Debunking the Ghostly Swing Phenomenon in a Small Town in Argentina

[Ivan Seeking]

Okay, good enough. In the future, please provide sources for any quotes when they are made. I really thought that you were just making this up.

One more note: It sounds like this group could have scientists as members. More likely they are a bunch of crackpots or the story is reported incorrectly, but "UFO researchers" certainly does not automatically translate as "non-scientists". Most of the UFO people that I know or have met personally are Ph.D. scientists.

 

[lazypast]

id say its the same thing that destroyed tacome suspension bridge in 1940 by resonance, which the wind was to blame for that also.
dunno why the other 2 swings don't go though

 

[Nomad]

This is a great example of resonance coupling.

The swing has two periodic components, the (regular pendulum) translational component and the torsional component (rotation about the vertical axis). The wind can cause a swing to move in either mode, but no too much, but when coupled, the effect can become quite large. This is the same phenomenon that brought down the Tacoma Narrows bridge ( ).

If the wind blows through at an angle, it can turn the swing slightly. The key is the fact that as the swing turns, it can catch the cross-blowing wind like a sail, which will give it a shove in its pendular motion. If the twisting motion has the same frequency as the pendulum ( or the two are an integer ratio), then after each pendulum swing, the seat will be in the same torsional position, ready to pick up another boost from the wind. If the two are not in resonance, the wind cannot impart a push at a consistent point in the seat's swing.

Things that can mess this up, and would also distinguish the center seat from the other two, are:
> The lengths of the chains. This would alter the frequency of the pendulum.
> The equlity of the two chain lengths on any given swing (changes the torsional motion)
> The position of the center of mass of the seat. (How "U" shaped it is) This would also alter the pendulum period.
> The stiffness of the seat material. This would alter the torsional period, and also how the seat picks up the wind when oriented a particular way. It would also affect any tensional vibration of the seat (picture the seat as a droopy guitar string - this could potentially play a role in how the seat picks up the wind)

It was unfortunately impossible to determine from just the video how these attributes of the center swing differed from the other two.

I also noticed that there was a depression in the swing area which was centered around the middle swing. This alone could account for the differences in behavior: If the wind were strong enough (and it sounded like it was) air flowing at the edge of the depression would be slightly turned downward or upward, i.e. turbulent, whereas wind going across the center area would be more laminar. This would give a more steady and even air flow across the seat, and thus a more consistent push.
Someone suggested the poles might also play a role. I wouldn't think this would give a real great contribution; however if we are considering turbulence in the airflow, the poles might be just large enough to break the laminar flow of the air for only a short distance after the pole, i.e. to the first swing and not the second or third.