Chapter 11
The Photoelectric Effect, the Compton Effect
and Blackbody Radiation
"Anyone who conducts an argument by
appealing to authority is not using his intelligence; he is just using his
memory."
Leonardo Da Vinci (1452-1519)
So Far
Up to this point in
the book there have several proofs of the ether drag theory. But this is not the end of the debate. There are still things to understand and
this chapter will deal with three experiments frequently used to prove the
photon theory, or at least prove the particle nature of light (light obviously
does have particle properties).
The Photoelectric
Effect
Einstein did not
discover the photoelectric effect, but he did develop the formulas and
published a paper on the photoelectric effect in 1905. Heinrich Rudolf Hertz (1847 - 1894) had
discovered the photoelectric effect in 1887.
Millikan later proved that Einstein's formulas were correct. Both Einstein and Millikan won Nobel Prizes
for their work on the photoelectric effect.
The photoelectric
effect involved the knocking of electrons off of the surface of metal plates in
a vacuum. The classical model for ether
predicted that the amplitude or intensity of light would
be the determining factor in how many electrons were knocked off of the surface
of the metal plate. For example, with
ocean waves the amplitude of the waves is what provides the bulk of the
energy. The frequency
of ocean waves is fairly irrelevant in providing large amounts of energy. This is logical because the amplitude or
height of several large ocean waves delivers far more water, and thus more
energy, than does a larger number of much smaller waves. Thus, if ether is a wave, then some people
concluded that it should be the amplitude of the waves that provided the bulk
of the energy, not the frequency.
While it is common to
use physical metaphors to prove or disprove a theory, one must be careful when
using physical metaphors when dealing with ether, because light is an
electromagnetic wave or signal, not the cumulative effect of moving, physical
particles. Thus, light is not even
necessarily like sound, because light is an electromagnetic
"bumping," not a physical "bumping."
What the
photoelectric effect proves is that it is the color or frequency
of light that provides the energy of light to knock electrons off of metal
plates (for a particular type of metal), not the amplitude of the
light. For example, for some metals red
light will not change the electron equilibrium of the metal plates, but blue
light will. The amplitude of the light
is of no importance, except that if the frequency of the lightwave is in the
correct range, the amplitude of the light will determine how many electrons are
released.
Using the logic of
the ocean example to prove the photon theory gives the impression that the
photoelectric effect proves that light does not have wave
properties. This is absurd. It is well known that light has wave
properties and particle properties.
Furthermore, if it is the frequency of light that
causes electrons to get knocked off, then it is the wave
properties of light that causes electrons to get knocked off (the term
"frequency" and "wave" mean the same thing). The question is, is it the wave nature of
ether or is it the wave nature of photons that knocks the electrons off?
What is it about this
experiment that can separate the two theories?
Physicists have a difficult time explaining how particles can have wave
properties (e.g. Young's dual-slit experiment, Poisson's spot, etc.), and
suddenly it is the wave properties of photons that are knocking electrons off
of metal surfaces, but the wave properties of ether cannot!
Furthermore, if the
amplitude of ether waves would be expected to knock the electrons off of the
plates, then logically it would be the amplitude of photon waves that would
also knock electrons off of the plates.
Thus, if the ether theory is eliminated, then why shouldn't the photon
theory also be eliminated? There is clearly
a double standard in this debate, as there usually is.
But understanding the
photoelectric effect, relative to ether or photons, was not fully understood
until 1927, when it was discovered that electrons have wave properties. In 1923 or 1924 (depending on what event you
are talking about), Louis De Broglie speculated that matter has wave
properties. But it was not until 1927
that it was accidentally discovered that electrons have wave properties. I quote: "The wave nature of the
electron was experimentally confirmed in 1927 by C.J. Davisson, C.H. Kunsman
and L.H. Germer in the United States and by G.P. Thomson (the son of J.J.
Thomson) in Aberdeen, Scotland. De Broglie's theory of electron matter waves
was later used by Schrödinger, Dirac and others to develop wave
mechanics."
(http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Broglie.html)
Thus we are dealing
with light, which has wave properties, and we are dealing with electrons, which
also have wave properties. Thus, it is
logical that in the unique case of the photoelectric effect the frequency of
the light is more important than is the amplitude of light, whether the ether
or photon theory is correct.
In other words, if
electrons have wave properties, they also have frequency properties. Thus it makes perfect sense that the
frequency of light is what can provide enough energy to release excessive
amounts of electrons from an atom, because electrons have frequency properties
also.
In reality, electrons
are constantly in motion and are constantly being released from a metal plate
(in the experiment two metal plates are placed close to each other and they are
attached via a wire and meter).
