Shock and Awe: The Story of Electricity -- Jim Al-Khalili BBC Horizon

Part 1 - Spark 0:00
Part 2 - The Age of Invention 58:30
Part 3 - Revelations and Revolutions 1:56:50

---------

In this three-part BBC Horizon documentary physicist and science communicator Jim Al-Khalili takes the viewer on a journey exploring the most important historical developments in electricity and magnetism. This documentary discusses how the physics (and the people behind the physics) changed the world forever.

---------

BBC Horizon 2011

At the dawn of the 19th century,

in a cellar in Mayfair,

the most famous scientist
of the time, Humphry Davy,

built an extraordinary piece
of electrical equipment.

Four metres wide, twice as long

and containing stinking stacks
of acid and metal,

it had been created to pump out
more electricity

than had ever been possible before.

It was in fact the biggest battery

the world had ever seen.

With it, Davy was about to propel us

into a new age.

That moment would take place at
a lecture at the Royal Institution,

in front of hundreds
of London's great and good.

Filled with anticipation,
they packed the seats,

hoping to witness a new
and exciting electrical wonder.

But what they would see that night
would be something truly unique.

Something they would remember
for the rest of their lives.

Using just two simple carbon rods,

Humphry Davy was about to unleash
the true potential of electricity.

Electricity is one of nature's
most awesome phenomena,

and the most powerful manifestation
of it we ever see

is lightning.

This is the story of how
we first dreamed of controlling

this primal force of nature,

and how we would ultimately
become its master.

It's a 300-year tale

of dazzling leaps of imagination
and extraordinary experiments.

Tens of thousands of volts
passed across his body

and through the end of a lamp
that he was holding.

It's a story of a maverick geniuses

who used electricity
to light our cities,

to communicate across the seas
and through the air,

to create modern industry and
to give us the digital revolution.

But in this film, we'll tell the
story of the very first scientists

who started to unlock
the mysteries of electricity.

It's as though
there's something alive in there.

They studied
its curious link to life,

built strange and powerful
instruments to create it

and even tamed lightning itself.

It was these men who truly laid
the foundations of the modern world.

And it all started with a spark.

Imagine our world
without electricity.

It would be dark,

cold and quiet.

In many ways, it would be like
the beginning of the 18th century,

where our story begins.

This is the Royal Society in London.

In the early 1700s,
after years in the wilderness,

Isaac Newton
finally took control of it

after the death of his arch-enemy,
Robert Hooke.

Newton brought in his own people
to the key jobs,

to help shore up his new position.

The new head of demonstrations there
was 35-year-old Francis Hauksbee.

Notes from the Royal Society in 1705

reveal how hard Hauksbee tried

to stamp his personality
on its weekly meetings,

producing ever more spectacular
experiments to impress his masters.

In November, he came up with this -

a rotating glass sphere.

He was able to remove the air
from inside it using a new machine -

the air pump.

On his machine, a handle allowed him
to spin the sphere.

One by one,
the candles in the room were put out

and Francis placed his hand
against the sphere.

The audience were about to see
something amazing.

'Inside the glass sphere,

'a strange ethereal light
began to form,

'dancing around his hand.

'A light
no-one had ever seen before.'

That's fantastic.

You see a beautiful blue glow,
it's just marking out

the shape of my hands,
but then going right round the ball.

It's as though
there's something alive in there.

It's difficult to really understand

why this dancing blue light
meant so much,

but we have to bear in mind
that at the time,

natural phenomena like this were
seen to be the work of the Almighty.

This was still a period when,
even in Isaac Newton's theory,

God was constantly intervening
in the conduct of the world.

It made sense for a lot of people

to interpret natural phenomena
as acts of God.

So when a mere mortal
meddled with God's work,

it was almost beyond
rational comprehension.

Hauksbee never realised the full
significance of his experiment.

He lost interest
in his glowing sphere

and spent the last few years
of his life

building ever more
spectacular experiments

for Isaac Newton
to test his other theories.

He never realised
that he had unwittingly started

an electrical revolution.

Before Hauksbee, electricity
had been merely a curiosity.

The ancient Greeks rubbed amber,
which they called electron,

to get small shocks.

Even Queen Elizabeth I marvelled

at static electricity's power
to lift feathers.

