TED-Ed
Adam Savage: How simple ideas lead to scientific discoveries
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Adam Savage walks through two spectacular examples of profound scientific discoveries that came from simple, creative methods anyone could have followed -- Eratosthenes' calculation of the Earth's circumference around 200 BC and Hippolyte Fizeau's measurement of the speed of light in 1849.
Adam Savage - Maker, critical thinker
Adam Savage is an internationally renowned television producer, host and public speaker. Full bio
Adam Savage is an internationally renowned television producer, host and public speaker. Full bio
Double-click the English transcript below to play the video.
00:14
One of the funny things
about owning a brain
about owning a brain
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is that you have
no control over the things
no control over the things
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that it gathers and holds onto,
the facts and the stories.
the facts and the stories.
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And as you get older, it only gets worse.
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Things stick around for years sometimes
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before you understand
why you're interested in them,
why you're interested in them,
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before you understand their import to you.
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Here's three of mine.
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When Richard Feynman
was a young boy in Queens,
was a young boy in Queens,
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he went for a walk with his dad
and his wagon and a ball.
and his wagon and a ball.
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He noticed that when he pulled the wagon,
the ball went to the back of the wagon.
the ball went to the back of the wagon.
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He asked his dad, "Why does
the ball go to the back of the wagon?"
the ball go to the back of the wagon?"
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And his dad said, "That's inertia."
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He said, "What's inertia?"
And his dad said, "Ah.
And his dad said, "Ah.
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Inertia is the name that scientists give
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to the phenomenon of the ball
going to the back of the wagon."
going to the back of the wagon."
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(Laughter)
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"But in truth, nobody really knows."
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01:00
Feynman went on to earn degrees
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at MIT, Princeton, he solved
the Challenger disaster,
the Challenger disaster,
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he ended up winning
the Nobel Prize in Physics
the Nobel Prize in Physics
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for his Feynman diagrams, describing
the movement of subatomic particles.
the movement of subatomic particles.
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And he credits that conversation
with his father as giving him a sense
with his father as giving him a sense
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that the simplest questions could carry
you out to the edge of human knowledge,
you out to the edge of human knowledge,
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and that that's where he wanted to play.
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And play he did.
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Eratosthenes was the third librarian
at the great Library of Alexandria,
at the great Library of Alexandria,
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and he made many contributions to science.
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But the one he is most remembered for
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began in a letter that he received
as the librarian,
as the librarian,
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from the town of Swenet,
which was south of Alexandria.
which was south of Alexandria.
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The letter included this fact
that stuck in Eratosthenes' mind,
that stuck in Eratosthenes' mind,
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and the fact was that the writer said,
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at noon on the solstice,
when he looked down this deep well,
when he looked down this deep well,
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he could see his reflection at the bottom,
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and he could also see
that his head was blocking the sun.
that his head was blocking the sun.
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I should tell you -- the idea
that Christopher Columbus
that Christopher Columbus
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discovered that the world
is spherical is total bull.
is spherical is total bull.
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It's not true at all.
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In fact, everyone who was educated
understood that the world was spherical
understood that the world was spherical
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since Aristotle's time.
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Aristotle had proved it
with a simple observation.
with a simple observation.
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He noticed that every time you saw
the Earth's shadow on the Moon,
the Earth's shadow on the Moon,
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it was circular,
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and the only shape that constantly
creates a circular shadow
creates a circular shadow
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is a sphere, Q.E.D. the Earth is round.
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But nobody knew how big it was
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until Eratosthenes got
this letter with this fact.
this letter with this fact.
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So he understood that the sun
was directly above the city of Swenet,
was directly above the city of Swenet,
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because looking down a well,
it was a straight line
it was a straight line
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all the way down the well,
right past the guy's head up to the sun.
right past the guy's head up to the sun.
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Eratosthenes knew another fact.
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He knew that a stick stuck
in the ground in Alexandria
in the ground in Alexandria
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at the same time
and the same day, at noon,
and the same day, at noon,
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the sun's zenith, on the solstice,
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the sun cast a shadow that showed
that it was 7.2 degrees off-axis.
that it was 7.2 degrees off-axis.
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If you know the circumference of a circle,
and you have two points on it,
and you have two points on it,
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all you need to know is the distance
between those two points,
between those two points,
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and you can extrapolate the circumference.
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360 degrees divided by 7.2 equals 50.
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I know it's a little bit
of a round number,
of a round number,
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and it makes me suspicious
of this story too,
of this story too,
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but it's a good story,
so we'll continue with it.
so we'll continue with it.
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He needed to know the distance
between Swenet and Alexandria,
between Swenet and Alexandria,
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which is good because Eratosthenes
was good at geography.
was good at geography.
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In fact, he invented the word geography.
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(Laughter)
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The road between Swenet and Alexandria
was a road of commerce,
was a road of commerce,
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and commerce needed to know
how long it took to get there.
how long it took to get there.
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It needed to know the exact distance,
so he knew very precisely
so he knew very precisely
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that the distance between
the two cities was 500 miles.
the two cities was 500 miles.
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Multiply that times 50, you get 25,000,
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which is within one percent
of the actual diameter of the Earth.
of the actual diameter of the Earth.
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He did this 2,200 years ago.
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Now, we live in an age where
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multi-billion-dollar pieces of machinery
are looking for the Higgs boson.
are looking for the Higgs boson.
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We're discovering particles
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that may travel faster
than the speed of light,
than the speed of light,
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and all of these discoveries
are made possible
are made possible
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by technology that's been developed
in the last few decades.
in the last few decades.
