| Topic: |
Science > Physics |
| User: |
"Bob" |
| Date: |
26 Sep 2004 02:13:14 PM |
| Object: |
accidental invention of light as a wave |
While studying about light I came to know that the invention of
electromagnetic wave nature of light is accidental.(serendipity?)
Can anyone throw more LIGHT on that accident?
(and also to assure you that this is not a part of my homework.I am
asking you out of sheer curiosity)
greetings,
bob
.
|
|
| User: "tadchem" |
|
| Title: Re: accidental invention of light as a wave |
26 Sep 2004 04:05:09 PM |
|
|
"Bob" <bob_peterson@rediffmail.com> wrote in message
news:e80b0472.0409261113.4bafeb12@posting.google.com...
While studying about light I came to know that the invention of
electromagnetic wave nature of light is accidental.(serendipity?)
Can anyone throw more LIGHT on that accident?
(and also to assure you that this is not a part of my homework.I am
asking you out of sheer curiosity)
I don't know if it can properly be called an "invention" - a better word
would be "discovery."
Thomas Young deserves a lot of credit for this:
http://en.wikipedia.org/wiki/Thomas_Young_%28scientist%29
as does Fresnel:
http://en.wikipedia.org/wiki/Augustin-Jean_Fresnel
from their observation of diffraction in interference patterns produced by
light and the similarity of this diffraction to that produced by waves. A
"pure" particle does not diffract.
Sir Isaac Newton championed the concept of light as particles:
http://en.wikipedia.org/wiki/Sir_Isaac_Newton
Even though one of his early observations, Newton's Rings:
http://scienceworld.wolfram.com/physics/NewtonsRings.html
actually supports the *wave* nature of light, and the physical explanation
requires use of the light's *wavelength*.
Basically, there were serious disagreements between Newton and Fresnel over
whether light was a particle or a wave. Incontrovertible proof of the
particle nature of light had to wait for studies of the photoelectric effect
and Einstein's explanation of it:
http://scienceworld.wolfram.com/physics/PhotoelectricEffect.html
There is general agreement among physicists that, whatever a 'photon' really
is, whether is it seen as a particle or a wave depends on *how* the
observations are made. Mathematical physicists recognize that a four-tensor
is the minimum mathematical quantity that can exhibit both wave and particle
behavior, independently depending upon the nature of the transforms applied
to the tensor. (I stress "minimum" because higher order tensors can do the
same, and may be able to do other things we haven't observed yet.) These
four-tensors are also Lorentz-invariant, and thus satisfy the requirements
of Special Relativity.
Tom Davidson
Richmond, VA
.
|
|
|
| User: "Stéphane Coël" |
|
| Title: Re: accidental invention of light as a wave |
27 Sep 2004 10:28:26 AM |
|
|
Mathematical physicists recognize that a four-tensor
is the minimum mathematical quantity that can exhibit both wave and
particle
behavior, independently depending upon the nature of the transforms applied
to the tensor.
Can you give me some understandable details on how this quantity can
exhibit the behavior of a particle or a wave.
Does this mean that behavior of particle and waves can be represented
by tensors?
I ask "understandable" because I am not a mathematician, I know only matrix
and vector as an engineer.
Thanks for your help.
--
Stéphane Coël
"tadchem" <tadchemNOSPAM@comcast.net> a écrit dans le message de news:
yPSdnTx15-70rcrcRVn-ig@comcast.com...
"Bob" <bob_peterson@rediffmail.com> wrote in message
news:e80b0472.0409261113.4bafeb12@posting.google.com...
While studying about light I came to know that the invention of
electromagnetic wave nature of light is accidental.(serendipity?)
Can anyone throw more LIGHT on that accident?
(and also to assure you that this is not a part of my homework.I am
asking you out of sheer curiosity)
I don't know if it can properly be called an "invention" - a better word
would be "discovery."
Thomas Young deserves a lot of credit for this:
http://en.wikipedia.org/wiki/Thomas_Young_%28scientist%29
as does Fresnel:
http://en.wikipedia.org/wiki/Augustin-Jean_Fresnel
from their observation of diffraction in interference patterns produced by
light and the similarity of this diffraction to that produced by waves. A
"pure" particle does not diffract.
