Einstein’s Revolution: Crash Course History of Science #32

There was physics before Einstein… in the
same way that there was biology before Darwin.
Einstein didn’t just add some new ideas
to physics. And he didn’t just add a unifying
framework for doing physics, like Newton.
Einstein took what people thought was physics,
turned it upside down, then turned it inside
In the same way Darwin’s work made people
see life itself differently, Einstein’s
work made humanity reexamine time and space.
[Intro Music Plays]
The classical worldview—associated with
names you know, like Euclid, Aristotle, and
Newton—held that the rules governing space
and time were absolute. One meter was always
one meter long; one hour would always be one
hour long…
Matter was made up of immutable and indivisible
And energy moved through a medium called ether—because
everything had to move through something,
right? God wouldn’t just make, I dunno,
a howling void?
And with new disciplines like thermodynamics
and fun applications like steam power and
light bulbs, human understanding of the fundamental
forces of nature seemed pretty solid.
To quote historian of science Milena Wazeck, by 1900, “physics
was perceived by many to be an almost completed
But within this almost-completeness lurked
many unanswered questions. One of the biggest
was the failure of the Michelson–Morley
experiment in 1887. They’d attempted to
demonstrate that the speed of light changed
just a little when measured from the earth,
which is always moving, relative to the ether,
which never moves.
But despite meticulous efforts, they couldn’t
find any slowing-down. Light moved at a constant
speed—almost as if there was no ether.
Then there was the electron and radioactivity.
In 1897, English physicist J. J. Thomson showed
that cathode rays were made up of discrete
particles, way smaller than whole atoms—electrons.
And around the same time, Marie Curie proposed
the theory of radioactivity, which classical
physics didn’t predict.
Then, in the early 1900s, Ernest Rutherford
experimented on radioactive decay. He named
radioactive alpha, beta, and gamma particles,
classifying them by their ability to penetrate
different kinds of matter.
And Henri Becquerel measured
beta particles and realized they were actually
electrons exiting the nuclei of atoms at high
So by the early 1900s, radioactive decay was
understood, and the crisis of the immutable
atom was as deep as the crisis of the ether.
A bunch of folks were investigating Maxwell’s
equations and looking at black-body radiation,
or the heat emitted by dark objects when they
absorb light.
Then Heinrich Hertz, the original radio wave
guy, discovered the photoelectric effect,
or the paradox that certain metals produce
electrical currents when zapped with wavelengths
of light above a certain threshold.
Things started to get messy. Energy was thought
to be a continuous wave. But according to
wave-based theory, there might be infinite
energy radiated back by black bodies zapped
with certain wavelengths. This seemingly violated
the newly established laws of thermodynamics. Like, infinite energy doesn’t seem right.
So, in trying to explain the weird results
about light and heat, German physicist Max
Planck theorized that light
may not be a wave after all, but a series
of particles or quantum units. All very non-“classical.”
Sorry, Aristotle!
Check out Crash Course: Physics for more about
quantum weirdness!
Enter Albert.
Einstein was born in 1879 and grew up in southern
Germany, Italy, and Switzerland. He dropped
out of high school, then studied to teach
physics and math and became a Swiss citizen.
But he couldn’t get a teaching job—because
he was Jewish.
So in 1901 he took a job at the patent office
and started a Ph.D. at the University of Zurich,
which he finished in 1905. You’re going
to want to remember that year…. 1905.
Now, Al wasn’t an academic hotshot or self-funded
amateur. He was a working-class nobody who
did physics on the side. But he was also a
patent officer who spent his days pouring
over technical documents.
He was an outsider obsessed with math because
math is beautiful, and yet he was a deeply
practical person who believed that good math
and science could be communicated plainly.
Plus, he was young and bold. And he had a
super smart and supportive first wife, Serbian
mathematician Mileva Marić.
So, the year he finished his Ph.D., 1905,
Al published his dissertation and four papers
that changed physics overnight. This was his
annus mirabilis or miracle year, like 1666 had been for Newton.
Help us out, ThoughtBubble.
At age twenty six, Einstein published revolutionary
work on:
1. Brownian motion, or the random motion of particles
in fluids;
2. the photoelectric effect, supporting the idea
of energy as a series of particles, not a wave;
3. the equivalence of mass and energy; and
4.special relativity.
Special relativity, especially made Einstein
a scientific rock star. He proved that nothing
can move faster than light. This explained
why Michelson and Morley hadn’t observed
light slowing in ether. And a lot of other things.
Einstein got rid of all reference frames for
space and time. There was no longer some universal
space in which physics happened. All measurements
became relative to the position and speed
of the observer.
Space and time became one mathematically continuous
spacetime. So an event at one time for observer
A could take place at a completely different
time for observer B.
And the only constant in the entire system
became the speed of light—which classical
physics predicted could change!
From special relativity followed the equivalence
of mass and energy proof. Which was also mind-blowing.
It’s probably the most memorable physics
formula ever, since it’s printed on mugs
and T-shirts the world over: E=mc2. Or,
energy equals mass times the speed of light,
squared. Or, mass and energy can be converted
