| Topic: |
Science > Physics |
| User: |
"Warrick FitzGerald" |
| Date: |
17 Mar 2005 10:15:08 AM |
| Object: |
Voice vs. Cell |
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in which
he makes an interesting statement that I was hoping someone could help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
Thanks
Warrick
.
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| User: "Happy Dog" |
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| Title: Re: Voice vs. Cell |
18 Mar 2005 02:17:17 AM |
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"Warrick FitzGerald" <subs.nntp.wfitzgerald@crtman.com>
I'm busy reading an awesome book called E=mc2 by David Bodanis, in which
he makes an interesting statement that I was hoping someone could help me
understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the speed
of sound, so you technically hear the sound from the cell phone before the
sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
He's wrong. He would be correct if he were talking about radios in direct
communication with each other. Sound slow. EMR fast. The signal between
GSM cell phones is delayed by 200+ms. There is a huge amount of processing
that happens between the time the analog signal is recorded by one handset
and played by the other. Take two of them . Call one from the other and
listen to one in each ear.
http://www.mobileshop.org/howitworks/digitising.htm
moo
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| User: "Franz Heymann" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 04:37:12 PM |
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"Warrick FitzGerald" <subs.nntp.wfitzgerald@crtman.com> wrote in
message news:g2i_d.3$5d2.563@news.uswest.net...
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
which
he makes an interesting statement that I was hoping someone could
help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell
phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
EM waves move at a speed of 300,000,000 metres per second in air
Sound waves move at only about 330 metres per second in air, nealy
1,000,000 times slower than EM waves.
--
Franz
"One Galileo in 2000 years is enough."
Pope Pius XII
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| User: "the other Jumby" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 11:02:30 AM |
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"Warrick FitzGerald" <subs.nntp.wfitzgerald@crtman.com> wrote in message
news:g2i_d.3$5d2.563@news.uswest.net...
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in which
he makes an interesting statement that I was hoping someone could help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
Thanks
Warrick
That is not really true, now.
There is a processing delay in each cellphone, and in the networks, this
adds up to 0.5 to 1.5 seconds.
Sound is about 1000 ft/sec so the other person would have to be 500 feet
away for the cell to win.
The old phones, POTS, directly connected by wires, is much faster, does not
have the delay, perhaps 50 to 100 ms.
and would be quicker than sound at about 20 feet or more.
So it depends on what type of phones you have.
.
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| User: "Randy Poe" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 12:45:19 PM |
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the other Jumby wrote:
That is not really true, now.
There is a processing delay in each cellphone, and in the networks,
this
adds up to 0.5 to 1.5 seconds.
I ignored the processing delay, as did the original author
to make a point. However, it's not that bad. I've
actually been on the cell phone with somebody who was only
a few meters away, and a delay of that magnitude would
definitely have been noticeable.
At worst, I'd say it was on the order of the sound
propagation delay.
- Randy
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| User: "John C. Polasek" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 02:32:32 PM |
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On Thu, 17 Mar 2005 11:15:08 -0500, Warrick FitzGerald
<subs.nntp.wfitzgerald@crtman.com> wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in which
he makes an interesting statement that I was hoping someone could help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
Thanks
Warrick
The cell phone message is multiplexed: they might have capacity for
1000 calls on one radio frequency, so if the station is 5 miles away,
it will act like 10,000 miles 2-way bacause a price has to be paid to
exploit the RF bandwidth.
So the ratio of delays would be
10ft/1000ft/sec divided by 10K/186K and so the radio delay would be
less by a ratio of 186/1000 or .186. Thus the radio is faster.
Of course I made the numbers up but I believe they are representative.
There may be other delays in the radio link.
Mr. Dual Space
If you have something to say, write an equation.
If you have nothing to say, write an essay
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| User: "Lady Chatterly" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 03:05:22 PM |
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In article <sopj31llcprkj4p5bi6ba0kn8u377jfeen@4ax.com>
John C. Polasek <jpolasek@cfl.rr.com> wrote:
On Thu, 17 Mar 2005 11:15:08 -0500, Warrick FitzGerald
<subs.nntp.wfitzgerald@crtman.com> wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in which
he makes an interesting statement that I was hoping someone could help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
Thanks
Warrick
The cell phone message is multiplexed: they might have capacity for
1000 calls on one radio frequency, so if the station is 5 miles away,
it will act like 10,000 miles 2-way bacause a price has to be paid to
exploit the RF bandwidth.
