The late 1800s and early 1900s saw a revolution
in the very basics of what-is-stuff.
This story features killer rays and a family
of geniuses: it’s the discovery of radioactivity,
the birth of particle physics, and the life
and enduring legacy of Marie Skłodowska Curie.
Now, Nobel Prizes—which started being given
out in Marie’s time—aren’t everything.
But she was the first woman to win one, the
first person to win two of them, the only
woman and one of only four people to win in
two different fields…
And she remains the only person, ever, to
win Nobels in multiple natural sciences.
[INTRO MUSIC PLAYS]
Before we get to Marie, let’s review physics
so far.
Scientists around the world had worked out
the physics of Newton’s universe—in which
large, visible stuff collides due to the invisible
but lawlike action of gravity—as well as
the strange world of thermodynamics and electromagnetism.
Heat is energy!
Radio waves can carry signals around the world!
All weird—and about to get weirder.
In 1895, German engineer Wilhelm Röntgen
was experimenting with making
cathode rays, or rays of electrons.
His device was blacked out.
But he noticed that a piece of cardboard painted
with barium platinocyanide fluoresced, or
glowed, when it was placed near the cathode
ray tube.
This made no sense.
No light meant no glowing… and yet, my dude’s
cardboard glowed.
So Röntgen set up another experiment.
He blacked out the machine, turned the lab’s
lights out…
And saw that the painted board was already
glowing in the dark.
Faintly, sure, but glowing.
The machine wasn’t on.
No known source of energy could have been
producing that spooky light.
So Röntgen threw himself into investigating
what he called “spooky rays” after his
friend, Count Fritz von Spooky.
I'm kidding, he called them X-rays, after the letter
mathematicians use to symbolize unknown variables.
And this phenomenon got spookier when, testing
the rays on different materials and arriving
at lead, Röntgen saw a projection of his
own skeleton!
So he experimented with creating images of
what he was seeing, and at this point made
the now-typical scientist move: he asked his
wife for help.
Because the couple that sciences together,
stays together!
So Anna Bertha Röntgen let her husband make
an image of the bones in her hand using X-rays.
And then Röntgen wrote up his experiments
in a paper called, wait for it, “On a New
Kind of Rays.”
This paper earned him an honorary medical
doctorate, the very first Nobel Prize in Physics,
in 1901, and a place in the hall of fame of
radiology—or using radiation to see the
inside of the body.
In fact, in his day, X-rays were sometimes
called “Röntgen rays.”
In early 1896, at the Academie des sciences,
French physicist Antoine Henri Becquerel heard
about the discovery of X-rays.
Becquerel had been experimenting on phosphorescence,
or hitting materials with light to make them
glow new colors.
He reasoned that maybe some phosphorescence
was related to Röntgen’s X-rays.
So he busted out his inherited supply of his
father’s uranium—yes! seriously, this was a thing.
Thanks, Dad!
Becquerel soon realized using photography
that some materials naturally gave off spooky
rays.
Like, uranium left an impression in a photographic
plate just by being near it.
Some sort of energy was hitting the plate.
This was radiation: energy that comes out
of matter as it decays, or breaks down into
other, smaller forms of matter.
Curie would later name this process of decay
“radioactivity.”
Becquerel dove into research on radioactivity.
He figured out that uranium emits rays that
can be deflected,
or pushed around, by electromagnetism, so
they’re a different form of radiation from
X-rays, which are not affected by electromagnetism
at all.
Becquerel also researched what happens when
you mix radiation and magnetic fields, showing
that radiation can have electrically negative,
positive, or neutral charge.
And he did important work on electrons, which
we’ll get to next time.
Becquerel’s contributions to radiation studies
were wide ranging, from basics to potential
applications.
When he accidentally burned himself by carrying
around a piece of radium, he and other researchers
concluded that radioactive substances might
be able to burn bad stuff like tumors,
so they might have a medical use in fighting
cancer.
This continued the tradition of using radiation
as a medical technique that Röntgen had started
and the Curies would build on.
Becquerel died in 1908, likely due to his
work with radioactive substances.
He was only 55.
He left behind a clear research question:
what happens when matter radiates spooky energy?
Enter Maria Curie, born Marie Skłodowska in Warsaw, at
the time part of the Russian Empire.
Born—to science.
But the Russians outlawed lab science in schools,
and the University of Warsaw didn’t admit
women.
So she went to a secret school called the
Flying University which is totally real and
you should Google.
Then in 1891, she joined her older sister,
Bronisława, in Paris.
They made a pact to help each other finish
degrees.
Marie smashed this goal.
Despite not being great at French, and with
no formal training in the sciences, she enrolled
at the University of Paris, one of the best
schools on earth…
And earned a degree with distinction in physics—basically
a master’s—in 1893 and a second, in mathematics,
in 1894.
At first, she was super broke and hungry.
She tutored all night after her own classes,
and she was barely keeping up.
But then after her first degree, she was hired
to study the relationship between magnetism
and steel for the Society for the Encouragement
of National Industry.