into each other!
Or, as Einstein said: “…mass and energy
are both but different manifestations of the
same thing—a somewhat unfamiliar conception
for the average mind.”
Now, it’s important to note that Einstein’s
new system of physics is simply a different
system than Netwon’s. “Mass” and “energy”
mean something different in the two systems—because,
to put it bluntly, Newton’s system turns
out to be not so universal. It only seems
to work on earth, because we aren’t particularly
massive or fast-moving, compared to stars.
Thanks Thought Bubble. We don’t have time
to explain all of the cool science that Einstein
and his generation of physicists did around
World War One, but two things stand out:
In 1915, Einstein published the theory of
general relativity. Special relativity was
all about comparing physical effects from
different observer positions in terms of velocity,
or speed in a particular direction.
General relativity provided all of the complicated
math regarding relativity and acceleration,
or speeding up or down.
General relativity explains the physics of
all situations. Special relativity is one
specific case of general relativity.
General relativity nailed the coffin shut
on the classical, Euclidean worldview: now gravity
itself was shown not to be a force like light,
but an effect, a distortion in the shape of
space due to mass…
So the planets didn’t follow certain paths
because of the attraction of the sun’s gravity,
but because the space before them was curved
by the sun’s mass.
Einstein’s universe wasn’t a series of
perfect spheres in an ether, but a void whose
very dimensions—whose rules, basically,
other than the speed of light—could change.
Many of his colleagues initially objected
to this, but Einstein was confident—and
patient. Astronomers awaited a solar eclipse
in 1919, that allowed them to experimentally
confirm Einstein’s theory.
The confirmation of gravitational lensing made
Einstein a scientific hero and an icon of
pop culture. As The Times of London reported,
“Newtonian Ideas Overthrown.”
The second major act of science Einstein did
around World War One was contribute to the
birth of modern particle physics. This story
is about, in part, Einstein getting it wrong.
In 1911, Ernest Rutherford and Danish physicist
Niels Bohr [“NEELS BOAR”] theorized a
model of the atom with electrons zipping around
a heavy nucleus. Scientists began to study
the physics of the very small, just as Einstein
was working out the physics of the very large.
But over the 1920s, these particle physicists
saw a lot of weird quantum or particle-like
Basically, Bohr’s Copenhagen group showed
that very small particles tend to act like
particles sometimes but like waves at other
times. Like waves, their behaviors have probabilities.
But when measured, individual particles are,
well particles. They are or aren’t there.
In 1926, two German physicists worked out
the math behind these quantum mechanics: Werner
Heisenberg invented matrix mechanics, which
[large exhale] are complex and Erwin Schrödinger,
wave mechanics. And lots of dead/not-dead
cat jokes.
Because, in 1927, Heisenberg proposed his
uncertainty principle: any observer can detect
the position or velocity of any quantum particle,
at any given time interval, but not both at
the same time.
Einstein haaated this. He believed in a universe
ordered by an ultimate rationality, and he
famously quipped, “God doesn’t play dice
with the world.” But Al, who had contributed
in lots of ways to the emerging model of atoms
and particles of energy, was wrong about uncertainty.
By the 1930s, Einstein was easily the most
famous scientist since Darwin. There was just
one problem. He was still Jewish. And living
in Germany.
So in 1933, Einstein renounced his German
citizenship and took a professorship at Princeton.
As a celebrity genius with intimate knowledge
of the cutting-edge of German science—and
perfect hair—Einstein had the ears of politicians
anxiously planning for another great war in
And, after one of his physicist buddies demonstrated
that an atom could be straight-up, stone-cold
split open, Einstein felt that he had a moral
obligation to explain to the American establishment
just how powerful atomic energy could be…
We’ll pick up this thread next time.
Suffice to say, World War Two eventually ended,
and a new Cold War started—with scientific
discovery, especially in the physics that
Einstein had created, as the new measuring
stick of imperial might.
Israel offered Einstein the presidency, which
he turned down. He lived the rest of his life
in the home of technological innovation and
“fat sandwiches”—New Jersey.
Einstein always regretted that his work was
used for violent ends. In fact, he was generally
skeptical of modernity. Way back during World
War One, he wrote: “Our entire much-praised
technological progress, and civilization generally,
could be compared to an axe in the hand of
a pathological criminal.”
And yet, in the end, even the horrors of two
world wars never shook his faith that there
was great meaning in the universe—a code
to be deciphered by science.
He died never quite accepting quantum randomness,
and believing that, one day, humans would
crack the code.
Next time—the Americans use Einstein’s
world-threatening Bomb, and warfare changes
forever. It’s the birth of nuclear physics,
the end of World War Two, and the beginning
of the Cold War.
Crash Course History of Science is filmed in the Dr. Cheryl C. Kinney studio
in Missoula, MT and it’s made possible with the help of all these nice people.
And our animation team is Thought Cafe.
Crash Course is a Complexly production. If you wanna keep imagining the world complexly with us,
you can check out some of our other channels like
Scishow, Eons, and Sexplanations.
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100 thoughts on “Einstein’s Revolution: Crash Course History of Science #32”

