| Topic: |
Science > Physics |
| User: |
"aliasjt" |
| Date: |
13 Jan 2005 02:12:53 PM |
| Object: |
sound of thunder |
Dans le livre "oh la physique", assez décrié sur ce groupe, l'auteur
prétend page 172 que le son du tonnerre se propage à une vitesse
bien
plus grande que celle du son, du fait de l'existence d'une onde
d'explosion. On ne retrouve nulle part cette assertion. Quelqu'un
peut-il m'éclairer - c'est le cas de le dire - sur ce sujet ?
Sorry for the language. Now in English :
In the book "oh la physique" (In French, sorry, but there may be an
English edition), it is written that the sound of thunder propagates
at a speed higher than sound speed. It is explained by the fact that
there is at first an explosion wave that is transmitted along an
unknown but non negligible distance, before being transformed into a
normal sound wave. Is there anybody having a hint ?
.
|
|
| User: "Androcles" |
|
| Title: Re: sound of thunder |
13 Jan 2005 03:01:44 PM |
|
|
"aliasjt" <aliasjt@wanadoo.fr> wrote in message
news:1d78da59.0501131212.c95443b@posting.google.com...
Dans le livre "oh la physique", assez décrié sur ce groupe, l'auteur
prétend page 172 que le son du tonnerre se propage à une vitesse
bien
plus grande que celle du son, du fait de l'existence d'une onde
d'explosion. On ne retrouve nulle part cette assertion. Quelqu'un
peut-il m'éclairer - c'est le cas de le dire - sur ce sujet ?
Sorry for the language. Now in English :
In the book "oh la physique" (In French, sorry, but there may be an
English edition), it is written that the sound of thunder propagates
at a speed higher than sound speed. It is explained by the fact that
there is at first an explosion wave that is transmitted along an
unknown but non negligible distance, before being transformed into a
normal sound wave. Is there anybody having a hint ?
I've heard lightning at a 100 ft when the nearby church was struck,
but never measured the speed of sound from it.
Certainly it is a very loud crack up close, the rumble of thunder we are
all familar with is reflections (echos) from the surrounding topology.
The sound speed will indeed be relative to the moving air, but
that movement will not reach far. So in general, the speed of
thunder is no different to the speed of sound.
Androcles
.
|
|
|
| User: "Franz Heymann" |
|
| Title: Re: sound of thunder |
14 Jan 2005 11:45:52 AM |
|
|
"Androcles" <dummy@dummy.net> wrote in message
news:YkBFd.141726$Z7.89758@fe2.news.blueyonder.co.uk...
"aliasjt" <aliasjt@wanadoo.fr> wrote in message
news:1d78da59.0501131212.c95443b@posting.google.com...
Dans le livre "oh la physique", assez décrié sur ce groupe,
l'auteur
prétend page 172 que le son du tonnerre se propage à une vitesse
bien
plus grande que celle du son, du fait de l'existence d'une onde
d'explosion. On ne retrouve nulle part cette assertion. Quelqu'un
peut-il m'éclairer - c'est le cas de le dire - sur ce sujet ?
Sorry for the language. Now in English :
In the book "oh la physique" (In French, sorry, but there may be
an
English edition), it is written that the sound of thunder
propagates
at a speed higher than sound speed. It is explained by the fact
that
there is at first an explosion wave that is transmitted along an
unknown but non negligible distance, before being transformed into
a
normal sound wave. Is there anybody having a hint ?
I've heard lightning at a 100 ft when the nearby church was struck,
but never measured the speed of sound from it.
Certainly it is a very loud crack up close, the rumble of thunder we
are
all familar with is reflections (echos) from the surrounding
topology.
The sound speed will indeed be relative to the moving air, but
that movement will not reach far. So in general, the speed of
thunder is no different to the speed of sound.
The speed of sound in a gas is proportional to the temperature. The
temperature in the vicinity of the stroke is very large.
In addition, the intensity of the pressure wave is very large near the
stroke, so that the ordinary sound theory, in which the sound pressure
is negligible in comparison with the ambient pressure, does not really
apply.
Franz
.
|
|
|
| User: "Bert Hickman" |
|
| Title: Can we hear lightning before the thunder? |
14 Jan 2005 12:16:29 PM |
|
|
A couple of years ago, I was outside when lightning struck a tree
about 100 yards away. I simultaneously "heard" a click as well seeing
the flash. This was followed by the crash of thunder a fraction of a
second later. Was it possible that I somehow sensed the EM pulse which
my brain "translated" into a click?