But now Hauksbee's machine

could make electricity
at the turn of a handle,

and you could see it.

Perhaps even more importantly,
his invention coincided

with the birth of a new movement
sweeping across Europe

called the Enlightenment.

Enlightened intellectuals
used reason to question the world

and their legacy
was radical politics,

iconoclastic art

and natural philosophy, or science.

But ironically,
Hauksbee's new machine

wasn't immediately embraced
by most of these intellectuals.

But instead,
by conjurers and street magicians.

Those with an interest
in electricity

called themselves electricians.

One story tells of a dinner party
attended by an Austrian Count.

The electrician had placed
some feathers on the table

and then charged up a glass rod
with a silk handkerchief.

He then astonished the guests
by lifting up the feathers

with the rod.

He then went on to charge himself up

using one of Hauksbee's
electrical machines.

He gave the guests electric shocks,
presumably to squeals of delight.

But for his piece de resistance,

he placed a glass of cognac
in the centre of the table,

charged himself up again

and lit it with a spark
from the tip of his finger.

There was a trick called
the electrical beatification,

in which the victim sits
on an insulated chair

and above his head
hangs a metal crown

that doesn't quite touch his head.

And then if the crown
is electrified,

then you get an electric discharge
around the crown

that looks exactly like a halo,

which is why it's called
the electric beatification.

As England and the rest of Europe
went electricity crazy,

the spectacles grew bigger.

The more curious electricians

started to ask
more profound questions,

not only how can we make
our shows bigger and better,

but how can we control
this amazing power?

And for some, can this incredible
electrical fire

do more than just entertain?

One of the first early breakthroughs
would never have happened

had it not been
for a terrible accident.

This is Charterhouse
in the centre of London.

Over the past 400 years,
it's been a charitable home

for young orphans
and elderly gentleman.

And sometime in the 1720s, it also
became home to one Stephen Gray.

Stephen Gray had been a successful
silk dyer from Canterbury.

He was used to seeing
electric sparks leap from the silk

and they fascinated him.

Unfortunately, a crippling accident
ended his career

and left him destitute.

But then he was offered
a new life here at Charterhouse

and with it the time to perform
his own electrical experiments.

Here at Charterhouse, possibly in
this very room, the Great Chamber,

Stephen Gray built a wooden frame

and from the top beam he suspended
two swings using silk rope.

He also had a device like this,
a Hauksbee machine

for generating static electricity.

Now, with a large audience
in attendance,

he got one of the orphan boys
who lived here at Charterhouse

to lie across the two swings.

Gray placed some gold leaf
in front of him.

He then generated electricity

and charged the boy
through a connecting rod.

Gold leaf, even feathers,
leapt to the boy's fingers.

Some of the audience
claimed they could even see sparks

flying out from his fingertips.
Show business indeed.

But to the curious
and inquiring mind of Stephen Gray,

this said something else as well -

electricity could move,

from the machine to the boy's body,
through to his hands.

But the silk rope stopped it dead.

It meant the mysterious
electrical fluid

could flow through some things...

..but not through others.

It led Gray to divide the world into
two different kinds of substances.

He called them
insulators and conductors.

Insulators held
electric charge within them

and wouldn't let it move,
like the silk or hair,

glass and resin.

Whereas conductors allowed
electricity to flow through them,

like the boy or metals.

It's a distinction
which is still crucial even today.

Just think of these electric pylons.

They work on the same principle
that Gray deduced

nearly 300 years ago.

The wires are conductors.

The glass and ceramic objects

between the wire and the metal
of the pylon are insulators

that stop the electricity
leaking from the wires

into the pylon
and down to the earth.

They're just like the silk ropes
in Gray's experiment.

Back in the 1730s,

Gray's experiment
may have astounded all who saw it,

but it had a frustrating drawback.

Try as he might, Gray
couldn't contain the electricity
he was generating for long.

It leapt from the machine
to the boy and was quickly gone.

The next step in our story came

when we learnt
how to store electricity.

But that would take place
not in Britain,

but across the Channel
in mainland Europe.

Across the Channel,
electricians were just as busy

as their British counterparts and
one centre for electrical research

was here in Leiden, Holland.

And it was here that a professor
came up with an invention

that many still regard as the most
significant of the 18th century,

one that in some form or another
can still be found

in almost every
electrical device today.

