Science > Physics > Speed of sound and light in water and other questions
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Science > Physics |
| User: |
"mikky" |
| Date: |
13 Jan 2005 05:16:00 AM |
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Speed of sound and light in water and other questions |
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
How about the speed of light? Is it possible in any way at all to slow
down the speed of light?
Is it possible to generate sound in space? Are there any particles at
all in space that could help sound to travel? If yes what is the speed
of sound in space?
How does ball lightning work? What kind of electrical charge is this
phenomena and is it possible to recreate in a laboratory?
I read some pages about Mr. Tesla and his experiments. Does anyone
have recommendable links to more about Mr. Tesla?
Thank you in advance for replies.
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| User: "Franz Heymann" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 02:45:44 PM |
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"mikky" <not@now.com> wrote in message
news:qmkcu05lr19t60dlm1ad9c2bo4irhs17pv@4ax.com...
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes
How about the speed of light?
The speed of light in free space always has the same value.
Is it possible in any way at all to slow
down the speed of light?
Only by transmitting it through a medium with a refractive index
greater than one.
Is it possible to generate sound in space?
No. Sound waves travel only in matter.
Are there any particles at
all in space that could help sound to travel?
Yes. Space is not quite empty
If yes what is the speed
of sound in space?
speed = sqrt(gamma * R * T / M)
where
gamma = ratio between specific heat at constant pressure to specific
heat at constant volume.
R = Gas Constant
T = absolute temperature
M = molecular weight
The 1st, 3rd and 4th are values pertaining to the interstellar gas.
[snip]
Franz
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| User: "Brad Guth" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 03:16:47 PM |
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The moon is not silent was an honest topic that I attempted within the
BBC space forum that sucks.
Not sound persay as to the human ear, as it'll require a fairly large
diaphragm (say 1 m2 of thin mylar) and a reflected micro laser beam as
to transfer the energy derived from those impacting atoms that were
originally generated as a weak energy wave or gauntlet of potentially
fast traveling atoms, that'll become detectable and thus easily
converted into what we humans should hear as a result of something
impacting with our moon.
Of course this instrument needs to reside either upon the moon or
perhaps within the ME-L1 nullification zone.
BTW; I believe photons lose 60% of their velocity getting through
diamond. I'm not certain if that applies to the entire spectrum of
photons or just those we can optically observe.
Regards, Brad Guth / GASA-IEIS
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
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| User: "Brad Guth" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 03:46:07 PM |
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Besides the extremely low frequency of cosmic or perhaps gravity waves,
I'm thinking that the speed of other sound in space is actually capable
of remaining extremely fast.
As a dust-bunny strikes the moon at 30+km/s, clearly the displaced and
usually vaporised amount of basalt gets moving along at perhaps as great
as 15 km/s, whereas some of those newly created atoms escape the gravity
of the moon, especially of the impact and solar roasted sodium and
lighter weight atoms are least affected by the lunar gravity.
Increasing that impact to what a fairly substantial kg that's arriving
at 100 km/s and, lo and behold there's got to be absolute loads of
energy waves all about and escaping the moon, along with a fair amount
of displaced basalt that might actually manage to leave orbit (much of
which should land upon Earth). Certainly of any 100 km crater that's 20
km deep is suggesting a rather substantial amount of displacement, and
absolute loads of detectable energy waves having been comprised mostly
of the vaporised basalt. Although, these days at most a few kg per
meteor is what's transpiring unless we're intentionally terraforming the
moon by way of tossing massive blocks of dry-ice and frozen Radon into
the lunar surface for the task of creating an artificial atmosphere.
Regards, Brad Guth / GASA-IEIS
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
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| User: "tadchem" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 11:53:00 AM |
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mikky wrote:
<snip>
Is it possible to generate sound in space? Are there any particles at
all in space that could help sound to travel? If yes what is the
speed
of sound in space?
