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Gilligan's Island Radio Transmitter!

  1. Jul 17, 2007 #1
    supposedly u are stuck on an island

    battery died on your radio

    u have:

    10 m of wire (copper?) and stuff found naturally on the island

    and u need to run a radio at 3 volts

    what would u do?:bugeye:
  2. jcsd
  3. Jul 17, 2007 #2


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    Gold Member

    Welcome to PF, Physics2grl.
    In keeping with the Gilligan's Island theme, you need a couple of coconuts...
    Seriously, if the battery is the only crapped-out part, I'd gather up a ****load of lemons and limes and use them to make a voltaic cell. (But I still love the Professor and his coconuts. :biggrin:)
    Last edited: Jul 17, 2007
  4. Jul 17, 2007 #3


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    I'd build a house on the island and stay there living the
    good life eating the fruit and nuts and seaweed, unless
    it had major vulcanism / tsunami risks! :D

    Yes, using a lot of lemons and limes might work well with
    the copper, though you'd need some other metal to be
    the other plate in the galvanic cell, and that might be
    a problem.
    Actually I just read a good article on the fruit battery

    You could make a dry pile instead of a citrus fruit
    battery, if you had the right metals to stack:

    If I could find some good lodestone then I could try making
    a generator with it and a coil of the copper wire, though
    I'd have to rectify the AC to feed to the radio.
    I don't recall that very good (highly magnetized)
    natural lodestones are common, though, so that might
    result in quite feeble power output.

    I suppose I could try smoldering some coconut shell or
    wood chips in the absence of oxygen to make charcoal
    as a conductor to work with the copper in
    an electrochemical cell, though I don't recall what voltage
    that might provide per cell... and the resistance
    would probably be depressingly high... hmmm...

    I could make a water drip based electrostatic generator
    and use that to charge a battery, but that'd depend on
    having a rechargable battery, and it'd be problematic since
    the low current and high voltage wouldn't suit a battery
    or radio very well..

    One could use a water stream or water fall or wind-mill
    or hand-cranking to turn a generator once one had one,
    but one would need a good magnet for that to work.

    One might be able to find gold naturally to melt down
    and beat into more wire or conductive plate, eventually.

    Iron ore would be handy and could be smelted from
    natural iron ore oxide deposits to make some chunks
    that could be magnetized and/or used for
    electrochemical cell plates. Though an easier sourse of iron
    might be from iron meteorites that might be found.

    Ah I know, one could use a gold-panning type technique
    or lodestone magnet to help sort out the iron ore
    dust from the beach sand since there's often a lot there
    that's easily sorted out.

    I could enlist the help of Gilligan, Mary Anne, and Ginger
    and have them run around in the sand scuffing their
    feet to make electrostatic charge and have them deposit
    it on a leyden jar capacitor the size of a city block... :)

    It is interesting to think that in only 20,000 years or so
    people have developed such kinds of technologies to
    go from stone age to bronze age to metallurgy / iron age
    to technologies of steam power, chemistry, electronics,
    etc. with most of that change taking place in just the
    last 3000 years.

    I wonder in the course of 40 years how well even the
    most technically educated of us could progress if we were
    left on an island with lots of stone age raw materials,
    ample food/water/shelter, temperate weather,
    but no real technological materials or references for
    construction other than what one could devise oneself.

    Even making fire would be challenging for most people,
    as would making good stone / wooden tools, weaving
    rope, etc. Something like making glass, making a furnace
    capable of melting copper/gold/glass could be quite
    a project.

    Learning to identify and refine/melt/cast the ores of
    zinc, copper, maybe iron would be needed to get to a
    level of technology even ~3000 years old for

    I suppose the easiest radio transmitter would be a
    morse code keyed spark gap transmitter that wouldn't
    need much more than wire, a good dry-pile or
    few leyden jars and water generator, though you'd be
    pretty lucky or very talented to get it to output enough
    of a signal to be useful.
  5. Jul 17, 2007 #4


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    I'd try to do my homework myself before posting it on the internet :tongue:
  6. Jul 17, 2007 #5
    haha, it's a fun topic, but definitely agreed. :approve:

    Joanna Georgie
    student loan consolidation
  7. Jul 17, 2007 #6


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    Science Advisor

    Why do people insist on putting exclamation marks at the end of their thread title? Does it make it seem more important?
  8. Jul 17, 2007 #7


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    Gold Member

    My apologies to the Moderators; it never crossed my mind that this was homework, or I wouldn't have answered it directly.
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