So the ratio of delays would be
10ft/1000ft/sec divided by 10K/186K and so the radio delay would be
less by a ratio of 186/1000 or .186. Thus the radio is faster.
Of course I made the numbers up but I believe they are representative.
There may be other delays in the radio link.
You are not Very smart.
Mr. Dual Space
Perhaps you Will be waiting for your purposes too, but I did not
research anything either.
If you have something to say, write an equation.
If you have nothing to say, write an essay
Where did you get a lot of randomness in the world?
--
Lady Chatterly
"Damn - he lits the bot but not me! See what respecting the moratorium
on poaking Joey Baby has gotten me?" -- Roofshadow
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| User: "Uncle Al" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 02:47:19 PM |
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Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in which
he makes an interesting statement that I was hoping someone could help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
Sure. So?
How is this possible? He kind of explains it in the book, but I dont
really get it.
Path one: Mouth to ear 20 feet away. Sound travels at around 1100
ft/sec. Elapsed time 18 msec.
Path two: Mouth to phone 2" away, 0.15 msec.
100 feet of conductor inside phone #1 at c/3, .0003 msec
20 feet of propagation across room at c, .0000020 msec
100 feet of conductor inside phone #2 at c/3, .0003 msec
Phone to ear 2" away, 0.15 msec
Path two sums to 0.3 msec
Calling on a phone is faster than shouting by a factor of more than
50. If you sit in the back row of a large concert hall, cymbals or a
drum are whacked perceptably before you hear them. The decoupling is
quite remarkable at the Hollywood Bowl.
--
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: "Happy Dog" |
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| Title: Re: Voice vs. Cell |
18 Mar 2005 02:23:49 AM |
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"Uncle Al" <UncleAl0@hate.spam.net> wrote
20 feet of propagation across room at c, .0000020 msec
Cell phones don't communicate directly with each other. There's also a
bunch of processing that happens to the signal that causes delays in the
triple millisecond range. Echo suppression in the sidetone was a hurdle.
Take two cell phones and test it empirically.
moo
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| User: "John C. Polasek" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 04:43:27 PM |
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On Thu, 17 Mar 2005 12:47:19 -0800, Uncle Al <UncleAl0@hate.spam.net>
wrote:
Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in which
he makes an interesting statement that I was hoping someone could help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
Sure. So?
How is this possible? He kind of explains it in the book, but I dont
really get it.
Path one: Mouth to ear 20 feet away. Sound travels at around 1100
ft/sec. Elapsed time 18 msec.
Path two: Mouth to phone 2" away, 0.15 msec.
100 feet of conductor inside phone #1 at c/3, .0003 msec
Now add 5 miles to the station and 5 back where your conversation is
chopped into packets to be shared and multiplexed with 1000 or more
others and put on a revolving digital conveyor belt to be picked off
and reassembled later.
20 feet of propagation across room at c, .0000020 msec
You're thinking of something like the $19 toy phones that are in
direct radio contact.
100 feet of conductor inside phone #2 at c/3, .0003 msec
Phone to ear 2" away, 0.15 msec
Path two sums to 0.3 msec
Calling on a phone is faster than shouting by a factor of more than
50. If you sit in the back row of a large concert hall, cymbals or a
drum are whacked perceptably before you hear them. The decoupling is
quite remarkable at the Hollywood Bowl.
Mr. Dual Space
If you have something to say, write an equation.
If you have nothing to say, write an essay
.
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| User: "" |
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| Title: Re: Voice vs. Cell |
18 Mar 2005 06:58:41 AM |
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Uncle Al wrote:
Path one: Mouth to ear 20 feet away. Sound travels at around 1100
ft/sec. Elapsed time 18 msec.
Path two: Mouth to phone 2" away, 0.15 msec.