That professor
was Pieter van Musschenbroek.

Unlike Hauksbee and Gray,

Musschenbroek
was born into academia.

But ironically enough,
his breakthrough

came not because
of his rigorous science,

but because
of a simple human mistake.

He was trying to find a way
to store electrical charge,

ready for his demonstrations.
And you can almost hear

his train of thought
as he tries to figure this out.

If electricity is a fluid
that flows, a bit like water,

then maybe you can store it in the
same way that you can store water.

So Musschenbroek
went to his laboratory

to try to make a device
to store electricity.

Musschenbroek started
to think literally.

He took a glass jar
and poured in some water.

He then placed inside it
a length of conducting wire...

..which was connected at the top
to a Hauksbee electric machine.

'Then he put the jar on an insulator
to help keep the charge in the jar.'

He then tried to pour
the electricity into the jar

produced by the machine via the wire

down through into the water.

'But whatever he tried, the charge
just wouldn't stay in the jar.

'Then one day, by accident,

'he forgot to put the jar
on the insulator,

'but charged it instead
while it was still in his hand.'

Finally, holding the jar
with one hand,

he touched the top with the other

and received
such a powerful electric shock,

he was almost thrown to the ground.

He writes, "It's a new
but terrible experiment

"which I advise you never to try.
Nor would I, who've experienced it

"and survived by the grace of God
do it again

"for all the kingdom of France."

So I'm going to heed his advice,
not touch the top,

and instead see if I can get
a spark off of it.

The sheer power of the electricity
which flew from the jar

was greater than any seen before.

And even more surprisingly,

the jar could store that electricity
for hours, even days.

So in honour of the city where
Musschenbroek made his discovery,

they called it the Leiden jar.

And its fame
swept across the world.

And very rapidly, from 1745
through the rest of the 1740s,

the news of this - it's called
the Leiden jar - goes global.

It spreads from Japan in East Asia

to Philadelphia in eastern America.

It became one of the first quick,
globalised, scientific news items.

But although the Leiden jar became
a global electrical phenomenon,

no-one had the slightest
idea how it worked.

You have a jar of electric fluid,

and it turns out that you get
a bigger shock from the jar

if you allow the electric fluid
to drain away to the earth.

Why is the shock bigger
if the jar's leaking?

Why isn't the shock bigger if you
make sure all the electric fluid

stays inside the jar?

That was how mid-18th century
electrical philosophers

were faced with this challenge.

Electricity was without doubt
a fantastical wonder.

It could shock and spark.

It could now be stored
and moved around.

Yet what electricity was,
how it worked,

and why it did all these things

was nothing less
than a complete mystery.

Within 10 years,
a new breakthrough was to come

from an unexpected quarter,

From a man politically
and philosophically at war

with the London establishment.

And even more shockingly
for the British electrical elite,

that man was merely a colonial.

An American.

This painting of Benjamin Franklin

hangs here at the
Royal Society in London.

Franklin was a passionate supporter
of American emancipation

and saw the pursuit
of rational science,

and particularly electricity,

as a way of rolling back ignorance,
false idols

and ultimately his intellectually
elitist colonial masters.

And this is mixed with a profoundly
egalitarian democratic idea

that Franklin and his allies have,

which is this is
a phenomenon open to everyone.

Here's something that the elite
doesn't really understand

and we might be able
to understand it.

Here's something that the elite
can't really control

but we might be able to control.

And here's something above all which
is the source of superstition.

And we, rational, egalitarian,

potentially democratic,
intellectuals,

we will be able to reason it out,

without appearing to be
the slaves of magic or mystery.

So Franklin decided to use
the power of reason

to rationally explain what many

considered a magical phenomenon...

Lightning.

THUNDER BOOMS

This is probably one of the most
famous scientific images

of the 18th century.

It shows Benjamin Franklin,
the heroic scientist,

flying a kite in a storm,

proving that lightning
is electrical.

But although Franklin
proposed this experiment,

he almost certainly
never performed it.

Much more likely is that
his most significant experiment

was another one which he proposed
but didn't even conduct.

In fact, it didn't
even happen in America.

It took place here in a small
village north of Paris

called Marly La Ville.

