Like thermodynamics, the history of electrical
physics has its roots in pre-industrial questions
that converged in the nineteenth century.
These questions became a research paradigm,
driven by a whole crew of researchers… And
they led to a power system that reshaped the
world. Time to get tingly!
[Intro Music Plays]
The study of electricity goes all the way
back to antiquity. Like, for a long time,
people knew that lightning is the powerful
release of energy caused when two clouds are
in love and make a baby cloud.
But that's hard to study.
Much easier to study, however, was static
electricity, or the electrical charge produced
by stationary friction: it waits for you to
pet your cat, and then shocks you!
But for centuries, natural historians didn’t
really have any good ideas about how to more
deeply understand this phenomenon.
For one, they had no concept of current, or
electricity as a flow of electrical charge.
Current can happen either by the movement
of negatively charged subatomic particles
called electrons through wires, or by the
movement of charged molecules called ions.
And these people didn't know either of those things existed.
Secondly, the relationship between electricity
and magnetism, which are intimately linked,
was a mystery.
And, third, a lot of experimentation into
these phenomenon basically amounted to weird
parlor tricks that had no obvious uses.
English natural philosopher Francis Hauksbee,
for example, found out in the early 1700s
that spinning a glass globe produced electricity—thus
creating one of the first electrical generators.
Then, in 1729, two amateur scholars named
Stephen Gray and Granville Wheler discovered
that electricity could be communicated over
long distances by contact.
This was an important first step toward researching
currents. But mostly it was an excuse to conduct
totally ethical scientific demonstrations…
like suspending a young boy from the ceiling,
charging him up, and then watching him attract
objects with different body parts.
And we can’t forget statesman, encyclopedist,
and infamous knowitall Ben Franklin.
He witnessed one of these flying-boy demonstrations
in Boston, then went home to Philadelphia
and waited for a thunderstorm.
As the story goes, in 1752, he flew his kite
in a storm and succeeded in “drawing off”
electrical fire.
Inspired by this incident, he developed the
lightning rod. But no real epistemic knowledge.
One of the first modern electrical physicists
was Italian physician Luigi Galvani.
In the late 1700s, his assistant accidentally
caused a frog’s leg to twitch with a spark
from a nearby electrostatic generator.
Inspired by this chance observation, he conducted
many freaky experiments with frogs.
After much frog-shocking, he theorized the
existence of animal electricity, or the electrical
basis of nerve impulses.
That inspired one young woman who was remarkably
well informed about contemporary science:
in 1818, Mary Shelley published what would
become a very famous book about a man zapped
to life by a Galvani-esque Doctor Frankenstein.
Galvani also inspired his colleague, Italian
physicist and chemist Alessandro Volta, to
push his work on nerves further.
And Volta became a rockstar of electrical
physics when he created the first practical
method of generating electricity—the first
battery, known as the voltaic pile
So ThoughtBubble, let's make some sparks fly!
Volta’s battery evolved from humble origins.
The first iterations were made of two different
metals separated by a brine-soaked cloth or
piece of cardboard.
But Volta kept improving the pile. In 1800,
he stacked pairs of copper and zinc discs,
again separated by briny cloth or cardboard.
When he connected the top and bottom of the
pile, it generated a steady electric current
that could be carried by a wire.
Volta had created the first stable source of electrical
current!
This type of two-metal battery fulfilled the
world’s scant electrical needs throughout
much of the First Industrial Revolution, until
around 1870.
But no one could really explain how it worked,
in part because no one had brought electricity
and magnetism together.
One of the first steps in this direction was
taken in 1820 by Danish physicist and chemist
Hans Christian Ørsted.
While demonstrating to his students how to
heat up a wire by running an electrical current
through it, Ørsted noticed that his compass’
needle kept jumping to a ninety-degree angle.
Somehow, he realized, the electrical charge
and the magnetic attraction of the compass
were linked.
Ørsted conducted further experiments and
showed that electric currents actually produce
neatly circular magnetic fields when they
flow through wires.
This became known as Ørsted’s law.
Later in 1820, at the Academy of Science
in Paris, physicist André-Marie Ampère watched
as a friend reproduced Ørsted’s electrically-messing-with-a-compass
trick.
Amazed, Ampère went to work figuring out
the math behind this special relationship.
He showed that two parallel, electrified wires
attract each other if the currents flow in
the same direction, and repel if the currents
flow in opposite directions.
Thanks Thoughtbubble. Ampère also showed
that the force between the currents was inversely
proportional to the distance between them,
and proportional to the intensity of the current
flowing in each.
This became known as Ampère's law. You can
watch a whole episode about that over at Crash
Course: Physics!
And he even theorized that there must be some
“electrodynamic molecule” that carried
the currents of electricity and magnetism.
This became the basis for the electron.
Ampère’s insights became the foundation
of the quantitative science of electromagnetism,
or “electrodynamics.”
In 1827, Germany physicist Georg Ohm —who’d
been conducting research using Volta’s battery—published
his discovery that an electrical current
between two points is directly proportional
to the voltage, or potential difference, between
them.
This became known as Ohm’s law.
