot

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    We can build everything from particle accelerators to communications lasers to nano-scale microcircuits using our existing theory of electromagnetics. We understand solar winds and stellar spectra using it. We have successfully applied the theory to systems dozens of orders of magnitude different in size and power. I'd say..... we understand it. In fact, of the four fundamental physical forces, the electromagnetic force is probably the only one we really understand thoroughly.

    - Warren
     
  9. Dec 7, 2007 #8

    chroot

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    As far as radio is concerned, commercial interests are what drive progress. We have communications satellites broadcasting gigabytes of digital data every second through advanced modulations and error-correcting mechanisms. We have $100 cell phones with spread-spectrum frequency-hopping digital communications done in a single chip. We have software radios. We have the Global Positioning System, which basically uses the properties of radio waves to pinpoint a location on the Earth's surface with sub-millimeter accuracy. We have elaborate radio telescopes, hundreds of feet across, which are effectively large radio receivers. Radio has come a hell of a long way since the days of Marconi.... and almost all of the advances have been in the interest of either commerce or military.

    - Warren
     
    Last edited: Dec 7, 2007
  10. Dec 7, 2007 #9
    Beautifully worded. Right up to the bit about Marconi. ~sigh~ Faraday invented Radio. Even patented it. Marconi tried sucessively to steal it in repeated bogus patent claims until one slipped through. Took poor Faraday into the late 1960's to get it reversed. And forty years later they still teach that an unlettered grifter with his one eye on the door and the other to the main chance can be just as brilliant as all the respected scientists in the world as long as he is born a US citizen. It is to laugh, to weep, and perhaps drive some young men postal...lol
     
  11. Dec 7, 2007 #10
    Who in invented radio is arguable and its an old one and will be bashed out for years to come, George Francis Fitzgerald and Hertz are wonderful pioneers, I have often wonder what if they and Maxwell went another direction, where would we be? Assuming they did go another direction can any of you imagine where that might be and what might have happened?
     
  12. Dec 7, 2007 #11

    ZapperZ

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    You are going somewhere with this whole thing. I don't know where yet, but I don't see any physics content in this, or else Maxwell equations would have been featured prominently in why you don't think these are satisfactory in understanding electromagnetism.

    Since this is more of a "historical" issue and not physics, I'm moving this to the GD forum.

    Zz.
     
  13. Dec 7, 2007 #12

    russ_watters

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    We'd be right where we are today. Radio was an invention - radio waves are not.
     
  14. Dec 9, 2007 #13
    I can see your point of moving the post to a degree, I suppose I want to lead the discussion into a creative platform technically if you wish to move the post there because you feel creativity is not part of physics then do so but if not think about it and then anser accordingly, apologies if that sounds snotty it is not meant to be, maybe we should start a new thread entitled can theoretical technicians incorporate imagination and creativity into their conversation but I would prefer for the thread to remain where it is and have people engage with it as so.
     
  15. Dec 9, 2007 #14

    chroot

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    jonourd,

    We decide where posts go. You should also recognize that ZapperZ is a professional physicist, and knows quite well the role of creativity in science.

    - Warren
     
  16. Dec 9, 2007 #15
    We only have elaborate models of how electromagnetic waves might behave. But truly, no one knows what it is. Just like in models of atoms, electrons are orbiting the nucleus, in quantum mechanics models call for electron clouds to describe atoms, which is amazingly accurate. In the untested yet string theory, particles are modeled to be vibrating strings of energy. Sounds great, but still we have no idea what everything is at the most fundamental level.
     
  17. Dec 9, 2007 #16

    russ_watters

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    I guess I'll take a stab at this: Are you suggesting that if people's creativity had led them in different directions, Maxwell's equations would look different than they do now?
     
  18. Dec 9, 2007 #17
    Simply because we have theories that can predict the outcomes of electromagnets for an extreme degree, does this really mean that we fully understand it?

    In my electronics class I learned about the right hand rule. I have no problems with it and I know how to apply it. What bothers me is that we even have a right hand rule. If we lived in a mirror universe then couldn't it be a left hand rule. Why can't it work equally well in both directions? I don't think anyone can actually answer the question why, all they do is show evidence to prove that it is. I've learned to accept the fact and live with it.

    But still, how can something work well in one direction but not equally well in the other?
     
  19. Dec 9, 2007 #18

    Gokul43201

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    Last edited: Dec 9, 2007
  20. Dec 9, 2007 #19

    Astronuc

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    The reference orientation and nomenclature are arbitrary, but the relationships involved at what they are. We look at natural process and try to describe them as best we can. The fact that we can predict reasonable well outcomes of experiments, and we can manipulate materials to build generators, motors, lasers, CPU's and other microelectronics, lights, radar, microwave ovens, . . . . indicates that we understand EM pretty well.

    The RHR or LHR reflect something of the duality of nature. In a Cartesian coordinate system, on any of the three principle and orthogonal directions, one either goes forward or backward (reverse) - two choices. In rotation in a plane (2D) - one either goes clockwise or counterclockwise - there is no third choice.

    Please provide an example.
     
  21. Dec 9, 2007 #20
    Examples are all around us, and I think you're reading far more into it than needed. If you took a text book explaining the right hand rule and changed every place that said "right hand" to "left hand", and every place that said "left hand" to "right hand", it wouldn't work the same. The fact that the rule only works in one direction allows us to build DC motors and have them rotate in the desired direction every time. Simply because you can explain the cause of the right hand rule in great detail still doesn't negate the fact that it rotates in only one direction perpendicular to the flow of electrons through a wire. Passing the blame to something else that spins in only one direction at a subatomic level still doesn't answer my question. So then I'm just left asking, why would that only spin in one direction and not the other? It just goes on and on and on. It's as if God flipped a coin and said "I think I'll have it work this way".


    And I really don't care because we made some cool toys with it. ;)
     
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