Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Plastic thing that will spin only one way? Wtf?

  1. Jul 23, 2007 #1
    Plastic thing that will spin only one way!? Wtf?

    Has anyone a clue how this works???

    In the video, the guy demonstrates a piece of plastic that will spin only one way. Just look at the video, you will see what I mean. It's really impressive, and I must know how it works!!

    It's at about 4 minutes into the video.

    Link deleted: Ivan
     
    Last edited by a moderator: Jul 23, 2007
  2. jcsd
  3. Jul 23, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    The Amazing Rattleback!

    That toy is called a rattleback--they've been around forever. Pretty cool, eh? The physics is complicated. Check this out for a taste: The Amazing Rattleback!

    By the way, that video is full of wild crackpottery and nonsense. Don't waste your time with it.
     
  4. Jul 23, 2007 #3

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That is called a rattleback and it is well understood.
    http://physicscourses.okstate.edu/ackerson/museum/Rattleback.htm

    The link in the op has been deleted since the material within violates the posting guidelines.

    Edit: Whoa! Doc Al is fast on the keys today. :biggrin:
     
  5. Jul 23, 2007 #4
    damn that was tite, i love scienceee!
     
  6. Jul 23, 2007 #5
    Well that was cool!

    Indeed, apologies for the link. I am interested in the study of UFOs, and came across the video but I have lost respect for David Sereda now. I admired his study on UFOs before, but he was so amazed and taken back by such known physics (even the induction one) , and he supposedly has a degree in physics.
     
  7. Jul 23, 2007 #6

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That's okay. We do discuss specific UFO events. and we consider the evidence - anecdotal and otherwise - for those events, but we don't get into exotic theories [ET] in order to explain them. We all know that many people claim that ET is here, but without proof of this claim, that's about as far as we go on that point - we recognize that the claim exists. The Hutchison stuff is a banned topic altogether. The rest of what I heard on that link was nonsense as well.

    I've been following the UFO enigma for over two decades. I'll let you know when I know what to think of it all. However the rattleback is explained, and it doesn't require nuclear physics as was seemingly suggested in the video. :biggrin:
     
    Last edited: Jul 23, 2007
  8. Jul 24, 2007 #7

    J77

    User Avatar

    If you're interested in cool geometries -- tho with rocking, not spinning -- check this out: http://www.gomboc.eu/
     
  9. Jul 25, 2007 #8

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Not by me or most students I've shown it to :rolleyes:
     
  10. Jul 27, 2007 #9
    Yeah , its a classical physics toy ...ask in the classical physics section they'll tell you.
     
  11. Jul 27, 2007 #10

    DaveC426913

    User Avatar
    Gold Member

    I saw this just the other day. The curve that it rocks on is not symmetical; it is slightly more curved in one direction than the other. Momentum is conserved in both directions of rotation, but the period of the rocking, while smooth in one direction, sets up a destructive rocking in the other direction (sort of like what happens before you get a skipping rope up to speed).

    From Wiki:

     
    Last edited: Jul 27, 2007
  12. Jul 27, 2007 #11

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    I know (on paper) how it works - it was the statement that it was 'well understood' that was slightly ironic.

    A bit like Hardy allegedly stopping in the middle of a proof in a lecture, doing 2 hours of frantic calculation, and continuing with "yes, it is obvious that...."
     
  13. Jul 30, 2007 #12
    So this thing would pretty much spin normally on a frictionless surface, right?
     
  14. Jul 30, 2007 #13

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Yes. This is from the link that I posted.

     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Plastic thing that will spin only one way? Wtf?
  1. What is the one thing (Replies: 23)

Loading...