This can be expressed using the concept of
resistance, or the difficulty of passing an
electric current through that conductor, in
a really simple equation:
“I = V/R.” Current, measured in amperes,
is equal to voltage, measured in volts, divided
by resistance, measured in ohms.
Yep: all three scientists became standard
units.
Congrats, scientists!
They say, in Physics the greatest honor is when your name starts to be spelled with a lower case letter.
With practical batteries and basic scientific
laws, the stage was set for electricity to
become an industry—enter motors and lights.
Born to a poor family in Newington Butts,
London, Michael Faraday became obsessed with
electricity and chemistry at a young age.
Eventually, he became as important to the
sciences of stuff as Darwin was to those of
life.
In 1821—a year after Ørsted characterized
electromagnetism and Ampère began experimenting
with the math behind it—Faraday got to work
inventing electromagnetic motors.
His motors worked due to “electromagnetic
rotation,” a motion made by the circular
magnetic force around an electrified wire.
In 1831, he had his big breakthrough—electromagnetic
induction, meaning the generation of electricity
in one wire via the changing magnetic field
created by the current in another wire.
This became the basis of the electromagnetic
technologies that we use today.
So… thanks, Mike!
In the same year, Faraday also discovered
magneto-electric induction, which is the generation
of a steady, direct electrical current in
a wire by attaching it to a copper disc,
and then rotating the disc between the poles
of a magnet. This was the first modern electrical
generator!
And he proved that the electricity created
by magnetic induction, the electricity produced
by a voltaic battery, and good ole static
electricity were all the same phenomenon.
Faraday’s experiments led to the invention
of modern electrical motors, generators, and
transformers.
He figured out how to make electricity do
work on magnetism and vice versa.
And his young buddy, Scottish physicist James
Clerk Maxwell, played the Ampère to his Volta,
figuring out the math involved in induction.
In 1855, Maxwell dropped “On Faraday’s
lines of force,” showing Faraday’s discoveries
about electricity and magnetism in the forms
of differential equations.
Maxwell’s long paper, “On Physical Lines
of Force,” introduced his full theory of
electromagnetism in parts over 1861 and ‘62.
Here, he theorized that electromagnetic waves
travel at the speed of light, and that light
must exist in the same medium as electrical
and magnetic energy.
By connecting light, electricity, and magnetism,
Maxwell laid the groundwork for modern physics.
And his work was a major influence on Einstein.
But the average person in the 1870s didn’t
know who Faraday and Maxwell were, much less
that they had revolutionized energy and work.
There was still no system for using electricity
industrially.
For that useful system, we have to hop across
the Atlantic to the first home of corporate
research and development in science—Menlo
Park, New Jersey.
Here, a mix of brilliant engineers, scarcely
trained boys, and one pet bear (yes!) worked
under the direction of a controversial inventor—
who was or was decidedly not much of a scientist
himself, depending on which historian you
prefer.
His name was Thomas Edison.
Edison, or the “Wizard of Menlo Park,”
or the “Napoleon of Science,” started
his career as a lowly telegraph operator at
the age of sixteen.
He worked his way up, improving telegraph
systems, until he could open his own contract-based-lab-slash-workshop
in 1876.
Mostly, people remember Edison for his work
on making practical incandescent light bulbs,
but he should really be thought of as the
person who first saw the potential for an
entire electrical grid.
This included the generation of power, its
distribution to homes and businesses, and
the invention of useful products that required
electricity to work.
In the late 1870s, people didn’t understand
or see the need for electricity. Customers
had to be created. So what did Edison do?
Befriended the richest guy in New York, who
was also the richest guy in the world—J.
P. Morgan.
With Morgan’s money, Edison had the resources
to work out the longest-lasting filament,
or slender, heated-up-until-visibly-lighted
bit, for his bulbs.
This ended up being made of carbon, after
thousands of experiments on different materials.
But he also had the resources to show off
his lights in Paris and London. And, most
importantly, to electrify downtown Manhattan.
Think about it for a second: the night before
1880 was dark.
Yes, gas lamps existed, but they were weak,
smelly, and dangerous.
Edison’s electrification of the cultural
and financial capital of an ascendent American
empire was… blindingly amazing.
People stayed up longer. More work got done.
The feedback loop of just pushing off bedtime
by a few hours was enormous—and this was
before anyone had devised a good mass-scale
electrical motor or vehicle.
It’s true that Edison didn’t invent the
components of his electrical power system,
only improved upon them,
thanks to his team-based, finance-backed approach
to science and technology.
And it’s true that he became embroiled in
an intense public battle called the Current War,
over the safety and efficiency of his direct
current, or DC, versus his rival Westinghouse’s
much more practical alternating current, or
AC.
Aaaaand it’s true that Edison promoted capital
punishment in New York, using an electric
chair powered by Westinghouse’s AC.
But—beginning with incandescent light—Edison
and other inventors used the discoveries of
the early electrical physicists to utterly
transform the world.
Next time—we’ll follow Edison, tracing
the effects of corporate research and mega-scale
engineering through many fields during the
Second Industrial Revolution. It’s time
to go big or go bigger!
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
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