As i was re-posting the latest UK ratings one of the University buildings
was struck by lightning - propbably the one next door to where i work
[cries of: "serve you right for not posting earlier, you lazy old
bastard!" from the UK VTES community]. i know this because i heard the
flash earthing [loud electrical click], followed by a massive clap of
thunder, and car-alarms going off. About two minutes later the emergency
vehicles arrived so i hope no-one has been hurt - it isn't a fire alarm,
i'm sure of that. Anyway the interesting point is that despite being no
more than 50 yards from the point of impact, there WAS a noticeable delay
between the strike and the associated thunder - half a second, maybe. i
reckon sound travels a bit less than 1200 ft/sec, so i guess that means
that the sound you hear actually comes from above. But it looks to me
that the clouds are well over 1000 feet above, so it's not the sound of
two clouds clapping like i was taught by my thoroughly-mendacious
geography teachers. Any climatological gurus on the NG care to enlighten
my secondary-school level darkness about what, exactly, thunder IS?
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
legb...@my-deja.com wrote:
>i'm sure of that. Anyway the interesting point is that despite being no
>more than 50 yards from the point of impact, there WAS a noticeable delay
>between the strike and the associated thunder - half a second, maybe. i
>reckon sound travels a bit less than 1200 ft/sec, so i guess that means
>that the sound you hear actually comes from above. But it looks to me
>that the clouds are well over 1000 feet above, so it's not the sound of
>two clouds clapping like i was taught by my thoroughly-mendacious
>geography teachers. Any climatological gurus on the NG care to enlighten
>my secondary-school level darkness about what, exactly, thunder IS?
Air, heated by the lightning strike, expands rapidly, causing the
sound waves that make up thunder (a sonic boom).
More info:
http://www.weather.com/breaking_weather/encyclopedia/thunder/boom.htmlhttp://nantahalapower.com/thunder.html
--
L. Scott Johnson (sjoh...@math.sc.edu) |
http://www.math.sc.edu/~sjohnson | Oxymoron: Microsoft Works
Graphics Specialist and V:TES Rulemonger |
L. Scott Johnson <sjoh...@math.sc.edu> wrote in message
news:37E8F7AB...@math.sc.edu...
> legb...@my-deja.com wrote:
> >i'm sure of that. Anyway the interesting point is that despite being no
> >more than 50 yards from the point of impact, there WAS a noticeable delay
> >between the strike and the associated thunder - half a second, maybe. i
> >reckon sound travels a bit less than 1200 ft/sec, so i guess that means
> >that the sound you hear actually comes from above. But it looks to me
> >that the clouds are well over 1000 feet above, so it's not the sound of
> >two clouds clapping like i was taught by my thoroughly-mendacious
> >geography teachers. Any climatological gurus on the NG care to enlighten
> >my secondary-school level darkness about what, exactly, thunder IS?
>
> Air, heated by the lightning strike, expands rapidly, causing the
> sound waves that make up thunder (a sonic boom).
I thought it was one of Thor's goats. You know the ones he keeps eating.
--
Conor
Prince of Raleigh
[ quoted text not captured ]
In article <7sbkev$sid$1...@nntp6.atl.mindspring.net>, "Celt"
<tirn...@mindspring.com> wrote:
> L. Scott Johnson <sjoh...@math.sc.edu> wrote in message
> news:37E8F7AB...@math.sc.edu...
> > legb...@my-deja.com wrote:
> > >i'm sure of that. Anyway the interesting point is that despite being no
> > >more than 50 yards from the point of impact, there WAS a noticeable delay
> > >between the strike and the associated thunder - half a second, maybe. i
> > >reckon sound travels a bit less than 1200 ft/sec, so i guess that means
> > >that the sound you hear actually comes from above. But it looks to me
> > >that the clouds are well over 1000 feet above, so it's not the sound of
> > >two clouds clapping like i was taught by my thoroughly-mendacious
> > >geography teachers. Any climatological gurus on the NG care to enlighten
> > >my secondary-school level darkness about what, exactly, thunder IS?
> >
> > Air, heated by the lightning strike, expands rapidly, causing the
> > sound waves that make up thunder (a sonic boom).
Really!
It is correct that the lighting arrives with a "crack" sound closly
followed by thunder, but they are not connected. The thunder comes from
the cloud and the lightning crack from the lightning. I have had the
awning above me struck and been in a vehicle that has been struck and the
second time I had oppertunity to place my fingers in my ears as a reaction
to the lightning strike before the thunder arrived. You know how loud the
thunder is if it has happened to you. I suppose you could call them
lightning reflexes.