The French adored Franklin,
especially his
anti-British politics,

and they took it upon themselves
to perform

his other lightning
experiments without him.

I've come to the very spot
where that experiment took place.

In May 1752, George Louis Leclerc,

known across France
as the Compte de Buffon,

and his friend
Thomas Francois Dalibard,

erected a 40-ft metal pole,
more than twice as high as this one,

held in place
by three wooden staves,

just outside Dalibard's house
here in the Marly La Ville.

The metal pole rested at the bottom
inside an empty wine bottle.

Franklin's big idea had been
that the long pole

would capture the lightning,
pass it down the metal rod

and store it in
the wine bottle at the base

which worked as a Leiden jar.

Then, he could confirm
what lightning actually was.

All his French followers
had to do was wait for a storm.

And then on May 23rd,
the heavens opened.

THUNDER

At 12.20, a loud
thunderclap was heard

as lightning hit
the top of the pole.

An assistant ran to the bottle,

a spark leapt across

between the metal and his finger
with a loud crack

and a sulphurous smell,
burning his hand.

The spark revealed lightning
for what it really was.

It was the same as the electricity
made by man.

It is hard to overestimate
the significance of this moment.

Nature had been mastered, not only
that but the wrath of God itself

had been brought
under the control of mankind.

It was a kind of heresy.

Franklin's experiment was very
important because it showed that

lightning storms produce
or are produced by electricity

and that you can bring
this electricity down,

that electricity
is a force of nature

that's waiting out there
to be tapped.

Next, Franklin turned his rational
mind to another question.

Why the Leiden jar made the biggest
sparks when it was held in the hand?

Why didn't all the electricity
just drain away?

In drawing on his experience
as a successful businessman,

he saw something no-one else had.

That like money in a bank,

electricity can be in credit,
what he called positive,

or debit, negative.

For him, the problem of the Leiden
jar is one of accountancy.

Franklin's idea was every body has
around an electrical atmosphere.

And there is a natural amount
of electric fluid around each body.

If there is too much,
we will call it positive.

If there is too little,
we will call it negative.

And nature is organised
so the positives and negatives

always want to balance out,

like an ideal American economy.

Franklin's insight was that
electricity was actually just
positive charge

flowing to cancel out
negative charge.

And he believed this simple idea

could solve the mystery
of the Leiden jar.

As the jar is charged up,

negative electrical charge is poured
down the wire and into the water.

If the jar rests on an insulator,
a small amount builds up in the
water.

But, if instead the jar is held by
someone as it is being charged,

positive electric charge

is sucked up through their
body from the ground

to the outside of the jar,

trying to cancel out
the negative charge inside.

But the positive
and negative charges

are stopped from cancelling out

by the glass which
acts as an insulator.

Instead, the charge just grows and
grows on both sides of the glass.

Then, touching the top of the jar
with it the other hand,

completes a circuit allowing
the negative charge on the inside

to pass through the hand
to the positive on the outside,

finally cancelling it out.

The movement of this charge causes
a massive shock and often a spark.

The modern equivalent of the Leiden
jar is this - the capacitor.

It is one of the most
ubiquitous of electronic components.

It is found everywhere.

There are a number of smaller ones
scattered around on this circuit
board from a computer.

They help smooth out
electrical surges,

protecting sensitive components,

even in the most modern
electric circuit.

Solving the mystery
of the Leiden jar

and recognising lightning as merely
a kind of electricity

were two great successes
for Franklin

and the new Enlightenment movement.

But the forces of trade
and commerce,

which helped fuel the Enlightenment,

were about to throw up a new

and even more perplexing
electrical mystery.

A completely new
kind of electricity.

This is the English Channel.

By the 17th and 18th centuries,

a good fraction of the world's
wealth flowed up this
stretch of water

from all corners
of the British Empire

and beyond, on its way to London.

Spices from India,
sugar from the Caribbean,

wheat from America, tea from China.

But, of course,
it wasn't just commerce.

New plants and animal specimens

from all over the world
came flooding into London,

including one that particularly
fascinated the electricians.

Called the torpedo fish, it had been
the stuff of fishermen's tales.

Its sting, it was said, was capable
of knocking a grown man down.

But as the electricians started
to investigate the sting,

they realised it felt strangely
similar to a shock

from a Leiden jar.

