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Physicists Finally Solve the Falling-Paper Problem

Posted by michael on from the falling-down dept.

neutron_p writes "The so-called "falling paper" problem has long intrigued scientists. James C. Maxwell pondered the tumbling motions of playing cards in 1853. Why don't flat things fall straight down? Pieces of paper fall down, then rise into the air, then glide along, then again rise... It occurs in a seemingly chaotic manner. Now researchers at Cornell University have solved the falling paper problem by calculating the motions of a scientific journal page in flight and there were a few surprises." There's also a story in the Cornell Sun.

13 of 325 comments (clear)

  1. That's my prof! by beefstu01 · · Score: 4, Interesting

    Prof. Wang from TaM was my math teacher. Smart lady. She went crazy explaning the use of hyperbolic trig functions. At the time I had no idea what she was talking about, but now I see it actually has a use. Her other research is in the fields of insect flight. Looks like Calculus isn't useless after all.

  2. Usefulness by ornil · · Score: 5, Interesting

    The article says that the slowing-down effect for paper-like objects is much larger than normal "parachuting" effect. I wonder if this could be used in some way for parachutes.

    1. Re:Usefulness by 3770 · · Score: 2, Interesting

      You are thinking about the first possible application which would be to somehow attach yourself to one huge piece of flat material and somehow use that to slow your fall.

      But if you on the other hand had a parachute which somehow was made up of thousands or maybe millions of small pieces of flat objects which could rotate independently you might achieve the same effect, and the random falls would average out.

      It is also reasonable to believe that the smaller the object the smaller the random drops.

      My imagined parachute above might not work. But can you prove it? It shows that there are applications of this which we might not fully understand after reading an article on the Internet.

      But then again, maybe you already thought about this and was just making a joke.

      --
      The Internet is full. Go Away!!!
    2. Re:Usefulness by ajna · · Score: 4, Interesting
      if you on the other hand had a parachute which somehow was made up of thousands or maybe millions of small pieces of flat objects which could rotate independently

      Again your caveat about not fully understanding the issues involved after reading a single non-technical article applies, but I got the impression that the phenomenon requires rotational and translational motion to be decoupled. Thus rotating independently may well be insufficient to allow for the effect of falling slower than via "parachuting".
  3. Re:Yup by discordja · · Score: 5, Interesting

    Okay
    http://www.sciencenewsforkids.org/pages/puzzlezone /muse/muse0704.asp

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    I stole this .sig
  4. Re:rolloverrover by slaad · · Score: 2, Interesting

    This might be useful for future Rover missions (or, um Beagle missions). You'll lose accuracy, but at least you wouldn't hit the ground like a falling rock.

    Or maybe for falling capsules...(just in case someone plugs something in upside down)

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    ~Warning!~ The above is encrypted using rot676!
  5. They do fall straight down... by Anonymous Coward · · Score: 4, Interesting

    If you're on the moon, where there is little or no atmosphere, they will fall straight down. Has anyone seen the video of the feather falling straight down without fluttering around at all?

    1. Re:They do fall straight down... by kasperd · · Score: 2, Interesting

      Has anyone seen the video of the feather falling straight down without fluttering around at all?

      I have actually seen the real thing. In connection with our faculty there is a small museum. Among other things they have two vacuum tubes that can be turned upside down. In one there is a feather in the other there is a stone. Interesting to see them fall at exactly the same speed.

      --

      Do you care about the security of your wireless mouse?
  6. I'm surprised at what surprised these guys... by Anonymous Coward · · Score: 5, Interesting

    "There were a few surprises," Wang notes. "We found the flat paper rises on its own as it falls, which would not happen if the force due to air is similar to that on an airfoil. Instead, the force depends strongly on the coupling between the rotating and translational motions of the object."

    Anyone who has ever thrown playing cards, frisbee, venetian blind bomerang (you have to be old enough to have had wooden venetian blinds as a kid) would not be surprised at the quoted 'surprise'.

  7. Re:Once again, I will remind the scientific commun by imsabbel · · Score: 2, Interesting

    What are you doing for a better world today?
    How about selling your computer and feed some children in nigeria with the money?
    Would have the nice side-effect that we wouldnt have to hear your wise-ass remarks.

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    HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
  8. Re:Advanced Mathematics by Anonymous Coward · · Score: 2, Interesting

    Smartass teachers like to give students tasks they think are impossible and offer bonus points. I'm sure for 85 dollars and gold foil, it was something like a free A in the class. When I was in eighth grade a teacher offered a A for the class if you memorized a few hundred digits of pi that were posted circleing the room near the ceiling. I wish I had know about Pseudonumbers then. I probably wouldn't have learned any algebra after that, but I would've shown that smartass.

  9. Re:Scientests figure out how paper falls. by mdfst13 · · Score: 4, Interesting

    "If we took the money that the physicists receive"

    There is no evidence that the physicist and the mathematician received any extra money here. They probably are both lecturers (someone already posted about having the mathematician for a class). They may well be doing the research part in their free time. If you have a problem with that, maybe you should stop reading /. in *your* free time and get to work on that cure for cancer.

    For that matter, why aren't you criticizing smokers? Not only do they make themselves more likely to get cancer, they also take frequent breaks to smoke. I wouldn't be at all surprised to find out that smoke breaks take more time than the sum total of cancer research. Eliminating smoking would free up physicians who are currently working on cancer to do research and provide more time for non-physicians to do maid work, etc. to free up physicians to concentrate on their cancer research.

    The results of physics research also free up people by cutting costs in other areas. If we still had a hunter/gatherer economy, we wouldn't be able to waste people on non-essentials like medicine, much less medical *research*. Not to mention the point that the advances in understanding chaotic systems may be applicable in areas other than physics (e.g. medicine). While statistical analysis (from mathematics!) suggests possible causes of cancer, we still don't understand what actually happens.

  10. Note Air Force involvement by marbux · · Score: 3, Interesting
    The U.S. military have a longstanding interest in the dynamics of falling pieces of paper and did extensive research on the topic in arriving at the ideal dimensions for propaganda leaflets dropped from aircraft and leaflet bombs that would provide reasonable assurances that the leaflets hit the intended target.

    I served in an Army psychological warfare unit in Viet Nam that had produced and delivered, by 1970, enough leaflets to cover the entire country of South Viet Nam to a depth of more than 6 inches. Delivery was divided between Army helicopters and Air Force planes.

    It's not surprising to see the Air Force funding further study on this subject.