- Albert Einstein was awarded the 1921 Nobel Prize
in physics for the photoelectric effect.
But why?
At the time, just like now,
Einstein was far more famous for his work on relativity.
Well, it all has to do with a man named Philipp Lenard,
who's experiments in the photoelectric effect,
inspired Einstein's theories.
Lenard is a fascinating person
who first inspired and befriended Einstein,
and then due to an odd combination
of his love of physics, scientific disappointments,
nationalism, and mental weakness,
became one of Einstein's greatest nemeses.
This is a physics story and a story of a man's descent
into madness and fascism.
So buckle up and let's go.
♪ Electricity, electricity ♪
A young German scientist named Heinrich Hertz
discovered the photoelectric effect in May of 1887.
See Hertz had just discovered radio waves
by adding an antenna to an induction coil.
So that large sparks in one end of the room
could be caught by making little sparks
in a receiving coil a distance away.
Because the spark in the receiving coil was really small,
Hertz decided to put it in a dark box
so that the light from the bright spark
from the induction coil wouldn't distract it.
To his surprise when he did this,
the spark and the receiver became quote
"Decidedly smaller."
Hertz started to put all sorts of screens
between his transmitting spark and his receiving spark.
And found that glass would reduce the spark,
but quartz did not, as glass blocks ultraviolet light
and quartz does not.
Hertz decided that the energy from the ultraviolet light
must be amplifying the electric spark.
Aside from that one observation,
Hertz didn't attempt to, quote
"Any theory respecting the manner
in which the observed phenomenon are brought about."
This was eventually called the photoelectric effect.
Photo for light, electric for, well electric.
Although Hertz didn't come up with any theories,
many other people tried.
Including a 27 year old Hungarian grad student
of German descent named Philipp Lenard,
who was struggling to get a permanent position.
At the time in Germany, 27 was considered quite old
not to have a permanent position in physics.
I know.
Anyway, Lenard observed that when smooth metal plates
were hit with strong ultraviolet light,
they started looking a little less smooth.
Lenard had this interesting theory
that the electricity could only be carried by dust,
not by gases.
And that the UV light was freeing the dust,
which caused the plates to look rough.
This theory was roundly ignored by basically everyone
and seemed to go nowhere.
However, three years later, Lenard's luck changed
as he managed to get a job as an assistant to his hero,
Heinrich Hertz.
At the time Hertz was studying cathode rays,
or invisible rays that are made in a vacuum,
and can make phosphorus glow.
Hertz found that cathode rays
could travel through thin pieces of metal,
and he told Lenard to make a vacuum tube
with an aluminum barrier.
You might ask why Hertz didn't do the experiment himself.
It was probably because Hertz
was starting to get terrible headaches
and feel sick all of the time.
Left alone in the laboratory,
Lenard not only studied cathode rays
with an aluminum barrier between different vacuums,
he also took it a step further and made an aluminum window
between the vacuum tube and the air,
and found to his surprise, the cathode rays could travel
a few inches in air.
Lenard was sure that his Lenard Tube would finally
make his name in science,
and he published his results in December of 1893.
Tragically Hertz died mere weeks later,
and Lenard took time off his research
to edit German and English memorials
of Hertz's work and biographies.
This was an unfortunate timing for a distraction for Lenard,
as just the next year another German scientist
named Wilhelm Roentgen was experimenting with a Lenard Tube
with a heavier phosphorus and screen
and discovered a new ray which Roentgen called x-ray.
Suddenly the whole world was in an x-ray craze.
At first Lenard was excited by this discovery
and wrote Roentgen a nice letter, quote
"Because your remarkable discovery
caused such remarkable attention in the farthest circles,
my modest work has also come into the limelight."
And at first Lenard was correct,
as they both started receiving numerous medals,
including the Rumford Medal in England
and the Matteucci Medal in Italy.
Lenard finally got an associate professor position,
and after setting up his laboratory
decided to get married.
As he put it, quote
"There was an abundance of daughters of professors
who were waiting to be married."
Soon he was made a full professor
and his career and family life seemed secure.
However, in 1897, an Englishman named JJ Thomson
proved that the cathode ray wasn't a type of light at all,
but was instead a beam of charged particles
that we now call electrons.
With the discovery of the electron,
Lenard found that all of his work on the cathode ray
was made moot.
Even worse, if the cathode ray was a particle
and the x-ray was a beam of ultra, ultra violet light,
which is what we now think, then Lenard's discovery
that cathode rays could travel in air,
had very little to do
with Roentgen's discovery of the x-ray.