100 feet of conductor inside phone #1 at c/3, .0003 msec
20 feet of propagation across room at c, .0000020 msec
100 feet of conductor inside phone #2 at c/3, .0003 msec
Phone to ear 2" away, 0.15 msec
Path two sums to 0.3 msec
Calling on a phone is faster than shouting by a factor of more than
50. If you sit in the back row of a large concert hall, cymbals or a
drum are whacked perceptably before you hear them. The decoupling is
quite remarkable at the Hollywood Bowl.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
Remember a real Huh? moment...
Standing on a high lookout point on Lake Superior, watching a t'stom
way out from shore. A bright flash of lightning was accompanied, ALMOST
INSTANTLY, by a loud noise.. Static from the AM radio in my car a few
feet away!
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| User: "PD" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 03:00:45 PM |
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Uncle Al wrote:
Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
which
he makes an interesting statement that I was hoping someone could
help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell
phone
before the sound wave from the persons mouth.
Sure. So?
How is this possible? He kind of explains it in the book, but I
dont
really get it.
Path one: Mouth to ear 20 feet away. Sound travels at around 1100
ft/sec. Elapsed time 18 msec.
Path two: Mouth to phone 2" away, 0.15 msec.
100 feet of conductor inside phone #1 at c/3, .0003 msec
20 feet of propagation across room at c, .0000020 msec
I may be wrong, but I thought ALL cell phone calls had to be routed
through nearby towers, even if the two cell phones were sitting next to
each other. Not that it changes much.
100 feet of conductor inside phone #2 at c/3, .0003 msec
Phone to ear 2" away, 0.15 msec
Path two sums to 0.3 msec
Calling on a phone is faster than shouting by a factor of more than
50. If you sit in the back row of a large concert hall, cymbals or a
drum are whacked perceptably before you hear them. The decoupling is
quite remarkable at the Hollywood Bowl.
--
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: "Uncle Al" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 05:38:39 PM |
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PD wrote:
Uncle Al wrote:
Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
which
he makes an interesting statement that I was hoping someone could
help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell
phone
before the sound wave from the persons mouth.
Sure. So?
How is this possible? He kind of explains it in the book, but I
dont
really get it.
Path one: Mouth to ear 20 feet away. Sound travels at around 1100
ft/sec. Elapsed time 18 msec.
Path two: Mouth to phone 2" away, 0.15 msec.
100 feet of conductor inside phone #1 at c/3, .0003 msec
20 feet of propagation across room at c, .0000020 msec
I may be wrong, but I thought ALL cell phone calls had to be routed
through nearby towers, even if the two cell phones were sitting next to
each other. Not that it changes much.
Point taken. The lightspeed delay jogs to the left a couple or three
decimal places. The conclusion remains unaltered. All Uncle Al's
phones are hard-wired. Work for it.
100 feet of conductor inside phone #2 at c/3, .0003 msec
Phone to ear 2" away, 0.15 msec
Path two sums to 0.3 msec
Calling on a phone is faster than shouting by a factor of more than
50. If you sit in the back row of a large concert hall, cymbals or a
drum are whacked perceptably before you hear them. The decoupling is
quite remarkable at the Hollywood Bowl.
--
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: "Mark Martin" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 12:49:07 PM |
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Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
which
he makes an interesting statement that I was hoping someone could
help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
Just change the scenario a little. Instead of the pair talking in the
same room, assume they're talkinh across the country, hundreds of miles
apart. It's really the same thing. They're talking on cell phones. The
cell signals are traveling at the speed of light. The speakers' sound
waves that wash past the phones travel at the speed of sound which, on
Earth, through air, at sea level, is roughly one millionth the speed of
light.
-Mark Martin
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| User: "Randy Poe" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 10:39:20 AM |
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Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
which
he makes an interesting statement that I was hoping someone could
help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
Why shouldn't it be possible? You have two paths from
your mouth to his ear. One is via sound waves through
the air at 330 m/sec. The other is via electromagnetic
waves to the cell tower and back to his phone, at
299,792,458 m/sec. Why shouldn't the second path be
faster? What strikes you as impossible about it?
- Randy
.
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| User: "Warrick FitzGerald" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 11:23:11 AM |
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This is a multi-part message in MIME format.