The speed of sound depends on the temperature, mole weight, and heat
capacity ratio of a fluid:
http://scienceworld.wolfram.com/physics/SpeedofSound.html
If the average distance that a molecule has to travel before it
encounters another molecule is not much smaller than the wavelength of
the sound, then sound has difficulty propagating.
Shock waves are a form of sound - since there is only one pressure
pulse, there is no 'frequency' to speak of, and the effective
wavelength is nearly infinite. Supernovae produce shock waves:
http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/09/
How does ball lightning work? What kind of electrical charge is this
phenomena and is it possible to recreate in a laboratory?
The non-linearity of the electrostatic properties of air allow a hot,
electrically conducting plasma to be confined by an insulating layer of
air in a non-dissipative structure - much like a soliton. The plasma
is hot enough to incandesce. The lightning ball gradually cools until
the plasma collapses adiabatically and is snuffed out:
http://www.tbns.net/mediapoet/tech19b.htm
Google "ball lightning"
Tom Davidson
Richmond, VA
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| User: "Uncle Al" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 09:28:58 AM |
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mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Shift your lazy leaden ***** and look it up - as the data per se or as
the equation that describes the phenomenon.
How about the speed of light? Is it possible in any way at all to slow
down the speed of light?
Refractive index. Bose-Einstein codensates and anomalous refraction.
Shift your lazy leaden ***** as get educated. Google, library, "My
Weekly Reader."
Is it possible to generate sound in space?
Yeah. Plasma physics. Do you have a really good sub-woofer?
[snip]
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
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| User: "Rene Tschaggelar" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 05:55:28 AM |
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mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes, there is. In air, it is about 300m/s and in water 1500m/s
if I remember correctly.
How about the speed of light? Is it possible in any way at all to slow
down the speed of light?
The speed of light is 3 *10^8m /s in air and 30% slower in water.
Is it possible to generate sound in space? Are there any particles at
all in space that could help sound to travel? If yes what is the speed
of sound in space?
No, there is no sound in space. As there are no material
carriyng the sound.
Rene
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| User: "Franz Heymann" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 02:45:45 PM |
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"Rene Tschaggelar" <none@none.net> wrote in message
news:41e661b0$0$3412$5402220f@news.sunrise.ch...
mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes, there is. In air, it is about 300m/s and in water 1500m/s
if I remember correctly.
How about the speed of light? Is it possible in any way at all to
slow
down the speed of light?
The speed of light is 3 *10^8m /s in air and 30% slower in water.
Is it possible to generate sound in space? Are there any particles
at
all in space that could help sound to travel? If yes what is the
speed
of sound in space?
No, there is no sound in space. As there are no material
carriyng the sound.
Space is not entirely empty. There is enough gas around to carry
sound waves with frequencies measured in, say, cycles per millenium.
Franz
Rene
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 05:50:11 AM |
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mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes.
<http://en.wikipedia.org/wiki/Speed_of_sound>
How about the speed of light?
Dito.
<http://en.wikipedia.org/wiki/Speed_of_light>
Is it possible in any way at all to slow
down the speed of light?
Not in vacuum, but in materials, definitely.
Is it possible to generate sound in space?
Sound waves can't travel in a (near) vacuum.
Are there any particles at
all in space that could help sound to travel?
There are some particles - but they are so wide apart
that oscillations of one won't disturb the others
in any noticeable way.
If yes what is the speed of sound in space?
How does ball lightning work? What kind of electrical charge is this
phenomena and is it possible to recreate in a laboratory?
<http://en.wikipedia.org/wiki/Ball_lightning>
I read some pages about Mr. Tesla and his experiments.
Mr. Tesla did some important things for science in his
early years, but became quite nutty later.
Does anyone
have recommendable links to more about Mr. Tesla?
<http://en.wikipedia.org/wiki/Nikola_Tesla>
Thank you in advance for replies.
Hint: all of your questions could have easily been answered
by going to a good lexicon like Wikipedia, or even by a
Google search.
