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  • 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 Prizeswhich started being given out in Marie's timearen'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 universein which

  • large, visible stuff collides due to the invisible but lawlike action of gravityas well as

  • the strange world of thermodynamics and electromagnetism.

  • Heat is energy!

  • Radio waves can carry signals around the world!

  • All weirdand about to get weirder.

  • In 1895, German engineer Wilhelmntgen

  • 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 glowingand yet, my dude's cardboard glowed.

  • Sontgen 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.

  • Sontgen threw himself into investigating what he calledspooky raysafter 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 Berthantgen let her husband make an image of the bones in her hand using X-rays.

  • And thenntgen 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 radiologyor 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 tontgen's X-rays.

  • So he busted out his inherited supply of his father's uraniumyes! 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 decayradioactivity.”

  • 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 thatntgen 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.

  • Bornto 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 physicsbasically 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?

  • Butplot twistPierre 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 washis 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 aboutntgen'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

  • matterthe atomthat 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 sayshe,” 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 famouslyshe 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 Curiethe first female professor at the

  • Sorbonnebecame 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.

  • CzechAmerican 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 timewe 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.

  • Crash Course is a Complexly production.

  • If you wanna keep imagining the world complexly with us, you can check out some of our other

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  • Thank you to all of our patrons for making Crash Course possible with their continued

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The late 1800s and early 1900s saw a revolution in the very basics of what-is-stuff.

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