--------------080306000805050908010703
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Randy Poe wrote:
Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
which
he makes an interesting statement that I was hoping someone could
help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
Why shouldn't it be possible? You have two paths from
your mouth to his ear. One is via sound waves through
the air at 330 m/sec. The other is via electromagnetic
waves to the cell tower and back to his phone, at
299,792,458 m/sec. Why shouldn't the second path be
faster? What strikes you as impossible about it?
- Randy
Thanks Randy,
It's not that I think it's impossible, I was looking for the explanation
you just gave. I know very little about physics and this seemed like a
very interesting point ..
I guess the next big question I'd like to answer is why electromagnetic
waves travel so much faster than sound waves.
To someone like me ( who really does not know much on the topic at all )
... I imagine a sound wave or an electromagnetic as be being one electron
that bumps up against another and causes a sort of ripple effect.
Similar to how I imagine electricity "flows" through a piece of wire ..
but using the electrons in the air around us.
So where my confusion comes in, is how one wave type causes this effect
to happen so much faster than the other.
I realize I'm probably completely wrong here, but hey if I don't voice
my stupidity I guess I'll never be corrected.
Thanks again
Warrick
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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Randy Poe wrote:
<blockquote
cite="mid1111077560.615726.3660@z14g2000cwz.googlegroups.com"
type="cite">
<pre wrap="">Warrick FitzGerald wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
</pre>
</blockquote>
<pre wrap=""><!---->which
</pre>
<blockquote type="cite">
<pre wrap="">he makes an interesting statement that I was hoping someone could
</pre>
</blockquote>
<pre wrap=""><!---->help
</pre>
<blockquote type="cite">
<pre wrap="">me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell phone
</pre>
</blockquote>
<pre wrap=""><!---->
</pre>
<blockquote type="cite">
<pre wrap="">before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I dont
really get it.
</pre>
</blockquote>
<pre wrap=""><!---->
Why shouldn't it be possible? You have two paths from
your mouth to his ear. One is via sound waves through
the air at 330 m/sec. The other is via electromagnetic
waves to the cell tower and back to his phone, at
299,792,458 m/sec. Why shouldn't the second path be
faster? What strikes you as impossible about it?
- Randy
</pre>
</blockquote>
<font size="-1"><font face="Arial">Thanks Randy, <br>
<br>
It's not that I think it's impossible, I was looking for the
explanation you just gave. I know very little about physics and this
seemed like a very interesting point .. <br>
<br>
I guess the next big question I'd like to answer is why electromagnetic
waves travel so much faster than sound waves. <br>
<br>
To someone like me ( who really does not know much on the topic at all
) .. I imagine a sound wave or an </font></font><font size="-1"><font
face="Arial">electromagnetic</font></font> as be being one electron
that bumps up against another and causes a sort of ripple effect.
Similar to how I imagine electricity "flows" through a piece of wire ..
but using the electrons in the air around us. <br>
<br>
So where my confusion comes in, is how one wave type causes this effect
to happen so much faster than the other. <br>
<br>
I realize I'm probably completely wrong here, but hey if I don't voice
my stupidity I guess I'll never be corrected. <br>
<br>
Thanks again<br>
Warrick<br>
<br>
<font size="-1"><font face="Arial"> </font></font><font size="-1"><font
face="Arial"> </font></font>
</body>
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--------------080306000805050908010703--
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| User: "PD" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 11:52:30 AM |
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Warrick FitzGerald wrote:
Randy Poe wrote:
Warrick FitzGerald wrote:
Hi All,
I'm busy reading an awesome book called E=mc2 by David Bodanis, in
which
he makes an interesting statement that I was hoping someone could
help
me understand.
In the book he says:
With 2 people in a room taking to each other via their cell phone.
The speed at which the cell phone signal travels is facter than the
speed of sound, so you technically hear the sound from the cell
phone
before the sound wave from the persons mouth.
How is this possible? He kind of explains it in the book, but I
dont
really get it.