Bye,
Bjoern
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| User: "pete" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 07:19:43 AM |
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Bjoern Feuerbacher wrote:
mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes.
<http://en.wikipedia.org/wiki/Speed_of_sound>
How about the speed of light?
Dito.
<http://en.wikipedia.org/wiki/Speed_of_light>
Is it possible in any way at all to slow
down the speed of light?
Not in vacuum, but in materials, definitely.
Is it possible to generate sound in space?
Sound waves can't travel in a (near) vacuum.
http://www.popartuk.com/film/alien/in-space-no-one-can-hear-you-scream-st2792-poster.asp
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| User: "Randy Poe" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 05:59:30 AM |
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mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes. Sound generally travels much faster in liquids and
solids than in air. Sound travels about 330 m/sec in air,
and about 1500 m/sec in water.
How about the speed of light?
c = 299792458 m/sec in vacuum.
Speed of light in air is about c/1.003.
Speed of light in water is about c/1.33.
Is it possible in any way at all to slow
down the speed of light?
At the atomic level, no. But there is a bulk effect that
causes light to progress slower through materials than
in vacuum. We call the ratio of c to this "speed of light
in the material" the index of refraction of the material,
traditionally with the symbol n.
Is it possible to generate sound in space?
Sound is a pressure wave. You need a gas in order to have
a pressure.
Are there any particles at
all in space that could help sound to travel?
About one per cubic meter. Not enough that ordinary sound
waves could be defined in any meaningful way.
However, you can talk about the gas spread over millions
of light years, and density variations lasting many years.
That's "sound", and it's what scientists were talking
about when they announced they'd seen the "sound" of
some astronomical event, a stellar explosion I think.
They'd detected periodic pressure variations in a
gas envelope, with a period of (as I recall) thousands
of years.
If yes what is the speed of sound in space?
For a phenomenon like that (pressure variations in
a big gas cloud) it would be the at most the speed of
the particles in the cloud. I don't know what that is.
For audible sound, there is no speed. When a particle
only comes around to your vicinity every second or so,
you can't talk about making pressure variations at a
frequency of 100 Hz. There's nothing to vary.
- Randy
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| User: "G=EMC^2 Glazier" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 09:12:40 AM |
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Hi Poe Sound waves change speed going through different mediums,but not
photons. The photons have one set constant speed. They can appear to
slow down,but in reality just take a longer path(reflected,absorbed,and
emitted) We use this thinking for the reason light from the sun's core
to take 100,000 years to reach the sun's surface. A lab in Cambridge
Ma.slowed photons down to less than 3mph going through cold sodium(close
to absolute zero) This begs the question after going through "What
accelerated it back to "c"? Bert
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| User: "Randy Poe" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 09:53:16 AM |
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G=EMC^2 Glazier wrote:
Hi Poe Sound waves change speed going through different mediums,but
not
photons. The photons have one set constant speed. They can appear to
slow down,but in reality just take a longer
path(reflected,absorbed,and
emitted)
I said that. Perhaps I wasn't clear enough:
"At the atomic level, no. But there is a bulk effect that
causes light to progress slower through materials than
in vacuum."
We use this thinking for the reason light from the sun's core
to take 100,000 years to reach the sun's surface.
I hadn't heard this number.
- Randy
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| User: "PD" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 10:21:11 AM |
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G=EMC^2 Glazier wrote:
Hi Poe Sound waves change speed going through different mediums,but
not
photons. The photons have one set constant speed. They can appear to
slow down,but in reality just take a longer
path(reflected,absorbed,and
emitted) We use this thinking for the reason light from the sun's
core
to take 100,000 years to reach the sun's surface. A lab in Cambridge
Ma.slowed photons down to less than 3mph going through cold
sodium(close
to absolute zero) This begs the question after going through "What
accelerated it back to "c"? Bert
OK, I'm rapidly stepping into an area where I don't know what I'm
talking about, but recall that sound is quantized as well -- phonons in
solids. Is it also true that differences in sound speeds in different
solids are accounted for by absorption/emission arguments? If so, then
what is the speed of a phonon with the medium effects deconvoluted?
