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#1

PY7

    PY7


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Geplaatst op 07 augustus 2008 - 20:16

Ik kwam daarnet dit tegen op wikipedia. Er staat in dat fulguriet meestal hol is.

En ik vraag me nu dus af; Waarom is dat zo? En waar is al die materie die daarbinnen zat naartoe?

Ik zou juist denken dat die buis helemaal toesmelt als gevolg van de hoge temperatuur, maar blijkbaar dus niet. :D

Heeft iemand een passende verklaring?

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#2

Jan van de Velde

    Jan van de Velde


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Geplaatst op 07 augustus 2008 - 22:35

http://www.minsocam....njfulgurite.htm
(link gevonden onder het engelse wiki-lemma fulgurite)

Much room is left for conjecture concerning the mechanics of the formation of a fulgurite. A bed of sand with its comparatively uniform mineral composition and corresponding uniform electrical resistance, composed largely of one mineral readily fusible at the temperature attained, presents ideal conditions. At least fulgurites from other sources are rare, although a similar phenomena caused by lightning striking rocks has been reported. The tube-like structure may be due in part to the sudden cooling which must have been rapid or glass would not have resulted. It may also be due to the fact that the volume of sand which was fused to glass must have been much greater than the volume of the resultant glass, leaving a crude cylindrical mould to whose sides the glass was drawn by cohesion while in a viscous state. The included bubbles have most probably arisen from moisture entrapped during the sudden fusion of the sand, wet from the storm, or perhaps in part from volatilization of silica or other components into a gaseous form when the bolt struck. The presence of mullite is undoubtedly due to the short time the mass was liquid, thus giving the alumina of the clay insufficient opportunity to be thoroughly disseminated through the silica glass for complete solution. Hence, at points of high local concentration of alumina, mullite was formed.


http://www.usfcam.us...s/03.Copper.pdf

Artificial fulgurites have been noted in sand, from a locality
also in Riverside County2. At this place, a 16,500-volt power
line broke, and because of a faulty safety switch, current flowed
for some time into the sand before it was shut off. This produced
artificial conventional fulgurites, except that the artificial
fulgurites tended to be solid rather than hollow tubes, probably
because of continuous rather than intermittent discharge
of the electricity.


De verklaring van de enorm hoge temperatuur in het bliksemkanaal (vorming van damp/gassen onder hoge druk) in combinatie met snelle afkoeling lijkt me wel wat. Een soort van natuurlijk glasblazen eigenlijk.
ALS WIJ JE GEHOLPEN HEBBEN....
help ons dan eiwitten vouwen, en help mee ziekten als kanker en zo te bestrijden in de vrije tijd van je chip...
http://www.wetenscha...showtopic=59270





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