Sir Isaac Newton championed the concept of light as particles:
http://en.wikipedia.org/wiki/Sir_Isaac_Newton
Even though one of his early observations, Newton's Rings:
http://scienceworld.wolfram.com/physics/NewtonsRings.html
actually supports the *wave* nature of light, and the physical explanation
requires use of the light's *wavelength*.
Basically, there were serious disagreements between Newton and Fresnel
over
whether light was a particle or a wave. Incontrovertible proof of the
particle nature of light had to wait for studies of the photoelectric
effect
and Einstein's explanation of it:
http://scienceworld.wolfram.com/physics/PhotoelectricEffect.html
There is general agreement among physicists that, whatever a 'photon'
really
is, whether is it seen as a particle or a wave depends on *how* the
observations are made. Mathematical physicists recognize that a
four-tensor
is the minimum mathematical quantity that can exhibit both wave and
particle
behavior, independently depending upon the nature of the transforms
applied
to the tensor. (I stress "minimum" because higher order tensors can do the
same, and may be able to do other things we haven't observed yet.) These
four-tensors are also Lorentz-invariant, and thus satisfy the requirements
of Special Relativity.
Tom Davidson
Richmond, VA
.
|
|
|
| User: "tadchem" |
|
| Title: Re: accidental invention of light as a wave |
28 Sep 2004 08:06:39 AM |
|
|
"Stéphane Coël" <stephane.coel@skynet.be> wrote in message news:<41583197$0$9000$ba620e4c@news.skynet.be>...
<snip>
Can you give me some understandable details on how this quantity can
exhibit the behavior of a particle or a wave.
Does this mean that behavior of particle and waves can be represented
by tensors?
I ask "understandable" because I am not a mathematician, I know only matrix
and vector as an engineer.
Thanks for your help.
--
Stéphane Coël
A scalar field associates a single value with every point in space
and, if applicable, time. Examples of scalar fields would be
gravitational potential energy, density, pressure - any variable that
can be represented by a single numerical value but can change with
location or time.
http://mathworld.wolfram.com/ScalarField.html
A vector field associates a set of N values with every point in
N-dimensional space and, if applicable, time. Examples of vector
fields are streamlines of fluid flow, classical magnetic fields - any
variable that can be represented by a vector but can change with
location or time.
http://mathworld.wolfram.com/Vector.html
http://mathworld.wolfram.com/VectorField.html
Sometimes a vector alone is not enough, and one must *define* the
direction of the vector by convention. This is the case with stress,
for example. The "vector" representation is actually a special case
of a tensor field.
http://mathworld.wolfram.com/Tensor.html
A tensor field in N-dimensional space associates a set of N^2 values
with every point in space and, if applicable, time. There are many
pieces of information that can be extracted from this tensor,
including the determinant (a scalar field), the divergence (a true
vector field), and the curl (a pseudo-vector field).
In electromagnetism, for example, these values represent the (scalar)
charge density, the (vector) electric field, and the (pseudovector)
magnetic field. In addition, transformation operators equivalent to
translation and rotation of coordinate can be applied to "see" how
these tensors "look" from a different perspective. Certain values
(such as charge or total energy) will remain unaffected by these
transformations - they remain "invariant" (a word that comes up a lot
in discussions of Special Relativity).
If one sets up the Schroedinger Wave Equation for a particle moving at
the speed of light with no localized potential (with appropriate
boundary conditions) and solves it in 4-dimensional space-time, the
general solution is a 4-tensor that has components of a plane wave and
a Gaussian probability density.
One then needs to apply different transformations to the tensor to
extract the data of interest such as the energy/wavelength, the
location, the direction, the total angular momentum, the polarization,
and so on. Applying any of these transformations will give you the
desired piece of data, but will simultaneously *prevent* you from
accessing other data.
Some of these transformations will reduce the tensor (a 16-valued
function) to a travelling wave (a 4-valued function) and others will
reduce it to a particle (a single-valued function).
Hope this helps...
Tom Davidson
Richmond, VA
.
|
|
|
| User: "Stéphane Coël" |
|
| Title: Re: accidental invention of light as a wave |
28 Sep 2004 02:26:15 PM |
|
|
Thanks for your reply.