--
You will pay for you sins Michael F. Tomkins
m.to...@student.canberra.edu.au
If you have already paided University of Canberra, Australia.
Please disregard this notice http://blitzen.canberra.edu.au/~bahkyp/
On Thu, 23 Sep 1999 12:42:57 +1000, m.to...@student.canberra.edu.au
(Michael F. Tomkins) wrote:
>> L. Scott Johnson <sjoh...@math.sc.edu> wrote in message
>> news:37E8F7AB...@math.sc.edu...>> > Air, heated by the lightning strike, expands rapidly, causing the
>> > sound waves that make up thunder (a sonic boom).>
>Really!
really.
>It is correct that the lighting arrives with a "crack" sound closly
>followed by thunder, but they are not connected. The thunder comes from
>the cloud and the lightning crack from the lightning. I have had the
No, really, what he said IS correct. The delay you hear between the
lightning and thunder is related to both distance from the strike and
time it takes the air to expand. Factual Scientific Proof and all.
>awning above me struck and been in a vehicle that has been struck and the
>second time I had oppertunity to place my fingers in my ears as a reaction
>to the lightning strike before the thunder arrived. You know how loud the
>thunder is if it has happened to you. I suppose you could call them
>lightning reflexes.
If a car you were in had been struck, (a) it would have totally ceased
to operate, and (b) you would have been Crispy Fried Kindred. It may
just have SOUNDED like you were struck, or perhaps it hit directly
across a hill in front of you, but when lightning really hits anywhere
near you, the thunder is near-instantaneous. You certainly wouldn't
have had time to put your fingers in your ears, much less do anything
more than flinch.
Ask the Michiganders. =) They know - they get wacky weather ALL the
time. (and call it "Lake Effect.") =)
-- Derek
(replying by email? remove the nospam from my domain :)
[ quoted text not captured ]
Almost right there. A car is safe and you will not be a crispy critter
when its has been struck by lightning. A car is well grounded by its
tires, but it willhold a rather large static charge. If the vehicle had
been struck and you stepped out just after that, you probably would have
been knock to the ground. Not hurt, just scared s**tless.
As for the electrical system on your vehicle. All I can say is it
depends. Sometime things work just fine, some times the whole system
crashes.
Raille
from SW Michigan, the Lightning State
>L. Scott Johnson <sjoh...@math.sc.edu> wrote in message
>news:37E8F7AB...@math.sc.edu...>> Air, heated by the lightning strike, expands rapidly, causing the
>> sound waves that make up thunder (a sonic boom).>
Hey =) Who knew he was the WeatherMonger, too? I'm getting all my errata
to the function of the Universe from this here NG from now on <grin>
Regards,
R. David Zopf
Atom Weaver (& V:EKN Prince of Charlotte, NC)
On Thu, 23 Sep 1999 09:26:50 -0400, Raille <rai...@mich.com> wrote:
>Derek S. Ray wrote:>>
>> If a car you were in had been struck, (a) it would have totally ceased
>> to operate, and (b) you would have been Crispy Fried Kindred. It may
>> just have SOUNDED like you were struck, or perhaps it hit directly
>> across a hill in front of you, but when lightning really hits anywhere
>> near you, the thunder is near-instantaneous. You certainly wouldn't
>> have had time to put your fingers in your ears, much less do anything
>> more than flinch.
>>
>> Ask the Michiganders. =) They know - they get wacky weather ALL the
>> time. (and call it "Lake Effect.") =)
>>
>> -- Derek>
>Almost right there. A car is safe and you will not be a crispy critter
>when its has been struck by lightning. A car is well grounded by its
>tires, but it willhold a rather large static charge. If the vehicle had
>been struck and you stepped out just after that, you probably would have
>been knock to the ground. Not hurt, just scared s**tless.
Well, actually, some people have survived direct lightning strikes,
too, so perhaps not completely crispy. But I'd think that it would
also conduct through the frame to you, inside, if you touched
anything.
>As for the electrical system on your vehicle. All I can say is it
>depends. Sometime things work just fine, some times the whole system
>crashes.
Heh. More modern cars, more electrical stuff, more computers. I'd
expect a good big "foom".
Volkswagens, on the other hand, might not even notice.
>Raille
>from SW Michigan, the Lightning State
where exactly? i lived in Grand Rapids a long time... and you forgot
to include the Tornado Corner, the Twelve-Inches-in-Four-Hours state,
the Mistaken-Weatherman assumption... Which was actually a great shock
to me when I moved down to Atlanta. I had been used to taking the
weatherman with a grain of salt and relying on looking out my window
to see what the weather would be like - it was literally culture shock
to move here and find people making plans for the weekend on Wednesday
based on what the weatherman was saying... and having him be right!
