1. Mick West

    Mick West Administrator Staff Member

    Manchester Museum is getting a lot of publicity for a video of a statue that slowly rotates through the course of the day. It's on a glass shelf, and it only moves when there are people walking nearby.

    [​IMG]

    This raises the obvious suggestion that the rotation is simply due to the vibration. The statue is hard uneven stone, and the glass shelf is very hard and perfectly flat. When two hard substances are in contact with each other, then there's not much friction because there are limited points of contact. I suspect that the base of the statue is uneven, which allows it to tilt and pivot very slightly from the vertical vibration from people walking by. The shelf is very slightly tilted towards the front, so the statue rotates until the center of gravity is at the lowest point, and then it stops.

    Firstly the issue of object moving on a glass shelf visitor induced vibration from wooden floors is a known problem in the museum industry, see:
    http://www.english-heritage.org.uk/content/imported-docs/u-z/vibration-rio.pdf


    To test this theory out, I made a functional replica of the situation using a glass table, a piece of wood with some screws in for the hard uneven base, and a container of salt for the statue.

    [​IMG]

    (Skip to 0:35 in the following video to see the experiment)



    Initial tests showed that the movement and rotation of the statue varied a lot based on the geometry of the base - i.e. the relative height of the screws. Adjusting one screw a fraction of a turn could entirely change the behavior. So it's pretty random that the statue ended up moving the way it did.

    As I did not have lots of people to walk around my table for days I accelerated the process by angling the table probably slightly more than the shelf (it's still only 2 degrees though), and by directly vibrating the table. This is obviously not the same as what happened - the magnitudes are different, but the concept is the same.

    [​IMG]

    [​IMG]


    Some inevitable questions:

    Why has it never moved before?
    Firstly its obvious that that it's not been on that exact same shelf for "decades" or "80 years" as some news stories report. In fact that's the new Ancient World Gallery, which opened around Oct 2012), so it's been there for a few months at most. The curator simply said it had been on a similar shelf before.
    Secondly, experiments show the motion is dependent on circumstances. So something must have changed, but only very slightly - the slope of the shelf, the position of the statue on the shelf, even the position of other objects can affect the vibration. Even a very slight shift in the frame of the building could be responsible.
    And perhaps the previous curators had been sensible, and secured it to the shelf with a dot of wax.

    Why are the other statues not moving?
    Because they are different. They are smaller, they are shorter, they have a more centered center of gravity, they are made of different materials, they have different bases, they are in different positions.

    Why does it spin exactly 180 degrees?
    Because the shelf is sloped very slightly down towards the front of the cabinet, so it stops when the center of gravity gets to the lowest position.

    Why does it go round in a circle?
    Because it's pivoting on a point in the base. In my experiment this is represented by the center screw, which is just a tiny bit more protruding than the others. But the actual geometry will vary.

    Why does it rotate so slowly when yours goes so fast?
    Because of the magnitudes of things. The vibration is less in amplitude, the pivoting on the base is smaller, the slope is less. So it's doing to very large number of much smaller motions.

    What about:
    A) The museum employees was working in the gallery, so perhaps they caused the vibration themselves
    B) Vibrations could come from people in other rooms, or upstairs.
    Last edited: Nov 20, 2013
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  2. Mick West

    Mick West Administrator Staff Member

    Some more instances of "Walking" in museum literature

    http://www.gastoncountymuseum.org/ceramic.asp

    http://aics41stannualmeeting2013.sched.org/event/e434a19c8d27b291d60a12fa10d96bb2#.Uceo2z6wzow

    http://www.britishmuseum.org/csrmellonpdfs/FR1999-6_u.pdf
  3. Soulfly

    Soulfly Senior Member

  4. Joe

    Joe Active Member

    • Like Like x 2
  5. gwenlock

    gwenlock New Member

    I think the explanation is much more simple. I read one article that said the "video" was a series of photos taken one minute apart. Notice the second counter doesn't move in the "video". They are moving the damn thing in between shots.
  6. Mick West