In other words, Lenard thought
that Roentgen had just discovered
a new type of cathode ray in air,
but really Roentgen had discovered something new
and Lenard hadn't.
It was a crushing defeat.
Lenard repeated JJ Thomson's experiments
and found that yep, quote
"In every respect, the rays behave like moving masses,
carrying negative charge."
Then Lenard had an ingenious idea.
What if his old theory,
that charges were only carried by dust was right,
if the dust was really just electrons or cathode rays.
In October of 1899,
Lenard published
"The generation of cathode rays with ultraviolet light."
Where he demonstrated that ultraviolet light
produced electrons by shining ultraviolet light
through a quartz screen into a vacuum tube,
and studying the photo electric ray inside the tube.
Unfortunately for Lenard,
JJ Thomson published similar results about the same time.
So he felt like he didn't get the acknowledgement
for that discovery.
Then, what should have been a breakthrough
to understanding the photoelectric effect,
happened in December of 1900.
That is when a German scientist named Max Planck
published his equations for black-body radiation,
where he assumed that light came in little energy elements
with energy equal to a constant
times the frequency of light.
This would explain why ultraviolet light
could have the energy to produce the photoelectric effect,
but visible light did not.
As ultraviolet light has higher frequency
and therefore is composed of elements of higher energy.
However, Lenard didn't see the connection,
and frankly, neither did Planck.
Meanwhile, in 1901, the Nobel decided
to give the very first prize in physics
to Roentgen for discovering the x-ray
without mentioning Lenard at all.
Lenard was very upset and pushed everywhere
that he was unfairly treated.
Determined to make his mark some other way,
Lenard continued to study the particles
created by ultraviolet light in a vacuum tube.
Lenard found that if he added a voltage the wrong way,
he could drive the electrons back to the irradiated plate,
quote "In the same way
as a stone thrown upward falls back to the ground."
Now he could experimentally add just enough voltage
to drive back the electrons and therefore measure
the maximum energy of the electron.
Which is obviously related to the speed of the electron.
To his surprise, the initial velocities
are independent of the intensity of the light.
In other words, more intense light created more electrons,
but it didn't give the individual electrons more energy.
What did this mean?
Well, Lenard had an interesting,
but it turned out wrong, conclusion.
Lenard thought that since the speed of the electrons
was independent of the intensity of light,
that the energy didn't come from the light at all.
Instead he thought the light released energy inherent
in the molecule, like, quote
"The fuse in firing a loaded gun."
This triggering theory was generally accepted as true.
And even as late as 1909,
was written as one of the generally accepted
laws of physics.
Then in 1905 three events drastically changed Lenard's life.
The first was that Lenard was awarded the Nobel Prize
in physics for his work in cathode rays.
This, despite the fact
that 14 top scientists nominated JJ Thomson
for discovering the electron,
and only two scientists nominated Lenard.
Don't worry, Thomson won it the next year.
In his speech accepting the award
Lenard freely acknowledged the work of others,
including many Jewish scientists
and admitted that he wasn't always the person
who brought ideas to fruition,
saying, quote
"I have by no means always numbered among those
who plucked the fruit, but I've repeatedly
been only one of those who planted or cared for the trees."
The second event was in June of 1905.
A patent clerk published a paper
where he proposed looking at many phenomenon,
including the photoelectric effect,
if light came in little energy packets.
This view of light led to a photoelectric effect equation,
which worked with Lenard's results,
but were not proven by them.
The third event was in that same miracle year.
Einstein published a paper on special relativity.
At first, Einstein and his ideas didn't offend Lenard.
In fact, Lenard, or possibly an assistant,
saw how often Einstein referred to Lenard's work
and sent him a copy of his latest paper.
Einstein replied with an enthusiastic letter in return.
It took Lenard four years to reply to Einstein.
But when he did, he was effusive with his praise,
especially considering that Lenard
was a Nobel Prize winning physicist
and Einstein was virtually unknown.
Lenard gushed quote
"What could be more exciting for me
than when a profound, comprehensive thinker like you,
finds favor with some points from my work."
Around this time, 1909, Einstein learned
that a friend of his, Jacob Laub had gotten a position
as an assistant to Lenard.
Einstein wrote Laub, quote
"I think the opportunity to work with Lenard
is worth far more than the assistantship
and income combined.
Lenard is a great master and an inventive thinker."
