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THE FORUM
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20-Apr-23, 06:13:18 AM
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316
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Anything Else / Totally OT / Re: 32 out-of-sync metronomes synchronize with each other by themselves
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on: 27-Sep-12, 10:26:16 PM
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Notice that the "bridge" beneath the metronomes is oscillating in time with them. This is why soldiers break cadence when marching across a bridge.
I've heard about that, with soldiers; it was explained as having something to do with a frequency that mechanically resonated with the bridge and could make it fall. Does that make sense? I'm wondering in this case if some fuzzy initial majority tendency got the table moving in a way that influenced more and more of them? In other words, maybe it happened because of a subtle movement of the table?
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321
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Other Nature Related Information / General Nature Discussion / chasing ice
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on: 05-Sep-12, 10:04:35 AM
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cousin Paula's new film - the trailer http://www.chasingice.com/Huffington Post: http://www.huffingtonpost.com/2012/09/04/chasing-ice-trailer-james-balog_n_1852839.html"I never imagined that you could see glaciers this big, disappearing in such a short time. There's a powerful piece of history that's unfolding in these pictures," National Geographic photographer James Balog describes in the new "Chasing Ice" trailer. "Chasing Ice" follows Balog's journey as he works to capture the fast-vanishing Arctic glaciers. Armed with 30 time-lapse cameras on three continents, Balog and his team compress years of video footage into seconds to reveal the disappearance of mountains of ice. As director and founder of the Extreme Ice Survey (EIS), Balog's long-term photographic study of glaciers examines the effects of global climate change on landscapes. Through his work, he has witnessed the changing planet firsthand. The National Snow and Ice Data Center recently reported that the extent of Arctic sea ice melted to record lows the summer. Data center scientist Ted Scambos told the Associated Press that global warming from man-made emissions of greenhouse gases is mostly to blame. As Balog describes, gesturing to his film, "This is the memory of the landscape. That landscape is gone; it may never be seen again in the history of civilization. And it's stored right here." The film "Chasing Ice" opens in New York City on November 9, theatrically November 16.
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322
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Other Nature Related Information / General Nature Discussion / spider ballooning
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on: 03-Sep-12, 12:31:52 AM
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From Wikipedia
Ballooning is a term used for the mechanical kiting that many spiders, especially small species, as well as certain mites and some caterpillars use to disperse through the air. Many small spiders use gossamer or especially fine silk to lift themselves off a surface or use the silk as an anchor in mid air. The very fine silk used for ballooning has been called "gossamer" since 1325 and was not originally known to be produced by spiders; by extension, the same word is used metaphorically for any exceedingly fine thread or fabric. Biologists also apply the term "balloon silk" to the threads that mechanically lift and drag systems.
A spider or spiderling after hatching will climb as high as it can. The spider then stands on raised legs with its abdomen pointed upwards. This is known as "tiptoeing". After that, it starts releasing several silk threads from its abdomen into the air, which automatically form a triangular shaped parachute. The spider can then let itself be carried away by updrafts of winds, where even the slightest of breeze will do. Most rides will end a few metres later, or a spider can be taken up into a jet stream, which depends on its mass, posture, the convection air current, drag of silk and parachute to float and travel high up into the upper atmosphere. Many sailors have reported spiders being caught in their ship's sails, over 1600 km from land. They have even been detected in atmospheric data balloons collecting air samples at slightly less than 5 km (16000 ft) above sea level. Evidently it is the most common way for spiders to invade isolated islands and mountaintops. Spiderlings are known to survive without food travelling in air currents of jet streams for 25 days or longer.
It is generally thought that most spiders heavier than 1 mg are not likely to use ballooning. Also, because many individuals die during ballooning, it is more unlikely that adults will do it than spiderlings. Adult females of several social Stegodyphus species (S. dumicola and S. mimosarum), weighing more than 100 mg and with a body size of up to 14 mm, have, however, been observed ballooning using rising thermals on hot days without wind. These spiders use tens to hundreds of silk strands, which form a triangular sheet with a length and width of about 1 m.
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323
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Member Activities / Birthdays / Re: HAPPY BIRTHDAY DALE!
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on: 19-Aug-12, 09:47:42 AM
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thank you SO VERY much, everyone, for the kind wishes!!
(I had a rare non-internet day, which explains my tardy response)
wishing you all health and happiness as well!
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