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Ball lightning caught on tape!

Discussion in 'Electronic Basics' started by ngdbud, Sep 30, 2005.

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  1. ngdbud

    ngdbud Guest

    For any of you who watch Maximum Exposure (max-x), this week they
    played "Earth, the Most Dangerous Planet in the World". they played a
    small section on lightning, tapes of lightning strikes. there was an
    electrical storm somewhere and a guy went out with a camcorder when a
    lightning bolt struck above his head on the gutter of his roof. First
    you see the trees in front of him light up like it's day time, then the
    guy starts screaming and the camera shakes a bit, then you see this
    soft white ball spiral away from him and then vanish without a sound.
    I'm not an expert on ball lightning and it's one of my more vague areas
    of science, so correct me if I'm wrong. I have the show on my DVR and
    hope to post the clip on my website this weekend. Here's the url to my
    site, http://www.geocities.com/ngdbud/, It's a brand new baby and so
    far just a picture page. I GURANTEE IT WILL TAKE A WHILE TO LOAD!!!! I
    have told some people on the Tesla List (www.pupman.com) that I would
    post the clip from Mind Freak of Criss Angel getting zapped by a tesla
    coil. This clip takes priority and due to Yahoo's incredibly small
    storage space I may not have enough room to post the ball lightning
    clip.


    While i'm on the topic, another clip from the show had a lightning bolt
    strike a wet soccer field knocking something like 5 players down and a
    few sent the hospital in ambulances. Is this just a clip of under payed
    soccer stars sucking up to the camera? It seems like the field,
    especially being wet, would be incredibly conductive, but not
    latteraly. Besides, Why would the electricity bother to run through a
    human bady only to go back to it's startting point, the ground? Seems
    pretty ify to me.
     
  2. BobG

    BobG Guest

    While i'm on the topic, another clip from the show had a lightning bolt

    ngdbud:
    strike a wet soccer field knocking something like 5 players down and a
    few sent the hospital in ambulances. Is this just a clip of under payed

    soccer stars sucking up to the camera? It seems like the field,
    especially being wet, would be incredibly conductive, but not
    latteraly. Besides, Why would the electricity bother to run through a
    human bady only to go back to it's startting point, the ground? Seems
    pretty ify to me.
    =========================
    My buddy Billy works for the power company. He says the explanation is
    the current dissipates away from the strike radially on the ground. Any
    poor cows in the field facing toward or away from the strike get a
    differential current across their poor little hearts from front hooves
    to rear. Those lucky bovines standing side to the strike live to tell
    the tale... This was one of his stories.Other life saving tips.... if
    your truck has a hot line across it, be sure to jump out, dont step out
    with one foot in the truck, one on the ground. He had another one about
    hopping toward a guy that was holding a wire, rather than walking with
    2 feet on the ground across the voltage potential. Orlando PD had a
    police horse keel over dead downtown for no reason. Poor old fellow.
    Heart gave out? A week later, same officer on a different horse, sane
    place, same deal... horse keels over.... the steel horseshoes in front
    were on a hot manhole cover at 480v or something, back was on solid
    ground.
     
  3. Guest

    Guest Guest

    : latteraly. Besides, Why would the electricity bother to run through a
    : human bady only to go back to it's startting point, the ground? Seems
    : pretty ify to me.

    The way I think about this is to think of a circuit with parallel
    resistors across a voltage source. If one of the resistors is much larger
    than the other, the current through the larger resistor is much smaller,
    but is not 0. Current traveling from the water, through a person, to
    ground is another, much higher resistance path from the current traveling
    from the water to ground directly, but there is still current in that
    path. If the current is large enough, it can cause problems with the
    body, or even death.

    Hope that helps,

    Joe
     
  4. Art

    Art Guest

    Seen the effects in Flordia many times, Tampa, Ste. Pete area and south
    towards Port Charlotte. Amazing but dangerous!!
     
  5. Jasen Betts

    Jasen Betts Guest

    contrary to popular belief electric current does not exclusively take the
    path of least electrical resistance (or the shortest path) if it always
    took the path of least resistance turning on the toaster would make the
    lights go out.

    If it always took the shortest path extension cords woudn't work.


    when the lifgtning strikes the ground near of impact there's a voltage
    gradient in the ground of some hundereds of volts per foot,

    a soccer player with his legs apart will experience that voltage.