[ quoted text not captured ]
In article <37EA2A...@mich.com>, Raille <rai...@mich.com> wrote:
> Almost right there. A car is safe and you will not be a crispy critter
> when its has been struck by lightning. A car is well grounded by its
> tires, but it willhold a rather large static charge. If the vehicle had
> been struck and you stepped out just after that, you probably would have
> been knock to the ground. Not hurt, just scared s**tless.
>> As for the electrical system on your vehicle. All I can say is it
> depends. Sometime things work just fine, some times the whole system
> crashes.
>> Raille
> from SW Michigan, the Lightning State
Umm, we are seeing so many theories put forth here I am hesitant to
enter the fray, but I think the insulation provided by your tires is
worthless when you consider the voltages of lightning. It just arced
across hundreds/thousands of feet of air- the 6 inches between your car
and the ground don't matter much, tires or not. Cars are safe because
the electricity flows around the outside of the car (it being a nice
conducting surface) rather than through it- so if you are inside the
car, you won't get hurt. Not because the car is safe, but because the
_inside_ of the car is safe.
I have no clue if the cars electircal systems would survive. I tend to
doubt it, but can't make a useful comment.
ObJyhad: Can elysium be used to avoid weather control damage? Is there
an order of resolution for "before range" effects? I know in general
effects are "as soon as the card is played" but I can easily see that
becoming an issue if a FOR thaum vampire gets blocked by a prey with
the elysium. They need to end the combat before the dawn op/weather
control combo goes off...
Kevin
In article <9FDD370C187C82A9.EA87C375...@lp.airnews.net>,
Derek S. Ray <lor...@nospam.nineball.org> wrote:
>Well, actually, some people have survived direct lightning strikes,
>too, so perhaps not completely crispy. But I'd think that it would
>also conduct through the frame to you, inside, if you touched
>anything.
By my understanding of physics it wouldn't. Since the car isn't grounded,
the electricty won't "want" to go into the car at all. Similar effect
to what happens with downed power lines, or to lightning striking
an aircraft. Essentially the same principle as a Farady Cage...
Then again, I don't trust my knowledge enough to go out and test it. ;-)
--
/\ Jasper Phillips
/VVVVVVVVVVVVVV|~"~"~"~"~"~"----------........____ jaz
j^^^^^^^^^^^^^\/"~"~"~"~-----------........._____ ~"~--.
* http://www.engr.orst.edu/~philljas/ "~"~'--`
In article <7sedne$75b$1...@news.NERO.NET>,
Jasper Phillips <phil...@flop.ENGR.ORST.EDU> wrote:
>
>By my understanding of physics it wouldn't. Since the car isn't grounded,
>the electricty won't "want" to go into the car at all. Similar effect
>to what happens with downed power lines, or to lightning striking
>an aircraft. Essentially the same principle as a Farady Cage...
>
>Then again, I don't trust my knowledge enough to go out and test it. ;-)
Yah, for example, cars are insulated enough to protect against
downed powerlines, but not for lightning strikes. There, it's the
Faraday Cage aspect that saves you. I've still probably got it
wrong somehow.
Anyway, I wouldn't think that touching the frame would matter much, as
it's more conductive than a person. Perhaps if you touched it in
2 places at once though?
[ quoted text not captured ]
In article <7sddi2$5oe$1...@nntp9.atl.mindspring.net>,
"Richard Zopf" <guenh...@mindspring.com> wrote:
> >L. Scott Johnson <sjoh...@math.sc.edu> wrote in message
> >news:37E8F7AB...@math.sc.edu...
>
> >> Air, heated by the lightning strike, expands rapidly, causing the
> >> sound waves that make up thunder (a sonic boom).
> >
> Hey =) Who knew he was the WeatherMonger, too?
Ah, but as your own Woody Guthrie so movingly put it, "You don't have to
be a Weatherman/To tell which way the wind blows" [hmmm ... or was it Bob
Dylan?]
I'm getting all my errata
> to the function of the Universe from this here NG from now on <grin>
>
> Regards,
> R. David Zopf
> Atom Weaver (& V:EKN Prince of Charlotte, NC)
>
Hehehe ... i reckon that you need at least Two Brains to play Jyhad, so
there's a reasonable chance that someone on this NG knows the answer to
pretty much any question you can come up with, and that's why i asked!
It turns out from the local Ceefax news that it was actually the Public
Records Office that was struck, twice in fact. That's about 100 yards
from where i'm sitting, and now that i know what thunder is, the delay is
nicely accounted for. A small fire WAS started, but the staff put it out
themselves before the fire engines arrived - no-one was hurt, thank
Caine.