Eventually equilibrium will be reached when an equal number of electrons
are moving back and forth through the vacuum and through the wire. Bombarding one plate with a beam of light
with the right frequency (depending on the metal) provides enough energy to
release electrons and destroy the equilibrium.
Maxwell, who was one
of the foremost supporters of ether in the 19th century, stated emphatically
that lightwaves were electromagnetic waves, not physical or material waves,
such as the ocean. Thus, why should the
scientific community relate the properties of a physical wave (e.g. the ocean)
to the properties of an electromagnetic wave (i.e. light), especially when
electrons are involved? That is like
expecting a radio signal and an arrow to have the same properties!
Nevertheless, there
is a physical example of two frequencies joining together to accomplish some
task. This is an example of a signal
through air, sound, having an affect on a physical object. Light is a signal through ether, and it too
can have an affect on a physical object.
It is well known that
the pitch or frequency of sound can break certain types of glass. I quote from an internet site:
"First, the type
of glass matters. As Louis Bloomfield of How Things Work
points out, the glass usually found in windowpanes and cups is relatively soft,
so it vibrates poorly and has no strong natural frequencies. If you tap a glass
of this sort, all you hear is a dull "thunk" sound. There's nothing
with which a high-pitched sound can resonate.
Crystal is better suited because it vibrates well and emits a clear tone
when you tap it. Lead oxide is added to the glass, making the resulting crystal
stronger than ordinary glass. Crystal wine glasses work well for this
experiment because, in addition to being crystal, they are thin and delicate,
and the tubular shape enhances the sound frequency. The real trick to breaking glass with sound is to match the
sound's frequency to that of the glass. You might be able to do this with a
scream, but it's easier for a singer with perfect pitch to create the right
note, especially if that singer's voice is amplified. Each glass will have a
slightly different natural frequency due to minute variations in shape and
composition. When the high-pitched sound and the glass resonate, it causes the
glass to vibrate. If the singer keeps singing the same note at high volume,
eventually the glass will vibrate itself into pieces."
(http://ask.yahoo.com/ask/20011212.html)
Thus, knowing that
ether has frequency properties (as sound does), and knowing the electrons have
frequency properties (as crystal does), we can see from the physical world that
there should be no surprise that the ether theory can easily explain this
phenomenon.
But let us also look
at this phenomenon from a different perspective. If we assume that ether exists, then when an electron drops from
one quantum level to a lower level, we know that this motion can "bump"
or stimulate the ethons surrounding the atom at a specific frequency. In other words, the changing of quantum
levels generates a specific frequency wave of light.
Therefore it stands
to reason that the reverse is also true.
The frequency of light can cause electrons to change quantum
levels. In fact, we know that it is
true because atoms absorb energy from ethons under the right conditions. Since an electron is freed from an atom when
it jumps to a quantum level that doesn't exist for that type of atom, it makes
perfect sense that the frequency of light is what dislodges electrons from
atoms.
(Note: In stating the
above paragraphs, it should be emphasized that it is not known whether the
electron drop "bumps" the ether or whether it is the energy in the
ether that causes the electron to drop down.
In terms of bumping the electron up, it is most certainly the ether that
initiates this event.)
In reality, the
discovery that electrons have wave properties is just one of the many
discoveries that should have reopened the ether-photon debate, but of course it
did not.
The Compton Effect
The Compton effect is
a little more complicated. It involves
the scattering of electrons and the resultant wavelengths associated with the
angles beyond the collision.
I quote from the well-known
book on light by Ditchburn:
"Compton's
original experiments deal with average effects due to large
numbers of collisions. They
cannot, therefore, give direct evidence concerning the change of momentum in
a single collision.
... It is possible to obtain the
change of wavelength from a purely wave-theory [ether] by assuming that the
scattering is a double process in which the light is absorbed and is then
emitted by the moving electron. The
change of wavelength is then ascribed to the Doppler effect." [italics,
underline added][29]
In fact, whether the
photon or ether theory is correct, the electrons jump off of the metal because
of intense localized energy (e.g. heat).
What generates this intense energy can be explained by either the photon
or ether theory.
To better understand
how, let us consider an example from the sports world.
The Pool Table Example
Image a pool table
that is one hundred feet long and five feet wide. Suppose there is a straight line of pool balls, each touching the
other, on one side of the table on the long axis. This line of pool balls goes from within one foot of the near
side of the pool table to within one foot of the far side of the pool table. In other words, the line of pool balls is
ninety-eight feet long.
Now image that there
are two cue balls on the near end of the table, three inches from the near
cushion. One of the cue balls is lined
up with the long line of pool balls and the other one has no pool balls between
it and the far cushion, almost a hundred feet away. Let us assume that the last of the pool balls in the long line of
pool balls is also a cue ball.
