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Please Debunk:Ghost Swing

  1. Sep 17, 2007 #1
    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Sep 17, 2007 #2
    A hoax is of course a possibility, but somehow that behaviour reminds me of the rattleback. It rotates back and forth around the vertical axis at the same time it starts swinging. Could it be that something tricky happens with the chains, and it is taking energy out of the wind?
     
  4. Sep 17, 2007 #3

    turbo

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    C'mon! The wind-noise in the microphone of the video cam is deafening. Is it a little bit possible that the seat of that swing is acting like an air-foil? Let's see the hoaxters (or the incredibly gullible) film the swing on a calm day.
     
  5. Sep 17, 2007 #4
    But there's something tricky happening, because only the middle one starts to swing. The wind is the same for them all.
     
  6. Sep 17, 2007 #5

    turbo

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    Do you think that somehow, the sling-type seats of those mass-produced swings are shaped exactly the same? I'm not willing to make that assumption.
     
  7. Sep 17, 2007 #6
    I mentioned the possibility of the wind causing this in my first post, so certainly, it is not my point to start proving that wind would not be the cause. But what I'm saying is, that that is still a non-trivial phenomenon. Resonance seems to be a key issue at least.
     
  8. Sep 17, 2007 #7

    turbo

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    You need to factor in the speed of the wind (high in this demonstration) the direction of the wind, the constancy of its speed, and the shape of the swing seats. This is a complex situation and you can't wave it away by throwing out "resonance" or any other buzz-words. If this effect is not repeatable under a wide range of conditions, you should get back to basics and try to piece together some realistic dynamics that might explain it. It won't be easy, simple or clean.
     
  9. Sep 17, 2007 #8

    DaveC426913

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    I have little doubt that this is a wind-related phenom, though that only explains it to some extent. There is certainly something intriguing going on.

    Some things to take into account:
    1] in the first clip at about 0:55, a piece of litter blows across the scene, indicating the direction of wind seems to be crosswise to the swing axis.
    2] the microphone seems to pick up the worst noise when the cameraman is pointed crosswise to the swing (though I don't know what that says about wind direction)
     
  10. Sep 17, 2007 #9
    This reminds me again of the rattleback! I have a feeling, that that is counterintuitive, but still very well fully physical. The rotational motion around vertical axis, originally caused by the wind, somehow gets transformed into the swinging motion.
     
  11. Sep 17, 2007 #10

    Ivan Seeking

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    I don't see this as being any more amazing than a sailboat.
     
  12. Sep 17, 2007 #11
  13. Sep 17, 2007 #12
    Okey, my idea that rotational motion gets transformed into swinging motion was too complicated. The energy comes more probably in the same fashion as it comes to sailboats, but the rotation is still key part of this. The other swings don't get energy out of the wind similarly, because they don't rotate correctly.
     
  14. Sep 18, 2007 #13
    It's most likely a fluke. A combination of disturbances in the flow of the wind along the ground and around the other two swings or the swingset frame. It could also easily be a hoax. Grainy video quality, a lot of people standing around...it'd be very easy to just attach a piece of fishing line to the swing and pull in the same rhythm of a normally-moving swing.
     
  15. Sep 19, 2007 #14
    If you look at the dog in the first closeup (XK74) it doesn't appear to be windy from that angle. Hard to tell with everyone else bundled up.
     
  16. Sep 19, 2007 #15

    DaveC426913

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    If it were a lone swing, and it happened only occasionally and stopped, it wouldn't be weird. But the fact that there are two other swings immediately adjacent that clearly do not behave the same way, and the fact that it occurs quite consistently over what appears to be days or more - is odd.

    Not amazing, but certainly not your textbook behaviour.
     
  17. Sep 19, 2007 #16
    Also, the swing was replaced and the new one showed the same behaviour!
     
  18. Sep 19, 2007 #17
    Well, The city mayor has called a group to "Investigate" the swing, The group is called: "Vision Ovni" (UFO sight!) lol.. Anyway, this is some of the data they have collected:

    They made many wind speed measurements and they say the swing moved under all this wind speeds:

    11,30 hs 2.3 meters/sec
    14,00 hs 2.2 meters/sec
    16,50 hs 1.3 meters/sec
    18,30 hs 2.2 meters/sec
    20,00 hs 2.2 meters/sec

    They also claim to have measured the temperature and there was no difference with it surroundings

    They have measured the magnetic field while the swing was moving and when it was stopped it always was 1.2 mlg (i don't even know what that means)

    Terrain galvanic current: 3 ohms


    http://www.visionovni.com.ar/firmat.htm
     
  19. Sep 19, 2007 #18

    DaveC426913

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    They measured the temp? (rolls eyes). Sounds like they're looking for poltergiests.

    Me, I'd be happy with one test: put up a large wind barrier upwind. If that doesn't stop it in its tracks, I will become very interested.
     
  20. Sep 19, 2007 #19
    Well, they actually claim to have done that! and the swing didn't stop

    But came on, they are an ufo group, and no video for that situation.

    here's the pic: http://www.visionovni.com.ar/firmath8.JPG
     
  21. Sep 21, 2007 #20
    What happens if the swing's shape is changed, by binding it together?

    This can't be debunked by watching a video. Experiments need to be performed. You can't perform the kind of experiments needed to analyze this on a video.
     
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