Now i'm worried about the crispy fried car-inmate business. i was always
taught in Physics that a car acted like a Faraday cage, so you were safe
inside. Of all my secondary school teachers the least mendacious were the
historians and Physicists, so i'm kinda reluctant to accept that they
deceived me on this.
Legbiter, working inter alia on the very disease that killed Woodie
Guthrie [Huntington's chorea - it's caused by expansions of CAG triplet
repeats in the gene for Huntingtin. We reckon that works mainly through
effects on RNA structure. Others put it down to the production of cross-
linkable proteins that crystallise in your brain].
Sent via Deja.com http://www.deja.com/
Before you buy.
In article
<A781CA86DF5A45B6.7291C99C...@lp.airnews.net>,
lor...@nospam.nineball.org (Derek S. Ray) wrote:
> On Thu, 23 Sep 1999 12:42:57 +1000, m.to...@student.canberra.edu.au> (Michael F. Tomkins) wrote:
>
> >> L. Scott Johnson <sjoh...@math.sc.edu> wrote in message
> >> news:37E8F7AB...@math.sc.edu...
> >> > Air, heated by the lightning strike, expands rapidly, causing the
> >> > sound waves that make up thunder (a sonic boom).
> >> >Really!
>
> really.
>
> >It is correct that the lighting arrives with a "crack" sound closly
> >followed by thunder, but they are not connected. The thunder comes from
> >the cloud and the lightning crack from the lightning. I have had the
>
> No, really, what he said IS correct. The delay you hear between the
> lightning and thunder is related to both distance from the strike and
> time it takes the air to expand. Factual Scientific Proof and all.
>
> >awning above me struck and been in a vehicle that has been struck and the
> >second time I had oppertunity to place my fingers in my ears as a reaction
> >to the lightning strike before the thunder arrived. You know how loud the
> >thunder is if it has happened to you. I suppose you could call them
> >lightning reflexes.
>> If a car you were in had been struck, (a) it would have totally ceased
> to operate, and (b) you would have been Crispy Fried Kindred.
Where did I say car? Vehicle, a electric tram to be exact. Blew the
circuits breakers and we had to run on backup to the next stop. And I
reitterate the lightning "cracked" (a seperate sound with a flash) then
was followed by thunder. It is particlarly unplesent to be sitting in a
suddenly darkend tram then the loudest thunder you have heard hits.
The other one I was under a walkway awning when I recived a static shock,
with said crack of lightning (a seperate noise and flash of light),
thunder arrived in time to have my fingers in my ears.
>It may
> just have SOUNDED like you were struck, or perhaps it hit directly
> across a hill in front of you, but when lightning really hits anywhere
> near you, the thunder is near-instantaneous. You certainly wouldn't
> have had time to put your fingers in your ears, much less do anything
> more than flinch.
I have no doubt that it is near-instantanous. The thunder comes from the
discharge in the cloud, which is about 500m (1500ft) directly above you.
The lightning does not produce thunder in it's bolt, it is produced by the
discharge in the cloud.
I grow tired of this, belive what you must.
--
And the crowds (yea and verily) did gaze at him in wonderment,
as to what this holy man had been smoking,
(and what he was going to do with those two pencils up his nose).
Michael F. Tomkins m.to...@student.canberra.edu.au
>
> Volkswagens, on the other hand, might not even notice.
:)
got to love those things. A friend had designed, but not built a Large
TEsla coil to generate a short ranged EMP. He planned to drive his VW
around and zap other cars and police vehicles.
>
> >Raille
> >from SW Michigan, the Lightning State
>> where exactly? i lived in Grand Rapids a long time... and you forgot
> to include the Tornado Corner, the Twelve-Inches-in-Four-Hours state,
The SW corner of Allegan Country, part of Tornado alley.
> the Mistaken-Weatherman assumption... Which was actually a great shock
What the heck is a weather man? :)
Seems they can't get the weather right on friday for Saturday.
> to me when I moved down to Atlanta. I had been used to taking the
> weatherman with a grain of salt and relying on looking out my window
> to see what the weather would be like - it was literally culture shock
> to move here and find people making plans for the weekend on Wednesday
> based on what the weatherman was saying... and having him be right!
>
> -- Derek
Your right, that is shocking. More so that the lightning strike!
Raille
Kevin Mitcham wrote:
> ObJyhad: Can elysium be used to avoid weather control damage? Is there
> an order of resolution for "before range" effects? I know in general
> effects are "as soon as the card is played" but I can easily see that
> becoming an issue if a FOR thaum vampire gets blocked by a prey with
> the elysium. They need to end the combat before the dawn op/weather
> control combo goes off...