Why shouldn't it be possible? You have two paths from
your mouth to his ear. One is via sound waves through
the air at 330 m/sec. The other is via electromagnetic
waves to the cell tower and back to his phone, at
299,792,458 m/sec. Why shouldn't the second path be
faster? What strikes you as impossible about it?
- Randy
Thanks Randy,
It's not that I think it's impossible, I was looking for the
explanation
you just gave. I know very little about physics and this seemed like
a
very interesting point ..
I guess the next big question I'd like to answer is why
electromagnetic
waves travel so much faster than sound waves.
To someone like me ( who really does not know much on the topic at
all )
.. I imagine a sound wave or an electromagnetic as be being one
electron
that bumps up against another and causes a sort of ripple effect.
For sound, you are essentially correct.
For electromagnetism, however, this is not correct. The fields
themselves "bump" into each other, allowing them to propagate in a
complete vacuum.
This is why you can see but can't hear the sun.
Similar to how I imagine electricity "flows" through a piece of wire
...
but using the electrons in the air around us.
Current in a wire is *much* slower than electromagnetic waves.
So where my confusion comes in, is how one wave type causes this
effect
to happen so much faster than the other.
I realize I'm probably completely wrong here, but hey if I don't
voice
my stupidity I guess I'll never be corrected.
Thanks again
Warrick
.
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| User: "bz" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 12:08:33 PM |
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"PD" <pdraper@yahoo.com> wrote in news:1111081950.697323.302110
@f14g2000cwb.googlegroups.com:
Current in a wire is *much* slower than electromagnetic waves.
The "drift velocity" of individual electrons in a wire is much slower than
electromagnetic waves.
CURRENT in the wire [and the associated ElectroMagneticForce] travel at the
speed of light in the wire which tends to be a bit slower than light in a
vacuum because of the insulation etc which surround the wire, but not *much*
slower.
--
bz
please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.
bz+sp@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
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| User: "PD" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 01:06:16 PM |
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bz wrote:
"PD" <pdraper@yahoo.com> wrote in news:1111081950.697323.302110
@f14g2000cwb.googlegroups.com:
Current in a wire is *much* slower than electromagnetic waves.
The "drift velocity" of individual electrons in a wire is much slower
than
electromagnetic waves.
CURRENT in the wire [and the associated ElectroMagneticForce] travel
at the
speed of light in the wire which tends to be a bit slower than light
in a
vacuum because of the insulation etc which surround the wire, but not
*much*
slower.
I guess that depends on how you define current. If you mean propagation
of signal, then yes, it goes at transmission line speeds, which is some
substantial fraction of c.
If you mean dQ/dt, then this is more tightly coupled with actual charge
transport.
It wasn't quite clear from the OP which sense he meant it, and it's
possible he didn't know there was a distinction. I think of a wire as a
kind of FIFO register. Banging one end produces a bit at the other end
almost instantaneously, but if you are looking for a *particular* bit
to come out...
Thanks for the correction.
PD
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| User: "bz" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 01:48:09 PM |
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"PD" <pdraper@yahoo.com> wrote in news:1111086376.274727.5880
@f14g2000cwb.googlegroups.com:
I think of a wire as a
kind of FIFO register. Banging one end produces a bit at the other end
almost instantaneously, but if you are looking for a *particular* bit
to come out...
Like a pipe full of water, if you force water into one end, [and, in the
case of electrons and a wire, have a complete circuit for electrons] then
water comes out the other 'instantly' where instantly means at the pressure
wave velocity limit of water. If you force dyed water in at one end, it
will take a much longer time for the dye to make its way through the pipe.
'color the electron blue'.... doesn't work but the analogy is pretty valid.
Thanks for the correction.
We are in this life to learn from each other.
'You teach best what you most need to learn' from Illusions by Richard
Bach.
--
bz
please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.
bz+sp@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
.
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| User: "Franz Heymann" |
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| Title: Re: Voice vs. Cell |
17 Mar 2005 04:37:13 PM |
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You have written it HTML.
If you would be good enough to repeat your note in plain text, I will
help you as best I can. However, am not prepared to start a messy
concersation in HTML, since it messes the thread up by making it
impossible to reply in-line
[snip]
--
Franz
"One Galileo in 2000 years is enough."
Pope Pius XII
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