  1. How about you do an episode on computers, like introducing Turing or Shannon? No mathematician got any love 🙁 I think computers are more affecting our knowledge 😀

  2. Crash Course needs to do Crash Course Spanish. With how well they help me with the other subjects, I'm sure they could make me a fluent spanish speaker too.😂

  3. 7:12 Could someone please explain to me the specific difference in the definition of "force" vs the definition of "effect"?

  4. …infinities [03:10]—creep into mathematics too, but we have ways of dealing with those: Example—the derivative D xⁿ = nxⁿ⁻¹ or equivalently D xⁿ/n = xⁿ⁻¹ for integer n, but it also works for any real number, the derivative D xᵃ/a = xᵃ⁻¹ but now, suppose that a→0 which means D ∞ = x⁻¹ (because xᵃ/a → 1/a → ∞) but we-know D log x = x⁻¹ case-solved QEF…

  5. another nice one.

    BTW it'd be nice if you can show a basic timeline of the events Hank is summarizing, maybe at the bottom of the screen, for us visual learners.
    I love the efficiency of all your content though, because I can Rewind the teacher.

  6. …Einstein was a crowd-pleaser: he made Special Relativity satisfactory for all kinds of physicists, those that wanted co-relativity at-or-despite the speed of light, those that wanted it dependent on emission, those that wanted it dependent on space itself—by introducing his special brand of 'assume-they-also-want-light-mustard with their spacetime'—except for those who wanted the mathematical-A truth…

  7. Wait, you're not going to cover the gold foil experiment? That's even more fun than the double-slit experiment.

  8. Sad face 🙁 at 5:01. Special Relativity doesn't prove "nothing can move faster than light" and it doesn't retroactively explain the null results of the Michelson-Morley experiments. This is backwards, yet unfortunately what is often promulgated in popular explanations. The null results of the M-M experiments in conjunction with, I believe, the Maxwell equations suggest that the speed of light could be constant. Then, assuming that it is – effctively a priori – which is what Einstein did – one can deduce (i.e. prove via propositional logic and algebra) the consequences of that assumption: special relativistic time dilation and length contraction – physical and temporal effects which later empirical experiments have since supported being the case. But dangitall, supposing first that the speed of light is constant is what proves relativity; relativity doesn't prove the speed of light is constant (and that nothing can go faster than it)!