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But for most of human history,
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we had to discover these things using
our eyes and our ears and our minds.
our eyes and our ears and our minds.
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Armand Fizeau was
an experimental physicist in Paris.
an experimental physicist in Paris.
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His specialty was actually refining
and confirming other people's results,
and confirming other people's results,
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and this might sound
like a bit of an also-ran,
like a bit of an also-ran,
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but in fact, this is the soul of science,
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because there is no such thing as a fact
that cannot be independently corroborated.
that cannot be independently corroborated.
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And he was familiar
with Galileo's experiments
with Galileo's experiments
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in trying to determine
whether or not light had a speed.
whether or not light had a speed.
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Galileo had worked out this
really wonderful experiment
really wonderful experiment
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where he and his assistant had a lamp,
each one of them was holding a lamp.
each one of them was holding a lamp.
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Galileo would open his lamp,
and his assistant would open his.
and his assistant would open his.
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They got the timing down really good.
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They just knew their timing.
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And then they stood at two hilltops,
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two miles distant,
and they did the same thing,
and they did the same thing,
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on the assumption from Galileo
that if light had a discernible speed,
that if light had a discernible speed,
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he'd notice a delay in the light
coming back from his assistant's lamp.
coming back from his assistant's lamp.
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But light was too fast for Galileo.
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He was off by several orders
of magnitude when he assumed
of magnitude when he assumed
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that light was roughly ten times
as fast as the speed of sound.
as fast as the speed of sound.
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Fizeau was aware of this experiment.
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He lived in Paris, and he set up
two experimental stations,
two experimental stations,
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roughly 5.5 miles distant, in Paris.
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And he solved this problem of Galileo's,
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and he did it with a really relatively
trivial piece of equipment.
trivial piece of equipment.
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He did it with one of these.
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I'm going to put away
the clicker for a second
the clicker for a second
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because I want to engage
your brains in this.
your brains in this.
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So this is a toothed wheel.
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It's got a bunch of notches
and it's got a bunch of teeth.
and it's got a bunch of teeth.
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This was Fizeau's solution
to sending discrete pulses of light.
to sending discrete pulses of light.
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He put a beam behind one of these notches.
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If I point a beam
through this notch at a mirror,
through this notch at a mirror,
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five miles away, that beam
is bouncing off the mirror
is bouncing off the mirror
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and coming back to me through this notch.
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But something interesting happens
as he spins the wheel faster.
as he spins the wheel faster.
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He notices that it seems
like a door is starting to close
like a door is starting to close
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on the light beam
that's coming back to his eye.
that's coming back to his eye.
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Why is that?
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It's because the pulse
of light is not coming back
of light is not coming back
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through the same notch.
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It's actually hitting a tooth.
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And he spins the wheel fast enough
and he fully occludes the light.
and he fully occludes the light.
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And then, based on the distance
between the two stations
between the two stations
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and the speed of his wheel
and the number of notches in the wheel,
and the number of notches in the wheel,
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he calculates the speed of light
to within two percent of its actual value.
to within two percent of its actual value.
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And he does this in 1849.
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This is what really gets me
going about science.
going about science.
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Whenever I'm having trouble
understanding a concept,
understanding a concept,
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I go back and I research
the people that discovered that concept.
the people that discovered that concept.
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I look at the story of how
they came to understand it.
they came to understand it.
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What happens when you look
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at what the discoverers
were thinking about
were thinking about
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when they made their discoveries,
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is you understand that
they are not so different from us.
they are not so different from us.
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We are all bags of meat and water.
We all start with the same tools.
We all start with the same tools.
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I love the idea that different branches
of science are called fields of study.
of science are called fields of study.
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Most people think of science
as a closed, black box,
as a closed, black box,
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when in fact it is an open field.
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And we are all explorers.
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The people that made these discoveries
just thought a little bit harder
just thought a little bit harder
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about what they were looking at,
and they were a little bit more curious.
and they were a little bit more curious.
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And their curiosity changed the way
people thought about the world,
people thought about the world,
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and thus it changed the world.
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They changed the world, and so can you.
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Thank you.
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(Applause)
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Translated by Jenny Zurawell
ABOUT THE SPEAKER
Adam Savage - Maker, critical thinkerAdam Savage is an internationally renowned television producer, host and public speaker.
Why you should listen
Adam Savage's mother is a psychologist; his father was a celebrated artist, painter and filmmaker. From the youngest age they encouraged his flights of fancy. Savage has been a paperboy, a projectionist, juggler, unicycle rider, sculptor, graphic designer, scenic painter, robot builder, welder, carpenter, machinist, prop maker, toy designer, actor, writer, executive producer and director. He spent six years in theater and 10 years in commercial and film special effects working for clients such as Nike, Corning, Hershey's, and Coca-Cola, and films like Star Wars, The Matrix films, A.I., Space Cowboys, Terminator 3 and Galaxy Quest.
Savage has built everything from theater sets to miniature particle accelerators. From spaceships to animatronic arms. He's made Rube Goldberg machines, hand props and spacesuits. His online videos have generated over 230 million page views. He's written for Popular Mechanics, the Wall Street Journal and Wired Magazine, among others. His program "Mythbusters" produced 270 episodes that aired in over 100 countries for 14 years. Adam shares his builds, his love for movie props and costumes, and passion for the transformative power of making on his award winning website Tested.com. He lives in San Francisco with his wife Julia, his twin boys Thing1 and Thing2, and two amazing dogs.
(Photo: Michael Shindler)
Adam Savage | Speaker | TED.com