    Mick West Administrator Staff Member

    I think that's a much more complicated explanation actually. Occam and all. Things walking on shelves is a known occurrence. Adding a bunch of people faking the movement in full view of museum guests, at a perfectly smooth rate, and nobody noticing, - that just introduces too many additional things.
  7. David Fraser

    David Fraser Senior Member

    I know the museum quite well as the kids used to visit the vivarium. That section has wooden flooring throughout and it does feel springy in parts (trust be with 5 kids in a museum you learn to tred softly) Also it is on the Oxford Road side of the museum with the road been say 30 or 40ft away. Given the busy traffic, especially double deckers, one would expect even a minute amount of vibration.
  8. Mick West

    Mick West Administrator Staff Member

    I graduate in the building next door, some years ago.

    [​IMG]
    Last edited: Nov 20, 2013
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  9. David Fraser

    David Fraser Senior Member

    That's not bad for an Autochrome photograph;-)
    Last edited by a moderator: Nov 20, 2013
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  10. JFDee

    JFDee Senior Member

    Once more, the crave for limelight sweeps away all self-restriction imposed by science ...

    I believe the curators and scientists mean well, trying to increase visitor figures and stoking interest in their subject, competing with today's entertainment culture.
    The problem is that what sticks in the end may contribute to the erosion of scientific thinking, becoming itself part of the entertainment cycle.

    I sincerely hope that Metabunk's "early debunking" can mitigate this process.
  11. Mark

    Mark New Member

    " This is obviously not the same as what happened - the magnitudes are different, but the concept is the same."

    Differences! Enough said. You are NOT convincing Sir. Especially given that nothing else ever moved a single, measly millimeter!!!!!

    I love all these DEBUNKING sites. You guys crack me up with your lack of horizon and scientific dogma you are suffering from.


    Byes.
  12. JFDee

    JFDee Senior Member

    The other pieces on that shelf are obviously very different, especially regarding the center of gravity. So why should they not behave differently? It may also be that their base is more even, thus increasing friction.

    If you have a more reasonable explanation, I should like to hear it.
    • Like Like x 1
  13. Vinncent

    Vinncent New Member

    Did you even read through Mick's analysis?

    I was skeptical both of the initial "magic movie statue", and was also skeptical that mere minor vibrations could move such a large, heavy object... however, as others have pointed out, this is a fairly regular phenomena that museums around the world have noticed, and usually take measures to counteract (such as the wax dot thing).

    It seems reasonable that some source of vibration, whether it be from visitors, staff, or aspects of the building such as air conditioning units, fans, etc... are in total enough to move an object on a near-frictionless plane with a low point of contact. The fact that it always stops in the same position also supports this theory.

    What doesn't seem like a reasonable explanation is the museum is haunted by ghosts.
    • Like Like x 1
  14. Rodrigo M Pereira

    Rodrigo M Pereira New Member

    is about vibration, but not about people around.

    I saw something happening like that in a store. We realized that the vibration was coming from the street. The have traffic of trucks, buses and cars were doing enough vibration to make glasses moving after some hours.

    :)
  15. Mick West

    Mick West Administrator Staff Member

    Extensive research has confirmed my kitchen table experiment :)

    http://www.bbc.co.uk/news/uk-england-manchester-25005916
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  16. gwenlock

    gwenlock New Member

    Honestly, as a former magician, I really really don't think it's as complicated as all that. The video has gaps. Someone probably just turning it every minute or so as the video stops and restarting the video. I know first hand that magicians and all manner of charlatans have no qualms doing the most devious and simple thing possible. Publicity. Occam's razor is that the most SIMPLE explanation is the most probable.
  17. Mick West

    Mick West Administrator Staff Member

    No it isn't, Occam's razor says don't add new things when existing things already explain it. We know that vibration can move things. We know that there was vibration. Tests now confirm it. Case closed.
  18. WillofLa

    WillofLa New Member

    I've seen this video. What you seem to be missing is the fact that the statue does not rotate during the day, only at night. I think you need to watch it again.
    • Funny Funny x 1
  19. Mick West

    Mick West Administrator Staff Member

    I think you have that backwards. It's largely rotating when there are people in the room.

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