Yes it helps me.
It's nice to know how the concepts of particle and wave of the language
are formalized by the mathematical language.
--
Stéphane Coël
"tadchem" <thomas.davidson@dla.mil> a écrit dans le message de news:
130fe1c3.0409280506.6e37fa5a@posting.google.com...
"Stéphane Coël" <stephane.coel@skynet.be> wrote in message
news:<41583197$0$9000$ba620e4c@news.skynet.be>...
<snip>
Can you give me some understandable details on how this quantity can
exhibit the behavior of a particle or a wave.
Does this mean that behavior of particle and waves can be represented
by tensors?
I ask "understandable" because I am not a mathematician, I know only
matrix
and vector as an engineer.
Thanks for your help.
--
Stéphane Coël
A scalar field associates a single value with every point in space
and, if applicable, time. Examples of scalar fields would be
gravitational potential energy, density, pressure - any variable that
can be represented by a single numerical value but can change with
location or time.
http://mathworld.wolfram.com/ScalarField.html
A vector field associates a set of N values with every point in
N-dimensional space and, if applicable, time. Examples of vector
fields are streamlines of fluid flow, classical magnetic fields - any
variable that can be represented by a vector but can change with
location or time.
http://mathworld.wolfram.com/Vector.html
http://mathworld.wolfram.com/VectorField.html
Sometimes a vector alone is not enough, and one must *define* the
direction of the vector by convention. This is the case with stress,
for example. The "vector" representation is actually a special case
of a tensor field.
http://mathworld.wolfram.com/Tensor.html
A tensor field in N-dimensional space associates a set of N^2 values
with every point in space and, if applicable, time. There are many
pieces of information that can be extracted from this tensor,
including the determinant (a scalar field), the divergence (a true
vector field), and the curl (a pseudo-vector field).
In electromagnetism, for example, these values represent the (scalar)
charge density, the (vector) electric field, and the (pseudovector)
magnetic field. In addition, transformation operators equivalent to
translation and rotation of coordinate can be applied to "see" how
these tensors "look" from a different perspective. Certain values
(such as charge or total energy) will remain unaffected by these
transformations - they remain "invariant" (a word that comes up a lot
in discussions of Special Relativity).
If one sets up the Schroedinger Wave Equation for a particle moving at
the speed of light with no localized potential (with appropriate
boundary conditions) and solves it in 4-dimensional space-time, the
general solution is a 4-tensor that has components of a plane wave and
a Gaussian probability density.
One then needs to apply different transformations to the tensor to
extract the data of interest such as the energy/wavelength, the
location, the direction, the total angular momentum, the polarization,
and so on. Applying any of these transformations will give you the
desired piece of data, but will simultaneously *prevent* you from
accessing other data.
Some of these transformations will reduce the tensor (a 16-valued
function) to a travelling wave (a 4-valued function) and others will
reduce it to a particle (a single-valued function).
Hope this helps...
Tom Davidson
Richmond, VA
.
|
|
|
|
|
|
|
| User: "Morituri-Max" |
|
| Title: Re: accidental invention of light as a wave |
26 Sep 2004 02:15:50 PM |
|
|
Bob wrote:
While studying about light I came to know that the invention of
electromagnetic wave nature of light is accidental.(serendipity?)
Can anyone throw more LIGHT on that accident?
(and also to assure you that this is not a part of my homework.I am
asking you out of sheer curiosity)
not meant in a bad way, I just always find it hilarious when a complete stranger
says "no really take my word for it its not homework/etc".. the funny thing
about it is that if someone who doesn't *know* you assumes you are cheating, why
do you think they will believe a strangers claim that they *aren't*?
Grin.. have a good one, hope someone else can point you at it..
.
|
|
|
|
| User: "N:dlzc D:aol T:com \dlzc\ N: dlzc1 D:cox" |
|
| Title: Re: accidental invention of light as a wave |
26 Sep 2004 04:00:25 PM |
|
|
Dear Bob:
"Bob" <bob_peterson@rediffmail.com> wrote in message
news:e80b0472.0409261113.4bafeb12@posting.google.com...
