- On November 8th of 1895, a shy and diligent scientist
named Wilhelm Roentgen noticed a flicker
on a fluorescent screen and changed our world
with his discovery of what he called,
and we still call, X-rays.
But who was Roentgen?
Why did he discover X-rays,
and how did a dirty picture almost derail his life?
Ready for the story? Let's go.
♪ Electricity, electricity. ♪
Wilhelm Roentgen was the only child
of a middle-class merchant and his wife, and was expected
to be a merchant too, but he was more interested
in academics and nature.
However, his career was almost cut short at age 16,
when a friend drew a caricature of a teacher
and Roentgen refused to name the culprit.
Unfairly blamed for it,
Roentgen was expelled from school.
It must've been a really bad drawing.
Anyway, he tried to go to university
but his reputation kept him away.
And he ended up at Zurich Technical Polytechnic,
which was one of the few colleges in Europe that accepted
people who had a non-traditional path to college.
Albert Einstein and his first wife, Mileva Maric,
went there 45 years later for the same reason.
It was at Zurich Polytechnic that Roentgen's friend
introduced him to Professor August Kundt.
Years later, Roentgen recalled, quote,
"Kundt introduced me to physics and thus removed
the doubt and uncertainty regarding my future."
In 1869, Roentgen got his PhD under Kundt
and then became his assistant.
Roentgen was such a careful and productive experimentalist
that he was soon courted as a teacher by the very schools
that rejected him as a student years earlier.
Roentgen was a quiet man who did not like loud parties
and preferred to talk with friends at the local cafe.
It was at such a cafe that Roentgen met
the cafe owner's daughter, Anna Bertha Ludwig.
When when Roentgen was 26 and Bertha 31, they married,
and remained happily married for the next 50 years.
It was around this time that Roentgen grew
a great bushy beard that became part of his look
for the rest of his life.
They never had any biological children, but 15 years later
they adopted Bertha's niece, Josephine Bertha Ludwig,
confusingly called Little Bertha, who they doted on.
His other great love was experimenting.
He said, quote, "the intellectual life gives us the purest
and highest joy of which the human being is capable.
For the next 20 years, Roentgen happily researched
and was well-regarded by a select group of German scientists
and virtually unknown elsewhere.
That started to change in 1892.
That's when Roentgen's friend Heinrich Hertz published
his work on the cathode ray, which is an invisible ray
that emanates from a negative electrode in a vacuum tube
and can make phosphors and glass glow.
Hertz found that these rays could travel
through thin pieces of aluminum or gold foil.
In 1894, Hertz' assistant, Philip Lenard, made a window
out of aluminum so that the cathode rays would escape
the tube and travel for one or two inches in air.
Now none of these people knew it, but the cathode ray
was a beam of fast-moving electrons
and bombarding a solid with fast moving electrons
produces X-rays.
Lenard covered his tube with thick cardboard
that blocked everything but the X-rays from exiting
the side of the tube and used phosphors to detect
the cathode rays outside the window.
Unfortunately for Lenard, he used a phosphor plate
composed of low-mass elements that were basically
transparent to X-rays, or he would have
discovered the X-ray first.
Roentgen recalled that he had been, quote,
"for a long time interested in the problems
of the cathode rays from vacuum tubes",
the study by Hertz and Lenard.
In October of 1895 Roentgen began to hand-build
different types of vacuum tubes.
A month later Roentgen was working late
after his assistants had gone home
and noticed the phosphor plate glowing
to the side of a covered excited tube.
We have no proof of which of his many vacuum tubes
Roentgen was using that fateful night.
However, it really only makes sense to do this experiment
with a Lenard tube, as this was the only one you covered
and studied from the outside.
Roentgen realized that something was coming from the tube
and traveling long distance, but the cardboard
blocked out all visible and ultraviolet light,
and the cathode rays only went a few inches
out of the window.
What was happening?
Roentgen recalled, quote,
"it seemed at first a new kind of invisible light."
It was clearly something new, something unrecorded.
He told his wife he was working on something
that would probably make people say,
"Roentgen has surely gone crazy,"
but what was this invisible light?
Why did he name it X-rays, and how did he accidentally
figure out how to take medical X-ray pictures?
That is next time on "The Lightning Tamers."
♪ Electricity, electricity. ♪
Thanks for watching my video,
please remember to give a thumbs up.
Also, if you're interested in more about Hertz
and Lenard and their X-ray machines that they didn't know
were X-ray machines, please check out my last video.
Okay. Have a nice day.
(jazzy music continues)