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Bouncing UK Children Cause Earthquake 221

Posted by timothy
from the up-and-down-simultaneously-sounds-impossible dept.
Xibalba writes: "This is kinda cool. One million children in the UK jumped up and down simultaneously in an attempt to see what would seismically happen." This cries out to become an annual (and international) all-ages event. Bounce! Bounce! Gain weight! Bounce! Repeat.
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Bouncing UK Children Cause Earthquake

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  • See also... (Score:2, Interesting)

    by Cerberus9 (466562) on Saturday September 08, 2001 @01:51AM (#2266427)
    Reminds me of:

    1) the effect when thousands of soldiers crossing a bridge intentionally fall out of step to avoid setting up sympathetic vibrations in the bridge, thus collapsing it (which used to be a real problem before they figured out the cause!)

    2) for the Chinese scanario: instead of having them all jump off a chair in their homes, line them up on the shoreline and have them dive in to the surf simultaneously - possibly setting up a tseunami heading eastward.
  • by Jace of Fuse! (72042) on Saturday September 08, 2001 @02:44AM (#2266491) Homepage
    The kids didn't actually jump simultaneously.

    It wasn't simultaneously, otherwise the effects WOULD have definately been much greater.

    There is a military command (I can't remember the exact order) given in a march that instructs marching soldiers to lose cadance when crossing a bridge. Failure to do so has been known to collapse bridges as the combined force of dozens of troops marching in unison is capable of creating a powerful ressonance.
  • by wowbagger (69688) on Saturday September 08, 2001 @06:40AM (#2266758) Homepage Journal
    There was the experiment that was done in the early days of cellular telephony here in the US. A guy filled a football stadium-sized parking lot with people, loaned them all cell phones, had them dial, and then everybody pressed SEND at the same time. The point he was making was that the cellular system wouldn't handle such an event gracefully.

    It didn't. It crashed not only the local cell site, but several others as well.

    Of course, this is in a microcosmn what happens when there is a big "event" such as an earthquake or bombing - everybody tries to call Aunt Phillis and the cell network goes down. That's when we hams get busy....
  • by HardFocus (87842) on Saturday September 08, 2001 @06:46AM (#2266765) Homepage

    This story reminded me of Tesla's Earthquake machine [primenet.com] which, if you believe the stories, demonstrates just how much damage you can inflict when you hit the resonant frequency with a modest amount of power.

  • Re:See also... (Score:3, Interesting)

    by bazoungus (125200) on Saturday September 08, 2001 @07:02AM (#2266790)
    I suspect the bit about sympathetic vibrations causing a bridge to collapse is mostly an urban legend, at least for modern bridges

    It did happen on April the 16th 1850 in France, when a troop crossed a suspension bridge durong a storm near Angers (the Basse-Chaine bridge, over the river Maine) causing 220 soldiers to drown.

    There's a good sum up of the event here [www.cnam.fr] (in English)

    The cause is supposed to be the addition of gusts of wind causing the bridge to sway, and the troop marching steps, all giving a phenomenon of resonance.

    and it even was reported in the New york Herald at the time :

    http://www.goodbyemag.com/may00/herald-deaths.html [goodbyemag.com] (in English)

    however, the causes are very similar to what happened to the Tacoma Narrows bridge, on nov 07 th 1940, catastrophic wind swaying.

    I'm happy to share this part of my history,

    Baz.
  • by GregWebb (26123) on Saturday September 08, 2001 @07:27AM (#2266836)
    While I've certainly heard of this before, its effectiveness may well be limited.

    Has anyone heard of the Millennium bridge across the Thames in London? Pedestrian suspension bridge, kept in suspension sideways IIRC so no tall pillars or overhead cables. Problem was, it wobbled. It wasn't damped enough so could sway quite noticeably from side to side and was closed. There was then a controlled re-opening for people who knew full well it would wobble. They then realised they were going to have to have squads of staff to break up those maliciously walking in step and so amplifying any forces.

    The problem, though, was that with the bridge wobbling sideways people were inevitably going to try and stabilise themselves so as not to collapse. So, as you feel a wobble sideways you brace yourself against it and so exert a sideways force on the bridge which makes it wobble in that direction... and you get the idea. Everyone quickly falls into step with each other, so amplifying the wobble...

    Spot the problem.
  • by mrv (20506) on Saturday September 08, 2001 @10:52AM (#2267483) Homepage
    Back in the late 1980s/early 1990s, there was a "prediction" that there would be a great earthquake to hit the Mississippi River valley. (I think it was predicted for an intercontinental plate line running near St. Louis.)

    Anyhow, during the week or so of hyped-up media coverage (slow news week?), there were several "Fat is Beautiful"-type groups (and maybe a few weight-loss groups, too, I don't remember) that all decided to stand on the fault line and jump in unison, to get the big earthquake started. The earthquake never happened, but...

That does not compute.

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