  9. uhh, einstine didnt get a job being a teacher not because he was jewish. he couldnt get a teaching job cause he kept it real and that pissed people off.

  10. Em.. So, "the end of WW2" and nothing about the crisis in math and Gödel, Hilbert's 20 problems, or anything or anyone from XIX – beginning of XX centuries math. Is it that hard to tell a story about math?

  11. When you said Einstein "took up a professorship at Princeton", I think you meant – took up a professorship at the Institute for Advanced Study in Princeton.

  12. Crash Course Not sure why you made it sound like Einstein helped in any way for the making of the A-bomb…

    SMH… That's Disgraceful

  13. If i am not mistaken, Newton did think of light in form of absolute particles, he did a great deal of research in light with this assumption, so i am not sure when you said that the older world view of light was of wave nature only. Also if i remember correctly, people firmly believed in newton"s work on light(that is particulate nature) until Young's Interference experiment in 1801, which changed the view and shifted it towards wave nature.
    PS- i like your content, but i am a huge Newton fan so..

  14. Newton was the Man who explained how Gravity makes things fall

    And Einstein the Man who explained how it didn't!

    Absolute Genius.

  15. I dont think einstein is so important for physics as darwin is for biology

    Evolution seems to be the thing that explains why everything in biology is the way it is. But there is plenty of stuff in physics that you can explain only with newton. I have a degree in physics, and i didnt hear about relativity until the last year

  16. Your pronounciation of "Schrödinger" cracked me up :'D Anglophones are notorious for not even trying but we do kind of love you for it too 🙂

  17. "Science can create all means but it depends on the nature of the goals for which they are used for …. The fate of humanity is entirely dependent on its moral devellopment." – Albert Einstein

  18. "The economic anarchy of capitalism is the root of all evil." – Albert Einstein

  19. "It's not that I'm so smart, it's just that I stay with problems longer." – Albert Einstein

  20. I wonder what kind of country israel would have been if it's first president had been Albert Einstein. An Atheist who avoided conflict like the plaque. And an icon of science like none before him.

  21. Einstein didn't actually prove that the speed of light is constant, he postulated it, and developed relativity from there, and the assumption that the physical laws of the universe are the same no matter your referencial.
    I know the purpose of the video isn't teaching relativistic physics, but as a future physics teacher I couldn't let this mistake go unnoticed.

  22. Okay, I've been reluctant to ask this because I'm partially color blind, and so I know I don't see colors the way a normal person would. But I finally asked someone else to confirm it, and the portraits of 'Ernest Rutherford' and 'Niels Bohr' are seriously wrong. You've been doing this throughout the series, and I have to ask. WHY DO YOU DO THIS???

  23. I have an unrelated question. What is the story behind those two blue monster looking things on the shelf behind you? My curiosity never ends 🙂

  24. There are 3 lights in the form of a triangle…
    A, B, and C are lights. S1, S2, S3 are spaceships.

    S1 S2

    A S3 C
    S1 is moving from A towards B. S2 is moving from B towards C. S3 is moving from C towards A. A, B, and C flash simultaneously in their frame of reference. So in the frame of reference of S3, A flashes first followed by C flashing. In the frame of reference of S2, C flashes first followed by B flashing. In the frame of reference of S1, B flashes first followed by A flashing. So the sequence of flashing is A, C, B, A. But wait! A flashed first. How can it flash last? How can A flash both first and last?

  25. There is a chain with objects at both ends that are blocking lights L1 and L2. Like this….

    L1 O—————————O L2

    Ok. Now the objects will lower in order to release the light from L1 and L2. For someone in the mid-point of the distance between L1 and L2 and who sees the light from L1 and L2 simultaneously, the objects will lower simultaneously and the chain remains intact. Like this….