However, Laub's relationship with Lenard quickly soured,
and Einstein's went with it.
See Lenard was a big believer in something called the ether,
an invisible weightless material
that fills the entire universe, even in a vacuum.
So that light will have something to vibrate.
After all they thought, if you have a wave,
you need to have a wave in something.
In fact Lenard insisted that electrons
were really just pieces of ether.
However, by 1910, this magical material was losing ground
because of Einstein and relativity,
as the odd effects attributed to the ether
could just be because of the limitations
of the speed of light.
Laub complained to Einstein
that Lenard was wasting his time on useless experiments.
Einstein wrote back, quote
"Lenard's recent lecture on these fanciful ethers
appears to me almost infantile.
Further the study he commanded of you borders on the absurd.
I'm sorry you must spend your time on such stupidity."
Einstein tried to get Laub a new position,
which earned Lenard's ire for both men.
Lenard started treating Laub very cruelly,
and when Einstein heard of it, he wrote Laub, quote
"Lenard is really a twisted fellow.
So entirely composed of gall and intrigue,
however, you're considerably better off than him.
You can get away from him.
However, he must do business with this monster
until he bites the dust."
Then, in 1914, an American named Robert Millikan
published his work on the photoelectric effect,
that he had started to disprove Einstein,
but had shockingly confirmed every detail
of Einstein's photoelectric equation.
The triggering theory was completely destroyed.
In addition, that same year
was the beginning of World War I,
which Lenard was a vocal German supporter.
In fact, Lenard signed the manifesto to the civilized world,
which included the line "Without German militarism,
German civilization will be wiped off
the face of the earth."
Not only did Einstein refuse to sign the manifesto,
he co-wrote a rebuttal.
When Germany lost the war, Lenard was devastated.
And to make matters worse, that very same year,
an English astronomer used the solar eclipse
to prove that gravity could bend light.
In other words, he experimentally proved relativity.
Einstein became the most famous physicists in the world,
and most scientists believed in relativity.
Jealous and heartbroken, Lenard decided
that it was all because Einstein was Jewish
and it was a big Jewish conspiracy,
to get rid of ether, push relativity,
quantize the photoelectric effect,
destroy Germany and discredit him.
Lenard made it his life work
to remove Jewish science from Germany.
He tried to keep all positions for pure Germans,
and he also used his influence with the Nobel committee
as a previous winner,
to try to up keep Einstein from joining their ranks.
In 1919, Lenard managed to get his friend
and fellow anti-Semite Johannes Stark, a Nobel Prize.
Despite the fact that Lenard
was his one and only nominator that year.
By 1920 Lenard was heading the anti Einstein
and anti relativity groups with speeches,
debates and anti-Semitic publications.
The 1921 Nobel committee became so confused
by the pro and anti relativity factions,
they didn't give anyone a Nobel Prize that year.
The next year, a young Swedish scientist named
Carl Oseen found a way around the whole mess
and suggested that Einstein
should win the Nobel Prize for the previous year, quote
"Especially for his discovery
of the law of the photoelectric effect."
Then Lenard went completely off the rails.
By 1924, Lenard was a devoted fascist,
and he and Stark published an article
in the newspaper saying, quote
"Hitler and his comrades appear to us as God's gift
from the times of old when races were pure."
By the 1930's Lenard started publishing books
of science separated by their races,
which became the backbone of Nazi science.
In 1933, Einstein fled Germany never to return.
Lenard prided in how he drove Einstein
and other Jewish scientists out of Germany,
and had all Jewish work burnt.
Although he would have preferred their death,
ranting to Stark that "More than ever, the Jews
must be sunk right down to the center of the earth."
Ironically, without their boogeyman,
Lenard and Stark start to lose
their appeal to the Nazi elite.
They could not help with the war effort,
and obviously they could not help with vision studies.
In addition, by this time, Lenard was getting old,
and the Nazis fundamentally did not respect the elderly
and unattractive Lenard as compared to other scientists,
like the handsome and youthful Heisenberg.
Lenard survived the war and died in 1947 of old age.
Whew, good riddance.
Let's go back a bit to Einstein and his 1905 paper
on the photoelectric effect.
Actually it wasn't really just on the photoelectric effect.
Einstein's 1905 paper was on the new view of light
where the photoelectric effect was just one example
of how this new view of light could explain the experiments.
But what was Einstein's new view of light?
Why was it so transformative and radical?
That's next time on the Lightening Tamers.
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