While studying about light I came to know that the invention of
electromagnetic wave nature of light is accidental.(serendipity?)
Can anyone throw more LIGHT on that accident?
(and also to assure you that this is not a part of my homework.I am
asking you out of sheer curiosity)
Google Advanced
Exact phrase "wave nature of light"
5,610 hits, with some reasonable ones on the first ten hits.
.... ancient history, starting perhaps in the 1600s.
David A. Smith
.
|
|
|
|
| User: "Amr Morsi" |
|
| Title: re:accidental invention of light as a wave |
26 Sep 2004 04:36:00 PM |
|
|
Hi Bob,
At the beginning, although electricity and magnetism were known (but
not defined to be of same nature), it wasn't until Maxwell's age when
he noticed that the velocity of electromagnetic waves have the same
velocity as light (after proving that electricity and magnetism have
the same nature and coming up with the 4 Maxwell's Equations). From
this fact, Maxwell deduced that light is un electromagnetic wave.
After that, it became more obvious that this fact is true as it was
found that light obeys all electromagnetic phenomena (such as
refraction) and as it became clear that the source of light is the
transition of electrons from one level to another in the atomic
level.
Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
----------------------------------------------------------
http://www.usenet.com
.
|
|
|
| User: "EjP" |
|
| Title: Re: accidental invention of light as a wave |
27 Sep 2004 08:36:29 AM |
|
|
Small but important correction...
Amr Morsi wrote:
Hi Bob,
At the beginning, although electricity and magnetism were known (but
not defined to be of same nature), it wasn't until Maxwell's age when
he noticed that the velocity of electromagnetic waves have the same
/\
predicted
velocity as light (after proving that electricity and magnetism have
the same nature and coming up with the 4 Maxwell's Equations). From
this fact, Maxwell deduced that light is un electromagnetic wave.
Non visible EM waves were not observed, let alone their
velocity measured, until after Maxwell's death.
-E
After that, it became more obvious that this fact is true as it was
found that light obeys all electromagnetic phenomena (such as
refraction) and as it became clear that the source of light is the
transition of electrons from one level to another in the atomic
level.
Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
----------------------------------------------------------
http://www.usenet.com
.
|
|
|
| User: "Harry Conover" |
|
| Title: Re: accidental invention of light as a wave |
27 Sep 2004 05:20:47 PM |
|
|
EjP <nospam@hackers.are.bad> wrote in message news:<cj94pn$c5g$1@info4.fnal.gov>...
Small but important correction...
Amr Morsi wrote:
Hi Bob,
At the beginning, although electricity and magnetism were known (but
not defined to be of same nature), it wasn't until Maxwell's age when
he noticed that the velocity of electromagnetic waves have the same
/\
predicted
velocity as light (after proving that electricity and magnetism have
the same nature and coming up with the 4 Maxwell's Equations). From
this fact, Maxwell deduced that light is un electromagnetic wave.
Non visible EM waves were not observed, let alone their
velocity measured, until after Maxwell's death.
Indeed true.
The wave nature of light was clearly demonstrated by both Thomas Young
(and) Pohl circa 1800, demonstrating both the wave nature of light as
well as providing providing a means to measure its wavelength and
velocity through the use of double-slit interference. (Young's
Interomenter). Pohl accomplisished an equivalent result using the
interference pattern produced by the light from a point source light
passing though a thin sheet of mica. Fresnel and others advanced this
concept by 1827.
At this time both the wavelength and velocity of visible light has
been well extablished, and it's velocity was already known to be
approximately 3x10^8 meters/second.
The next great step was the work of Maxwell, when in 1873 he showed
mathematically that an oscillating electrical circuit should radate
ELECTROMAGNETIC WAVES. The predicted propagation velocity of the waves
could be computer. It remained for Hertz to experimentally confirm
Maxwell's theories.
It was 15 years after Maxwell's conclusion that Hertz suceeded in
producing short wavelength waves of undoubedly electromagnetic in
origin, and demonstrated that they could be refracted, reflected,
focused, polarized, just as could waves of light. Hertz was also able
to measure their propatation velocity, which closly matched the
already know velocity of light waves, hence the conclusion that "if
quacks like a duck, and walks at the same velocity as a duck", light
is of the same stuff as electromagnetic radiation.