    L1 L2

    For someone moving at a high speed towards L2 from L1, the object in front of L2 will lower before the object in front of L1. So we get this…

    L1 O———– L2

    So for the stationary observer with respect to the chain and lights the chain remains intact because both ends lower at the same time. For the moving observer the chain breaks because the end at L2 lowers before the end at L1 which lengthens the distance that the chain must extend.

    So we have a paradox. A chain can't be both broken and intact at the same time.

  26. You're very wrong about the part with the famous "God does not play dice" quote. Einstein was objecting to the idea that the position of a particle is truly random, and not governed by some deterministic process. The problem is that "uncertainty" sounds like "randomness," but that's really a misnomer. Uncertainty would be better called "spread-out-ness." Einstein was not objecting to this spread-out-ness; that kind of uncertainty is a property of waves and is present in classical theories like GR. The idea that Einstein is objecting to is the idea that the waves in question aren't "real" in themselves but instead represent probabilities of truly random (non-deterministic) outcomes, and in particular, the way of interpreting this randomness that became known as "the Copenhagen interpretation."

  27. Well, Einstein's view about QM my ultimately turn out to be right, but only with the cost that the speed of light may not be a limit for all types of happenings after all.

  28. Einstein was a bloody heretic.

    Everyone knows that Mankind travels faster than light by traveling through the warp, nuzzled deep inside a Gellar field, guided by the holy light of the Astronomican.

    In the grimdark equations of the math future, there are only more questions. There is no peace among the disciplines, only an eternity of impossible theory and dogmatic principles. And the laughter of thirsting scientists.


  29. How did he figure all of this out, and how did it change everything so fast? Wasn't he pretty much a nobody in Europe when he published his thesises?

  30. I don't want to be that guy… but both at the time and now a days Einstein gets too much attention and credit. Unfortunately, because he was immediately famous then as well, retroactive analysis cannot ignore the disproportionate impact he had at the time, thus perhaps perpetuating that mythos. Also, quantum physics isn't weird. Humans are weird for not getting it (and telling people it is weird and not something that they can understand/see as the real truth of the world doesn't help fix that paradigm). But that is a science education debate (like why it is quite arguably bad practice to teach students the 'octect rule').

  31. 2:40 "the heat emited by dark objects when they absorve light"

    Is this correct?

    I might be wrong but isn't this description misleading? Since the heat emited itself is light, they are not necessarly dark and because the're other ways to get hot without absorving light?

  32. been binge watching the videos
    They finished :'( .
    I was like WTF!
    Then saw the time stamp.
    Oh last video just 2 weeks ago.
    Now waiting for the new videos.

    Great work keep it up!

  33. Technically Einstein was a professor at the Institute of Advanced Study, not Princeton University per se, although he did teach lectures there.

  34. 2:50 I think it's wavelenghts BELOW a certain threshold. uv light produces electrons while infrared doesnt.

  35. Good video, only missed one thing: Nikola Tesla proved the existence of the aether.

    Changes argument to:
    1. Michelson-Morley Interferometer Experiment of 1887 proves that the heliocentric, spherical model is inconsistent with the existence of the aether
    2. Einstein explains away the aether over the course of 3 papers published from 1905-1915
    3. Tesla (along with Maxwell and Faraday) proved that Einstein's musings are not rooted in proven experimentation like that done by the fathers of the modern electrical grid who engineered several components which require the aether to function at all
    C. If the aether can be proven to exist, then the Earth is actually a Flat Motionless Geocentric Disk with a Dome on top that rotates around the Earth (with the 7 planets of the solar system all moving independent of the dome/star movement–in Latin "planet" means "moving star")

    This is by far the most conclusive proof which nullifies the existence of the globe model. The only other theory that exists which includes both an aether and the globe in light of Michelson-Morley is the "ether drag" theory which can be safely dismissed using the findings from G.B. Airy's 1871 experiment nicknamed "Airy's Failure" (notice how every experiment that proves something related to the classical models of the world like geocentricism is labeled a "failure" by mainstream academia rather than unbiasedly considered as a compelling piece of evidence to the contrary on an unsettled issue). In Airy's Failure, stellar aberration is analyzed to inadvertently prove it is the universe which revolves around the Earth, not the Earth spiraling through the infinite ever expanding vacuum of space. Using this evidence, we can conclusively dismiss the theory of "ether drag" and confirm that the Earth is in actuality a Flat Motionless Geocentric Disk with a rotating dome affixed above it.

