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  1. #1

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    A Question That Just Poped Out Of My Mind

    Hi All,
    I am realy reluctant to post this question. It seams silly. But here it is: Do magnetic fields impact emulsion formation. I always use a magnetic stirring barr.I wonder if I would get different results with an overhead mixer.
    Sorry about this,
    Bill

  2. #2
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    Don't know why I am answering this -- beyond the fact that I loved the title...I was trying to figure out how His Holiness, the Pope, became a verb

    But what is there in emulsions that would be affected by magnetism? Iron compounds? I don't believe silver is. Interesting question, tho!

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  3. #3

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    Yes Vaughn,
    I left out a "p".
    I believe that molecules that are not "magnetic" can be affected (temporarily) by a magnetic field. I don't think that MRI exams depend upon iron compounds in the body being examined. Its a temporary re-alighnment of the molecules.
    Bill

  4. #4
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    Magnetic fields do not affect emulsions.

    Bill, I used a magnetic stirrer to make my emulsion at the workshop.

    PE

  5. #5

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    The property you want to look up is called "diamagnetism", and silver is diamagnetic. Materials that are diamagnetic will reply themselves from a powerful magnetic field. If I remember right, it has to do with the electrons forming "eddies" or their spin being affected by the strong magnetic field, which I think tries to line them all up with the same spin (i.e. up or down). This allows the magnetic field generate a mild replusion by the atom.

    It's pretty weak, but in college, we make some metal complex in the lab and then took a vial of the material, suspended it from a wire attached to a 5 place balance. We put the vial into an electromagnet, and weighed the vial. We then turned on the electromagnet, and then the vial was either lighter or heavier - I forget which. We then took the difference in the two weights and then I think tha mass of the metal complex, and then we figured out the diamagnetic constant for that complex.

    So while PE says that magnetic fields have not effect on emulsions, we can have it both ways - Silver compounds can be affected by magnetic fields in that they are diamagentic, but their diamagnetism has no effect on emulsions.

  6. #6
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    Quote Originally Posted by wildbillbugman View Post
    Yes Vaughn,
    I left out a "p"...Bill
    Thankfully it was not an "o"!

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  7. #7

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    Thank you, Kirk,
    I also have mind-pops like:Was there ever a man named "No-Sir Arafat"?
    But thanks for the intelegent reply. I knew there had to be something in the dark,remote corners of my brain that caused me to sudenly think of that question.

    Bill

  8. #8

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    Interesting topic.

    I once observed a silicon stopper that had an appearent "magnetic" effect in that it could change the reading on an electronic scale I was using to measure chemicals... when brought close to yet w/o touching it!

    Also of note, it absorbed the pink dye of the bag I had stored it in...
    becomming quite pink (and not only on the surface!) after storage in the dark for more than a year or so.

    After the discoloration occurred, it seemed to have lost most of its "magnetic" effect, having only a doubtful to immeasureable effect.

    Never hesitate to talk/ask about the mysterious.

    I still think it is amazing that the earth is round and yet we dont fall off.

    Ray

  9. #9

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    Ray, I'd suggest it's not mysterious, but static electricity.

    It's the bane of people that do a lot of weighing of really dry objects at less than 0.001 g precision. Dry beaker, dry evaporationg dishes, they can drift for some time, especially when the air that day is dry.

  10. #10

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    In praise of the internet...

    Quote Originally Posted by Kirk Keyes View Post
    Ray, I'd suggest it's not mysterious, but static electricity.

    It's the bane of people that do a lot of weighing of really dry objects at less than 0.001 g precision. Dry beaker, dry evaporationg dishes, they can drift for some time, especially when the air that day is dry.
    Yes of course that is a possible explanation.

    But at the time it did not appear so; there was no clingy tissue "magic", and
    there was no appearent dissiptation of the effect, being repeatable again day after day, the "charge" being constant over both time and handling.

    In any case, I submit the opinion that what is or is not mysterious is in the eye of the beholder and even in the face of appearent scientific understanding, there are somethings that for some people remain amazing and mysterious.

    Besides, much "understanding" rarely exceeds what is akin to an illusion;
    It seems there is always something held out of our view, off stage so to speak and that is where the mystery resides, in the unconscious and in that twilight between the conscious and the unconscious.

    Yes.

    Well, I am just curious, I understand that silicone materials tend to collect electrons and become negatively charged... if this was the case what would you expect the scale to do? Increase or decrease?

    Other materials are known to release electrons and become positively charged... would you expect them to affect the scale differently?

    How do those people you mention that do a lot of weighing of really dry objects at less than 0.001 g precision, handle the problem?

    Is the earlier or later indicated weight to be taken as the most "accurate"?

    In the case I described, when in direct contact there was not really any additional drift observed, it was rather magnetic like, increasing suddenly and uncontrollably, as distance neared zero, yet being completly reversible when seperated again.

    Not having anyone to guide me through the problem, I found my own solution.

    I have no doubt that had you been there we would have found a solution; I think it jollyluckygood that if such a problem arose today, your (and many other's) input would be available.

    Ray

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