* Weather Control's damage will occur even if combat is subsequently
ended before range (by Mariel or Elysium: Arboretum, e.g.)
[LSJ 19971110]
If you tape the Elysium before Weather Control is played, however, then
you'd be safe.
--
LSJ (vte...@wizards.com) V:TES Net.Rep for Wizards of the Coast.
Links to revised rulebook, rulings, errata, and tournament rules:
http://www.wizards.com/VTES/rules.asp
>Umm, we are seeing so many theories put forth here I am hesitant to
>enter the fray, but I think the insulation provided by your tires is
>worthless when you consider the voltages of lightning.
Ooh, ooh. Pseudo-chemistry (really materials science) stuff! I'm not quite
in my element, but...
The insulation value of rubber is ca. 500 Volts per mil (thousandth of an
inch), as compared to air at roughly 75 Volts per mil. You're right, in
that the distances involved as compared to the voltage of the bolt
(estimated in gigavolts, really big) make the insulation value of the
rubber negligible. The only thing the higher insulation value results in is
heat generated on the surface of the tire, as it resists the electricity
flowing through and around it. That's why the tires melt so often when a
car gets hit.
>It just arced
>across hundreds/thousands of feet of air- the 6 inches between your car
>and the ground don't matter much, tires or not.
Exactly. Although electricity will tend to go over the surface of the
rubber tires in its travel to reach ground. It will also arc from the metal
drivetrain to the ground. Rubber will also give the slight delay in
discharge of some residual electricity (whatever the car can store as a
capacitor) Thus the static discharge as you step out of the charged car
(time after the strike determines how strong this would be. You'd have to
be pretty quick to get enough of a jolt to knock you down... either that or
your car would have to be really good at holding a charge, which they
typically aren't)
Cars are safe because
>the electricity flows around the outside of the car (it being a nice
>conducting surface)
So long as you have a conductive exterior (and not polymer) or a metal frame
(like a Saturn; polymer body, steel frame)...
> rather than through it- so if you are inside the
>car, you won't get hurt. Not because the car is safe, but because the
>_inside_ of the car is safe.
>
This is true only as long as the exterior is more conductive than the
interior...
>I have no clue if the cars electircal systems would survive. I tend to
>doubt it, but can't make a useful comment.
>
I'm surprised we don't have an EE who plays Jyhad... This part is black
magic to me, too...
[ quoted text not captured ]
On Fri, 24 Sep 1999 13:46:31 +1000, m.to...@student.canberra.edu.au
(Michael F. Tomkins) wrote:
>circuits breakers and we had to run on backup to the next stop. And I
>reitterate the lightning "cracked" (a seperate sound with a flash) then
>was followed by thunder. It is particlarly unplesent to be sitting in a
>suddenly darkend tram then the loudest thunder you have heard hits.
That "crack" is also thunder. It's just thunder within fifty feet of
you, which despite being the same sound, does sound a lot different
than thunder 1500ft away from you in the clouds. It's still thunder
though, as LSJ said: superheated air expanding rapidly.
>I have no doubt that it is near-instantanous. The thunder comes from the
>discharge in the cloud, which is about 500m (1500ft) directly above you.
>The lightning does not produce thunder in it's bolt, it is produced by the
>discharge in the cloud.
Not quite accurate, see above. But that's OK, since:
>I grow tired of this, belive what you must.
^^^^^^^^^^^^^^^^^^^^^
statements like this are, frankly, usually made by idiots anyway, so I
don't expect coherence.
-- Derek
PEACE, n. In international affairs, a period of cheating
between two periods of fighting.
[ quoted text not captured ]
Derek S. Ray <lor...@nospam.nineball.org> wrote:
: If a car you were in had been struck, (a) it would have totally ceased
: to operate, and (b) you would have been Crispy Fried Kindred. It may: just have SOUNDED like you were struck, or perhaps it hit directly
: across a hill in front of you, but when lightning really hits anywhere
: near you, the thunder is near-instantaneous. You certainly wouldn't
: have had time to put your fingers in your ears, much less do anything
: more than flinch.
Half right. Lots of stuff in the car might have stopped working, but
in actuality you'd be perfectly safe. The electrical charge would pass
around the outside of the car, leaving you unharmed. It has something to
do with the charge being broken down into positive and negative ions, and
all of one sort being outside (positive, I believe), while the others migrate
inside. Short of being in an actual grounded structure, the inside of a car
is one of the best places to be when lightning strikes.
________________________________________________________
Martin Ralya -- Prince of Ann Arbor -- sky...@umich.edu
Visit the compleat VEKN clan newsletter archive on XILE:
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