PD
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| User: "" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 02:55:52 PM |
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In article <1105617570.233049.185060@f14g2000cwb.googlegroups.com>, "Randy Poe" <poespam-trap@yahoo.com> writes:
mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes. Sound generally travels much faster in liquids and
solids than in air. Sound travels about 330 m/sec in air,
and about 1500 m/sec in water.
How about the speed of light?
c = 299792458 m/sec in vacuum.
Speed of light in air is about c/1.003.
Speed of light in water is about c/1.33.
You're using an inferior light:-) For th light I'm using, the speed
is marginally higher in water than in vacuum.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
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| User: "Creighton Hogg" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 03:01:35 PM |
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On Thu, 13 Jan 2005 wrote:
In article <1105617570.233049.185060@f14g2000cwb.googlegroups.com>, "Randy Poe" <poespam-trap@yahoo.com> writes:
mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes. Sound generally travels much faster in liquids and
solids than in air. Sound travels about 330 m/sec in air,
and about 1500 m/sec in water.
How about the speed of light?
c = 299792458 m/sec in vacuum.
Speed of light in air is about c/1.003.
Speed of light in water is about c/1.33.
You're using an inferior light:-) For th light I'm using, the speed
is marginally higher in water than in vacuum.
Huh? I think this one went over my head.
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| User: "" |
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| Title: Re: Speed of sound and light in water and other questions |
13 Jan 2005 04:05:26 PM |
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In article <Pine.LNX.4.44.0501131501090.8650-100000@erodium.hep.wisc.edu>, Creighton Hogg <wchogg@hep.wisc.edu> writes:
On Thu, 13 Jan 2005 wrote:
In article <1105617570.233049.185060@f14g2000cwb.googlegroups.com>, "Randy Poe" <poespam-trap@yahoo.com> writes:
mikky wrote:
I humbly ask answers to a few things i'm thinking about.
Is there a difference in speed of sound in water and air?
Yes. Sound generally travels much faster in liquids and
solids than in air. Sound travels about 330 m/sec in air,
and about 1500 m/sec in water.
How about the speed of light?
c = 299792458 m/sec in vacuum.
Speed of light in air is about c/1.003.
Speed of light in water is about c/1.33.
You're using an inferior light:-) For th light I'm using, the speed
is marginally higher in water than in vacuum.
Huh? I think this one went over my head.
Oh, one of pet peeves, the post I was responding to includes a
standard combination of two conceptual errors. Let me elaborate.
Note the statement "Speed of light in water is about c/1.33." Now,
where does the 1.33 come from. The OP will probably say "that's the
index of refraction of water". Well, *false*. An index of refraction
is a *function* (of frequency), not a constant. You'll get completely
different ranges of values for RF, IR, visible, x-rays etc. The 1.33
is a close approximation for the index of refraction of water in the
visible range (I'm saying "approximation" since strictly speaking it
changes even within this range, but very little). But the question
was about "speed of light", not just visible light. Now, usually
whaen I'm getting to this point, somebody pipes in and says, "yes,
sure, but usually when we talk about the speed of light with no
qualifiers we mean 'vicible light'". Nope, in physics we most
certainly ***do not*** mean this. We mean "all EM radiation".
OK, so back to the point, the indices of refraction for all matter in
the x-ray range and above (that's the "light I'm using") are slightly
below 1. So, the *phase velocity* of light in this frequency range,
in matter, is slightly higher than in vacuum.
That's the point where the xlaim can be made "but who said we're
taling about phase velocity?" Well, if you use c/n, you're talking
phase velocity. If you intend to use one of the other measures (group
velocity, information propagation velocity, energy transport velocity)
then you can no longer automatically use c/n. And that's the second
conceptual error I'm talking about, the automatic assumption that when
we talk about speed of light we mean phase velocity.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
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