She needed a place to work, and in her search
for a lab, she met Pierre Curie, who taught
at the School of Physics and Chemistry.
And they fell in love over SCIENCE!!!
Pierre proposed, but Marie was like, yeaaah,
I’m from Poland…
The place Germany and Russia have been fighting
over for a thousand years?
Cold!?
I’m moving back.
And you don’t want to do that, right?
But—plot twist—Pierre was like, anything
for you!
Even leaving La Belle Epoque Paris right as
modern art is being born.
Marie said I’ll think about it.
On summer break, she returned to Poland and
went up for a job at the prestigious Jagiellonian
University of Kraków.
But the Jagiellonians were clear: they would
never grant a professorship to a woman, no
matter how brilliant.
So Marie returned to Paris and started a Ph.D.
She also made Pierre finally finish his own
Ph.D., and he was promoted.
He admitted that Marie was “his biggest
discovery.”
Which is pretty sweet.
Well, in 1895, they got hitched.
It was a secular affair.
Marie wore the same clothes she wore to the
lab.
Marie found out about Röntgen’s and Becquerel’s
discoveries and, being trained in the study
of electromagnetism, formulated an experiment.
She used a sensitive electrometer, which measured
electric charge and was developed by Pierre
years earlier,
to test how ray-producing uranium affected
electromagnetic fields.
She found that uranium gave off rays that
made the very air conduct electricity.
Her work also showed that the only thing that
mattered in terms of this effect was how much
uranium was present.
That’s it.
The uranium didn’t have to interact with
anything in order to give off energy and change
electromagnetic fields.
What happened next, ThoughtBubble?
Marie created, for the first time, a theory
of radioactivity: in some substances, atoms
themselves must be breaking down slowly, releasing
energy.
This theory became foundational for modern
physics.
From the Presocratic Atomists to the the creator
of the periodic table, Dmitri Mendeleev, a
long tradition of people studying stuff had
built upon an imaginary indivisible unit of
matter—the atom
—that a woman from Warsaw had just divided.
Radioactive decay clearly violated the immutability
of atoms, so atoms could be split.
Intense foreshadowing!
Oh, and a lot of this work happened between
her marriage in 1895 and the birth of her
first daughter in 1897.
And it happened in a shed.
She scienced in an unventilated room, unaware
of the dangers of handling radioactive substances.
And when I say “she,” I mean it.
She recorded her experiments and her ideas
separate from her belovèd husband’s.
But they increasingly worked together as Pierre
realized that, smart as he was, she wore the
brain pants.
(Err, you know what I mean.)
Here are some highlights:
In 1898, she showed that thorium is radioactive,
around the same time as another scientist,
Carl Schmidt.
Also in 1898, Marie and Pierre discovered
the element polonium, naming it after her
oppressed homeland.
Also in 1898—most famously—she isolated
the radioactive element radium out of uranium
ore.
In fact, she developed techniques for isolating
radioactive isotopes, or forms of the same
element with different properties, which we
now know are due to different amounts of neutrons.
The Curies shared a Nobel Prize with Becquerel
in 1903.
Basically, for discovering that, while most
matter doesn’t decay quickly, some relatively
rare elements do.
And Marie applied her theory.
She used radioactive materials to treat cancer.
Pierre had the idea of implanting small seeds
of radioactive material into tumors to shrink
them.
And when the Great War broke out in 1914,
she set up mobile radiography units, meaning
X-ray systems, to help field doctors treat
soldiers.
Thanks ThoughtBubble.
Tragically, Marie died in 1934 of cancer.
She literally gave her life to help others.
And belatedly, in 1995, Marie Skłodowska
Curie—the first female professor at the
Sorbonne—became the first woman to be entombed
in Paris’s Panthéon, AKA Science Valhalla,
for her own achievements.
But Marie was not the only professional woman
scientist to succeed in the early 1900s.
Other notables include American chemist Alice
Ball, one of the first female chemistry professors
and one of the first professional African-American
women of science.
She developed the best treatment for Hansen’s
disease, or leprosy, until World War II.
Czech–American biochemist Gerty Cori worked
out the important cycle of how glycogen, a
form of sugar, breaks down in muscles into
lactic acid, and then is reformed as a source
of energy.
This became known as the Cori cycle, and she
won the Nobel Prize for discovering it in
1947.
Finally, the Curies’ daughter, Irène Joliot-Curie,
was an outstanding chemist who also won a
Nobel!
While Nobels aren’t the only or best way
to tell the story of the history of science,
the fact that we could do whole episodes on
three different members of the Curie family
is just.
Dang.
Impressive.
Next time—we follow the development of modern
physics into the office of a humble patent
clerk with a big secret: the key to the relationship
between matter and energy.
It’s Einstein o’clock!
Crash Course History of Science is filmed
in the Dr. Cheryl C. Kinney studio in Missoula,
Montana and it’s made with the help of all
this nice people and our animation team is
Thought Cafe.
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