Let us assume the cue
ball in the long line of pool balls is hit by a man, and the other cue ball is
hit by a woman. The cue ball that is
hit by the male pool player only goes a few inches, but the last of the pool
balls in the long line, which is also a cue ball, hits the far cushion.
Now suppose there is
a curtain at the far end of the pool table that is six inches from the far
cushion, such that no part of the pool table can be seen (by someone behind the
curtain) except for the last six inches of the pool table.
See the graphic on
the next page:
Given the same amount
of energy from the two pool players, the long line of pool balls will cause a
ball to hit the far cushion much more quickly than the cue ball that has to
travel the entire distance. And with
more energy, given the same hit of the two pool players.
Now let us suppose
there is a judge at the far end of the pool table who can only see the last six
inches of the pool table because of the curtain. Now suppose that the two pool players each hits their cue ball at
such an energy level and with such timing, that both the woman's cue ball and
the last of the pool balls in the long line, which is also a cue ball, hit the
far cushion at exactly the same time and with the same energy level (i.e. the
same velocity in this case).
How can the judge
behind the curtain tell which cue ball was hit by the man (i.e. the cue ball
that resulted indirectly from the man's hit) or was hit by the woman? The judge cannot tell.
The long line of pool
balls (i.e. the "wave") obviously represents the ether theory of
light. The single cue ball (i.e. the
"particle") hit by the woman represents the photon theory of light.
This simple example
contains a very profound message: since the long line of pool balls (the
"wave") is composed
exclusively of "particles" (i.e. pool balls), the long
line of pool balls has "particle" properties identical to the
"particle" properties of the cue ball hit by the woman!
In fact it is impossible to tell which pool ball is the "wave"
cue ball (from the long line of pool balls) or which is the
"particle" cue ball (the cue ball that travels the entire distance).
Of course, the actual
"bumping" of contiguous ethons is exclusively electromagnetic, not
physical, thus the many properties of pool balls and ethons, such as the
dispersion properties of pool balls versus light, would not necessarily be the
same.
But there is another
serious problem with the Compton Effect:
Problems With
Determining How Light Travels
If an equal amount of
energy is observed resulting from the two pool players (at the far cushion), it
is impossible for the judge to distinguish between which energy level resulted
from the "wave" of pool balls and which resulted from the
"particle" cue ball. But what
if the judge could observe the energy applied by both the man and the woman,
and the judge could observe how much energy is applied to the far wall?
For example, if both
the man and the woman hit their respective balls with an equal amount of
energy, then the amount of energy at the far wall will be stronger for the long
line of pool balls. Thus, if the judge
knows that both cue balls are hit with the same energy level, and if the judge
understands that one cue ball travels the entire distance by itself, and the
other cue ball hits a long line of pool balls, then the judge, based on his own
experiments, can tell which side of the table the long line of pool balls is on!
Likewise, if the
judge knows that both energy levels at the far cushion are equal, but the judge
knows how much energy, and when, each pool player hit their respective cue
ball, then the judge can tell which side of the table has the long line of pool
balls.
In short, because the
long line of pool balls is more efficient than the single cue ball, that has to
travel the entire distance by itself, then knowing how much energy is exerted
and how much energy is measured at the end of the table will tell the judge
which side of the table has the long line of pool balls.
With this in mind, it
should be easy to determine whether light travels by photons or ether. Unfortunately, it is not as easy as it
sounds.
With the pool table
example, we can do simple experiments to determine, under specific conditions,
just how efficient the long line of pool balls is, compared to the woman’s
efforts. We don’t have that luxury with
light because we cannot calculate how efficient ether would be compared to
photons because:
1) If ether exists, we cannot create photons
for our experiments, nor can we create an "ether vacuum" for our
photons to travel through, or
2) If photons exist, we cannot create ether for
our experiments.
In other words, we
cannot compare them both side-by-side because both of them do not exist. To elaborate, whether light travels by
photons or a chain reaction inside of ether, the energy that hits an atom (such
as in the Compton Effect) is an "electromagnetic" energy, not a physical
or mechanical energy. It is also a
wave, since photons are claimed to have wave properties also. How is it possible to theoretically
calculate the efficiency of an electromagnetic jolt from a free flying particle
(i.e. a photon) versus an electromagnetic jolt from a chain reaction of charges
that travel in the ether? We only have
a single final number, but that single final number does not tell us anything
because we have no number to compare it to.
As with the
photoelectric, there is really nothing about the Compton Effect, except
assumptions, that helps us determine whether light is a particle or a signal.