    What electricity does do is take the path that provides the lowest voltage
    drop

    Bye.
    Jasen
     
  6. Ban

    Ban Guest

    Why? What makes you believe it is not like this, BTW it is the lowest
    *impedance* taking frequency dependent parameters in account. But for 50 or
    60Hz the resistance will usually be dominant.
    I do not follow you, or do you mean the insulation?
    Don't say hundreds, it's thousands or even tenth of thousands! Anybody will
    feel it, not only soccer players.
    You are smart, aren't you
     
  7. ehsjr

    ehsjr Guest

    Say what?
    Right. And it also takes the path the provides the highest
    voltage drop, and all paths of all voltage drops in between.
    So the statement is meaningless.
    Source---+---[Z1]---+---Return
    | |
    +---[Z2]---+
    | |
    +---[Z3]---+
    | |
    ~ ~
    | |
    +---[Zn]---+

    Ed
     
  8. Jasen Betts

    Jasen Betts Guest

    but it doesnt work like that. if it did and you attached two different
    resistors (in parralllel) accross a power source _all_ the current would
    flow though the lesser.
    no I mean if that (shortest path) were true it'd be impossible to impose
    a longer path... the appliances plugged directly into the outlets would
    get all the current because that's the shorter path...
    I didn't say how near... maybe I was thinking 10 times further from the
    point of inpact. the OP mentioned soccer players.
    you got that right :)

    Bye.
    Jasen
     
  9. Jasen Betts

    Jasen Betts Guest

    read it again... if electricity always took the path with the lowest
    resistance and since a toaster has a lower resistance than most lightbulbs.
    turning on the toaster would offer a lower path or resistance and the
    electricity would flow that way.

    This is a form of argument called reductio ad absurdum, showing that soome
    claim is false by showing that it requires some absurdity.


    I guess I could have expressed that better. (but i'm not sure what to add)

    suppose n=2 and Z1 is a 10v Zener diode forward biased and Z2 a 10V zener
    reverse biased, or Z1 a 10mm spark gap and Z2 a 1mm spark gap.

    Bye.
    Jasen
     
  10. John Fields

    John Fields Guest

    ^^^^^^^^^^^^^^^^^^^^
    reducto ad absurdium
    ---
    Not _some_ absurdity, but by reducing it to the absurd.
    ---
    ---

    All you have to do is show that the charge which flows out of a
    voltage source is shared by loads connected to it in parallel:

    <--11A
    +---[+10V-]---+
    | |
    | 1A---> |
    +----[10R]----+
    | |
    | 10A--> |
    +----[1R]-----+
     
  11. ehsjr

    ehsjr Guest

    Perhaps, but I should have read it better. I got your point
    the second time I read it, so the failure is mine.

    Ed
     
  12. Rich Grise

    Rich Grise Guest

  13. I just looked, load time was about a minute through a cable modem
    connection known to achieve 2 Mb/sec, and no ball lightning stuff was
    there yet.

    Meanwhile, I suspect this incident was what I suspect many instances
    of "ball lightning" to be: Drops of molten metal.
    Most molten metals have very high surface tension, and drops can be
    quite large - like large peas or even in some cases marble size.
    People seeing an incandescent drop of molten metal rolling along and
    unprepared for such a thing can easily mis-estimate the size and
    brightness.
    Drops of molten metal do not reliably scorch what they touch. Sometimes
    sufficient moisture is present for steam to keep the metal drop airborne.
    When the drop actually touches things, it usually does not wet things -
    especially not most nonmetallic materials. People who do welding don't
    get as many scorched spots on their clothes as they get smaller drops of
    molten metal hitting their clothes.
    Drops of molten metal can bounce and "skitter", and may leave a spotty
    trail of scorched spots.

    Aluminum and iron sometimes actually burn, and molten drops of these
    metals in some cases can burn and stay hot enough to glow brightly for a
    little while.
    Wet soil is only a fair to moderately good conductor. The soil may even
    be fairly dry and may not yet have had much rain soak into it.
    Lightning sometimes strikes before much rain has fallen. Lightning
    may even strike outside of the region that receives rain from a
    thunderstorm. There are even cases where thunderstorms form while the
    humidity in the lowest mile of the atmosphere is so low that the rain
    largely evaporates before hitting the ground. Ever hear of "dry
    lightning" being a cause of forest fires in western parts of the USA?
    With the lightning delivering peak current in the 10,000's of amps, the
    voltage gradient along a radius from the strike point could be
    significant, and someone with feet at different distances from the strike
    point while close to the strike point could get quite a jolt. Sometimes a
    single lightning strike can electrocute a few head of cattle this way.

    - Don Klipstein ()
     
  14. Doug McLaren

    Doug McLaren Guest

    | My buddy Billy works for the power company. He says the explanation
    | is the current dissipates away from the strike radially on the
    | ground. Any poor cows in the field facing toward or away from the
    | strike get a differential current across their poor little hearts
    | from front hooves to rear.

    Another bit of data -- generally when lightning struck the ground,
    nearby cows were killed, but huamns survived. The ancient greeks felt
    that this was because they were more `divine' than the cows, but
    ultimately it's a two feet vs. four feet thing, sort of what you
    described.

    | Those lucky bovines standing side to the strike live to tell
    | the tale...

    Talking cows? :)
     
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