-- Bert --
--
---------------------------------------------------------------------
We specialize in UNIQUE items! Coins shrunk by huge magnetic fields,
Lichtenberg Figures ("Captured Lightning" in acrylic), & Out-of-Print
technical Books. Stoneridge Engineering - http://www.teslamania.com
---------------------------------------------------------------------
.
|
|
|
|
| User: "tj Frazir" |
|
| Title: Re: sound of thunder |
15 Jan 2005 12:32:10 AM |
|
|
I saw the 12000 pound patty popper hit the ground and go off , Trees
were suppersonic.
The shock wave was vislible and did moc 4.
rice hit the ground allready cooked.
I liked to watch the shock waves threw the leaves of trees when the
marines were expresing conserns with the vc.
The leaves would move from the shock befor I herd the bang.
sound and thermal stress as heat expands the gasses in 1/billion
sec. The shock wave is how fast PSI can travel. A wave of PSI
conducted. sound is emf waiting on mass to move but the shock wave is
psi .
Ive seen leaves get knocked flat over by a shockwave 1 second befor the
sound.
think it was 1975
.
|
|
|
|
|
| User: "" |
|
| Title: Re: sound of thunder |
13 Jan 2005 09:18:29 PM |
|
|
......and the thunder did not propagate from a point source. The
electrical discharge which produces a single thunder clap may travel
thousands of meters, so different distances are involved from the one
very quick event (lightning propagates at c air?)
Jim G
.
|
|
|
|
|
| User: "Uncle Al" |
|
| Title: Re: sound of thunder |
13 Jan 2005 03:31:02 PM |
|
|
aliasjt wrote:
Dans le livre "oh la physique", assez décrié sur ce groupe, l'auteur
prétend page 172 que le son du tonnerre se propage à une vitesse
bien
plus grande que celle du son, du fait de l'existence d'une onde
d'explosion. On ne retrouve nulle part cette assertion. Quelqu'un
peut-il m'éclairer - c'est le cas de le dire - sur ce sujet ?
Sorry for the language. Now in English :
In the book "oh la physique" (In French, sorry, but there may be an
English edition), it is written that the sound of thunder propagates
at a speed higher than sound speed. It is explained by the fact that
there is at first an explosion wave that is transmitted along an
unknown but non negligible distance, before being transformed into a
normal sound wave. Is there anybody having a hint ?
The shockwave at the plasma column is supersonic, as with a detonation
(net displacement of mass over time as the shock propagates). As with
all shockwaves in free space (soliton shockwaves?). it rapidly
degrades into a sonic explosion in which there is no net movement of
conducting medium mass over time. The sonic wave passes through and
the medium is restored to its starting state.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
.
|
|
|
| User: "John Sefton" |
|
| Title: Re: sound of thunder |
14 Jan 2005 02:01:48 AM |
|
|
Uncle Al wrote:
aliasjt wrote:
Dans le livre "oh la physique", assez décrié sur ce groupe, l'auteur
prétend page 172 que le son du tonnerre se propage à une vitesse
bien
plus grande que celle du son, du fait de l'existence d'une onde
d'explosion. On ne retrouve nulle part cette assertion. Quelqu'un
peut-il m'éclairer - c'est le cas de le dire - sur ce sujet ?
Sorry for the language. Now in English :
In the book "oh la physique" (In French, sorry, but there may be an
English edition), it is written that the sound of thunder propagates
at a speed higher than sound speed. It is explained by the fact that
there is at first an explosion wave that is transmitted along an
unknown but non negligible distance, before being transformed into a
normal sound wave. Is there anybody having a hint ?
The shockwave at the plasma column is supersonic, as with a detonation
(net displacement of mass over time as the shock propagates). As with
all shockwaves in free space (soliton shockwaves?). it rapidly
degrades into a sonic explosion in which there is no net movement of
conducting medium mass over time. The sonic wave passes through and
the medium is restored to its starting state.
Actually, Al, I think you're such a flake that
I automatically look for errors due to your biases,
but I have to say this reply did good.
John (backhanded John to you)
.
|
|
|
|
|
|
Related Articles |
|
|