Blackbody Radiation
In the photon theory
of light, each photon is a small “light quanta,” or particle of light. Thus each photon is discrete in nature. One of the experiments that was felt to
demonstrate the discrete nature of light energy was the "blackbody
radiation" or "cavity radiation" experiment.
The blackbody
radiation experiment consists of a metal box, completely enclosed, but with a
small window on it so someone can see inside.
The box is slowly heated up and the observer can see the colors in the
box change as the box heats up. The
term "blackbody" refers to the color of the inside of the metal box,
the term "radiation" refers to the light that is emitted as the box
heats up.
The phenomenon of
blackbody radiation was not discovered by Max Planck, in fact he was not the
first person to work on the formulas for blackbody radiation. Many scientists studied the blackbody
radiation experiments, but no one was able to come up with a formula that would
accurately predict the entire frequency distribution of the blackbody spectrum
for any temperature.
The first to have
some success at predicting this distribution were John Rayleigh and James
Jeans. The Rayleigh-Jeans formula was
based on classical theory. The formula
worked well for the lower frequencies, but since they used an exponential
function, the function did not work well at the higher frequencies. This is because a typical blackbody
radiation distribution curve looks like a distorted "bell" curve,
thus at the higher frequencies, instead of an exponential rise, the curve
drops.
Their formulas were
vastly improved by Wilhelm Weir, whose formulas worked well at the higher frequencies,
but were not exactly correct at the lower frequencies. Max Planck made a very minor, but profound,
change to the Weir formula and was successful at matching the entire frequency
distribution.[22-Chapter 4]
But a formula does
not explain "why" something happens the way it does. Upon a great deal of further analysis,
Planck concluded that the formula worked because light had quantum or discrete
energy levels (i.e. he concluded that light frequencies are
continuous, but their energy levels are discrete). His discovery was not well received at
first. But Einstein took him seriously
and came up with the "little box" thought experiment to justify both
his own belief in photons (according to some researchers Einstein had disavowed
the ether theory in the 1890s) and the discrete nature of light that Planck had
discovered.
Einstein pictured in
his mind a "little box" that had a small hole in one side, that was
placed inside of Planck's big blackbody radiation box. Einstein imagined that individual light
particles randomly went into and out of this "little box," thus
creating discrete energy levels within the little box. In other words, if there were only a handful
of photons in the box, the movement of a single photon into or out of the
little box would cause discrete changes in the energy level inside the box (I
am simplifying his arguments).
As a purely academic
matter, Einstein's "little box" would have to be much smaller than a
single hydrogen atom, and perhaps smaller than a single electron, to contain
only a few photons. If the "little
box" was one cubic centimeter (and the hole was proportionally sized),
many, many photons would be going into and out of the little box at any given
time. In this case the movement of a
single photon would not have been detectable by Planck.
In other words,
Planck's crude equipment could not detect the movement of a single photon; it
could only detect the average, simultaneous motion of many, many trillions of
photons. And even then, it was the
formula, not any observed phenomenon by Planck, that pointed towards discrete
energy levels. In other words, the
discrete nature of photons could not have been the cause of the discrete energy
in the experiment because there were far too many photons (assuming the photon
theory) for his equipment to detect the result of the motion of individual
photons.
To understand more about discrete energy levels, let us
continue the pool table example. Let us
suppose there is a machine that can hit cue balls. Suppose this machine has a finite number of settings, say 100
different energy settings. In other
words, the machine can only hit a cue ball with one of 100 different energy
levels.
Let us put this machine behind the cue ball that is lined up
with the long line of pool
balls. Here is the question: "how
many different energy levels will be observed by the judge at the far end of
the table if we use the machine to hit the cue ball lined up with the long line
of pool balls?" If the machine has
100 settings, the judge will only observe 100 different energy levels of
arriving cue balls, even if we do the experiment a million times.
If atoms only
generate a finite number of energy levels, meaning if there are only a finite
number of possible electron drops from high quantum levels to lower quantum
levels, then why would anyone expect that if light travels via ether that light
would have a continuous number of different energy levels? It is interesting that light has continuous
wavelengths, but there are only a finite number of possible quantum drops.
There are three items
that control whether a type of energy is perceived to be continuous or
discrete:
The
1) "energy source"
generates the energy (i.e. the electrons in atoms) and transfers the energy to
an ...
2) "energy carrier," which
carries and transfers the energy (i.e. the photon or ether) until an ...
3) "energy detector or absorber"
calculates or absorbs the arriving energy level (this would be a spectroscope
in the case of Planck's blackbody radiation experiment).