    The magnetic poles are structured like that of a disk magnet, not like that of a magnet that does not actually exist in nature (iron rod on axis of suspended spinning sphere). Water always fills a container and finds its level after settling; that is to say that water fills the container to form a flat perfectly level surface after settling. Using this fact, the oceans would make far more sense if they behaved like water in every other circumstance, and the water that composed them found its level rather than curving to stick to a spinning sphere. Look up what happens to a tennis ball if you spin it quickly, does the water stay attached? Gravity is identified as the force that pulls everything into the oblate spheroid that is earth, and despite not being strong enough to overcome the laws of density and buoyancy which govern the type of objects to sink and rise relative to others (allows balloon to float away bc it is less dense, and for us to float to top of pool of water bc we are less dense while brick falls to the bottom because it is more dense than both water and air), it is still somehow able to keep all of the water from flying off the spinning ball that is rotating at 3x the speed of sound. Water doesn't even pull and collect around the equator more than the rest of the ball like one would expect as a result of the centrifugal divergent force acting upon the water…somehow gravity is just so strong it can keep everything in place……..well everything but that balloon.

    Fact check everything I've said. I dare you.

  36. Heisenberg gets pulled over by a policeman. The policeman says, “Sir, are you aware you were going 100 in an 80 zone?” Heisenberg replies, “Great! Now I don’t know where I am!”

  37. Einstein could not get a job – because he pissed off his professors. They would not write recommendations for the poor guy.
    Shock: 4 years of COLLEGE, no Ph.d.!

  38. I like that quote about our tech advances being comparable to an axe in the hands of a psychopath. Very true.

  39. Einstein's role to the development of Quantum Mechanics was crucial!! More than any other and certainly more than Plank and Bohr. 1. In 1905, Einstein proposed the existence of the photon, an elementary particle associated with electromagnetic radiation (light), which was the foundation of quantum theory. 2. In 1907 and again in 1911, Einstein developed the first quantum theory of specific heats by generalizing Planck's law. 3. In 1918, Einstein developed a general theory of the process by which atoms emit and absorb electromagnetic radiation (his A and B coefficients), which is the basis of lasers (stimulated emission) and shaped the development of modern quantum electrodynamics, the best-validated physical theory at present. 4. In 1924, together with Satyendra Nath Bose, Einstein developed the theory of Bose–Einstein statistics and Bose–Einstein condensates, which form the basis for superfluidity, superconductivity, and other phenomena. 5. Even His criticism on Quantum Mechanics was beneficial for us since he pointed out things about QM that others couldn't see, like quantum entanglement (spooky action at a disctance). In 1935, together with Boris Podolsky and Nathan Rosen, Einstein put forward what is now known as the EPR paradox, and argued that the quantum-mechanical wave function must be an incomplete description of the physical world. For those who are interested in this, I suggest this article: Einstein’s Contributions to Quantum Theory∗
    Norbert Straumann
    Institute for Theoretical Physics
    University of Zurich, Switzerland ¨
    February 2, 2008

  40. As a New Jersian and original Princetonian (and big ol nerd), my parents liked to remind me that Einstein didn't wear socks because he thought they were a waste of time. All the police in Princeton also knew him because he kept forgetting where he lived and needed directions back to his house!

  41. Part of the Mcihelson Morley Experiment was to answer the question regarding the existence of an ether. JJ Thomson, Marie Curie, Ernest Rutherford independently made discoveries regarding the particles from the atom and from the nucleus that made them the stars of the season in the field of Physics. Later the names of Becquerel, Hertz, Planck joined the list and soon after, Albert Einstein shook the world with his new theory regarding relativity.

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