Sadly, Maxwell died in 1879, so unfortunately he didn't live to see
Hertz's work confirm his brilliant theoretical deductions, and there
you are entirely correct.
Harry C.
.
|
|
|
|
|
|
| User: "Gregory L. Hansen" |
|
| Title: Re: accidental invention of light as a wave |
26 Sep 2004 08:54:24 PM |
|
|
In article <e80b0472.0409261113.4bafeb12@posting.google.com>,
Bob <bob_peterson@rediffmail.com> wrote:
While studying about light I came to know that the invention of
electromagnetic wave nature of light is accidental.(serendipity?)
Can anyone throw more LIGHT on that accident?
(and also to assure you that this is not a part of my homework.I am
asking you out of sheer curiosity)
Serendipitous invention?
There was a great debate in the early 19th(?) century about whether light
was a wave or a particle. And, as I recall the story, Poisson, who
insisted that it was a particle, declared that if it were a wave, there
would be a bright spot in the middle of the shadow cast by a circular
object. The experiment was done, and Poisson's spot was found, and it's
been part of freshman physics labs ever since.
It was a deduction ("If light is a wave, it must have this property, and
if it doesn't have this property it's not a wave") followed by an
experiment. I wouldn't say it really qualifies as serendipity.
Unexpected to some, yes. But it was not discovered on accident.
--
"'No user-serviceable parts inside.' I'll be the judge of that!"
.
|
|
|
| User: "Harry Conover" |
|
| Title: Re: accidental invention of light as a wave |
27 Sep 2004 05:44:20 PM |
|
|
(Gregory L. Hansen) wrote in message news:<cj7rsg$nma$5@hood.uits.indiana.edu>...
In article <e80b0472.0409261113.4bafeb12@posting.google.com>,
Bob <bob_peterson@rediffmail.com> wrote:
While studying about light I came to know that the invention of
electromagnetic wave nature of light is accidental.(serendipity?)
Can anyone throw more LIGHT on that accident?
(and also to assure you that this is not a part of my homework.I am
asking you out of sheer curiosity)
Serendipitous invention?
There was a great debate in the early 19th(?) century about whether light
was a wave or a particle. And, as I recall the story, Poisson, who
insisted that it was a particle, declared that if it were a wave, there
would be a bright spot in the middle of the shadow cast by a circular
object. The experiment was done, and Poisson's spot was found, and it's
been part of freshman physics labs ever since.
Yes, but the demonstration is today usually performed to demonstrated
the concept of diffraction, not Poission's theories.
It was a deduction ("If light is a wave, it must have this property, and
if it doesn't have this property it's not a wave") followed by an
experiment. I wouldn't say it really qualifies as serendipity.
Unexpected to some, yes. But it was not discovered on accident.
Well, it goes without saying that by that time the characteristics of
wave motion (both transverse and longitudional) had been understood
for as long as hundreds of years. The great debate of the early 1800's
involved a disagreement on light being a wave motion or a particle
effect.
Young demonstrated visible light to be a wave motion and 3/4 of a
century later Einstein explained the photo-electric effect by showing
light to be a particle effect and received a Nobel Prize for his work.
So, in spite of the enormous extent of our current knowledge, the
basic arguments and mysteries remains still present.
Current research into this vexing question is producing rather bizarre
observations, such as measurements of the temporal/statistical
distribution of photons on the interference pattern produced by a
simple, two-slit, Young interferometer.
To my simplistic mind, the results remain difficult to comprehend, yet
alone explain anything so far on a truly scientific basis that lead to
newer and more revealing experiments. New age speculation on this
stuff run rampant, but is not yet science. :-)
Harry C.
.
|
|
|
|
|
| User: "Amr Morsi" |
|
| Title: re:accidental invention of light as a wave |
26 Sep 2004 04:36:00 PM |
|
|
It wasn't an accident. It was a deduction from a fact that had come to
light.
Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
----------------------------------------------------------
http://www.usenet.com
.
|
|
|
|
|
Related Articles |
|
|