If all three of these
items can handle continuous energy, then the energy detector may
observe continuous energy levels (i.e. the formula that describes the resulting
distributions may be consistent with continuous functions). If any one of these items can only handle
discrete or finite levels of energy, then only discrete energy levels, meaning
a finite number of energy levels, will result.
Einstein focused his
attention on the "energy carrier," however; it is currently accepted
that the "energy source," namely atoms, can only provide discrete
energy levels. Thus, even if a photon
or an ethon could carry a continuous number of energy levels (and why couldn’t
they?), only a discrete or finite number of energy levels would be observed
whether light travels by photons or ether.
It is absolutely
incredible that blackbody radiation was used as a "proof" of the
photon theory when Bohr's model for quantum electron levels (1913) was
developed long before the photon theory was accepted in 1924. At the time Bohr came up with his first
model, the ether theory was still well entrenched in the scientific world. Thus it should have surprised no one that
the "energy source" was a discrete energy source, and thus it should
be expected that discrete energy levels would be observed. How can a discrete energy level be converted
into a continuum? It can't unless there
are averages of many, many individual events.
No matter whether
light is photons or ether, what goes on inside of the blackbody box involves
many, many photons or many, many signals, thus how does blackbody radiation
prove anything about light?
Is it possible a
particle can "carry" a continuous number of energy levels? We just saw that with the pool table
example. If a human hits one of the cue
balls, a continuous number of energy levels will be transferred by either of
the cue balls. On the other hand, if a
machine with only a finite number of energy levels hits either of the cue
balls, then only a discrete number of different energy levels will be
transferred by either cue ball.
Let us look at
another wave example. Let us consider a
guitar being played by a robot. Suppose
the robot has the ability to pinch or press the guitar strings anywhere on the "neck"
of the guitar (i.e. at a continuous number of points). But suppose the robot can only pluck the
strings with any one of 20 different energy levels. In other words, the robot can play a continuous number of
different frequencies but only with a finite number of different energy levels.
We now have these items
to consider (in parenthesis is a note whether this item can handle a
"discrete" or "continuous" number of frequencies and energy
levels):
1) The robots
"fingers" (discrete energy levels, continuous frequencies),
2) The guitar
strings, which is the "energy source" (continuous wave for both, if
played by a human),
3) The air, which is
the "energy carrier" for sound (continuous wave for both), and
4) Our ears, which is
the "energy detector" (continuous wave for both).
Every item in the
list can handle a continuous number of different frequencies and energy levels,
except for item number one.
But note in this case
that it is not the "energy source" (i.e. the strings), nor the
"energy carrier," (i.e. the air), nor the "energy detector”
(i.e. our ears) that causes the discrete number of different energy
levels! All three of these things can
handle continuous energy levels and continuous frequencies. It is something related to the experiment
(i.e. the robot) that causes the discrete energy levels. Thus we see that there is a fourth thing
that can cause discrete energy levels - the physical facilities and environment
of the experiment.
Suppose, for example,
that atoms (the "energy source") can create continuous energy levels
(which they apparently can't) and that photons or ethons can carry continuous
energy levels and that the spectroscope can handle continuous energy
levels. Is there a possibility that
some physical aspect of the blackbody experiment itself caused the discrete
energy levels?
With all of this in
mind, I quote from an email I received from Dr. Howard C. Hayden, Emeritus
Professor of Physics, University of Connecticut, and former Editor of Galilean
Electrodynamics:
"Thermodynamicists
looked at the blackbody curve (the data) and noticed the similarity to speed
distributions in a gas. They tried to
rig up a similar model to explain the blackbody curve. Nothing worked. One model fit the data at the red end of the spectrum but would
end up with the ultraviolet catastrophe (infinite power at that end of the
spectrum). Another model fit the blue
end but failed at the red end. Along
came Planck. Textbooks say he invoked
E=nhf, but I don't think that's what he was thinking. It is more reasonable, to me at least, that he regarded the
cavity as a resonant cavity, in which the diameter would be one wavelength, two
wavelengths, etc., corresponding to f, 2f, 3f, etc. The BASIC physics he was using was resonance, and the DERIVED
physics was E=nhf, where the f is merely the lowest frequency; more generally
it would be E=hf. When Einstein
proposed his solution for the photoelectric effect, Planck objected
strenuously. The objection is obvious. Planck never meant for the E-M field to be
quantized outside the cavity. Bohr
seized upon Einstein's idea as a way to explain the hydrogen atom. So, in the picture you paint, the metal in
the photoelectric effect is a quantum system, and the hydrogen atom is
also. However, there is no reason for
the E-M field itself to be quantized.
At the very least, the experiments do not prove that it is."