Could its sting actually
be an electric shock?

At first, many people dismissed
the torpedo fish's shock as occult.

Some said it was probably
just the fish biting.

Others that it could not be a shock
because, without a spark,

it just wasn't electricity.

But, for most,
it was a very strange

and inexplicable new mystery.

It would take one of the oddest

yet most brilliant
characters in British science

to begin to unlock
the secrets of the torpedo fish.

This is the only picture
in existence

of the pathologically shy
but exceptional Henry Cavendish.

This one only exists because
an artist sketched his coat

as it hung on a peg, then filled
in the face from memory.

His family were fantastically rich.

They were the Devonshires

who still own Chatsworth House
in Derbyshire.

Henry Cavendish decided
to turn his back

on his family's wealth and status

to live in London
near his beloved Royal Society

where he could quietly pursue his
passion for experimental science.

When he heard about the electric
torpedo fish, he was intrigued.

A friend wrote to him...

"On this, my first experience
of the effect of the torpedo,

"I exclaimed that this is
certainly electricity.

"But how?"

And to work out how a living thing
could produce electricity,

he decided to make his own
artificial fish.

These are his plans.

Two Leiden jars shaped like the
fish which were buried under sand.

When the sand was touched, they
discharged, giving a nasty shock.

His model helped convince him that
the real torpedo fish was electric.

But it still left him with
a nagging problem.

Although both the real fish
and Cavendish's artificial one

gave powerful electric shocks,

the real fish never sparked.

Cavendish was perplexed.

How could it be the same
kind of electricity

if they didn't both do the same
kinds of things?

Cavendish spent the winter
of 1773 in his laboratory

trying to come up with an answer.

In the spring, he had a brainwave.

Cavendish's ingenious answer was
to point out a subtle distinction

between the amount
of electricity and its intensity.

The real fish produced the same
kind of electricity.

It is just that it was less intense.

For a physicist like me,
this marks a crucial turning point.

But it is the moment when two
genuinely innovative scientific
ideas first crop up.

What Cavendish refers
to as the amount of electricity,

we now call "electric charge".

His intensity is what we call

the potential difference
or "voltage".

So the Leiden jar's shock was
high-voltage but low charge

whereas the fish was low voltage
and high charge.

It's possible
to actually measure that.

Hiding at the bottom
of this tank under the sand

is the Torpedo marmorata
and it's an electric ray.

You can just see its eyes
protruding from the sand.

This is a fully grown female

and I am going to try and measure

the electricity it gives off
with this bait.

I have a fish connected to a
metal rod and hooked up

to an oscilloscope

to see if I can measure the voltage
as it catches its prey.

Here goes!

Oh! There's one!

There's another one.

The fish gave
a shock of about 240 volts,

the same as mains electricity,
but still roughly 10 times less

than the Leiden jar.

That would have given me
quite a nasty shock

and I can only try and imagine
what it must have been like

for scientists in the 18th century
to witness this.

An animal, a fish,
producing its own electricity.

Cavendish had shown that the
torpedo fish made electricity

but he didn't know if it was the
same kind of electricity

as that made from
an electrical machine.

Is the electrical shock
that a torpedo produces

the same as produced
by an electrical machine?

Or are there two kinds?

A kind generated artificially or is
there a kind of animal electricity

that only exists in living bodies?

This was a huge debate that divided
opinion for several decades.

Out of that bitter debate
came a new discovery.

The discovery that electricity
needn't be a brief shock or spark.

It could actually be continuous.

And the generation
of continuous electricity

would ultimately propel us
into our modern age.

But the next step in the story
of electricity would come about

because of a fierce personal
and professional rivalry

between two Italian academics.

BELL RINGS

This is Bologna University,
one of the oldest in Europe.

In the late 18th century,

the city of Bologna was
ruled from papal Rome

which meant that the
university was powerful

but conservative in its thinking.

It was steeped
in traditional Christianity,

one where got ruled
earth from heaven

but that the way he ran the world

was hidden from us mere mortals

who were not meant
to understand him,

only to serve him.

One of the university's
brightest stars

was the anatomist
Luigi Aloisio Galvani.

But, in a neighbouring city,

a rival electrician
was about to take Galvani to task.

This is Pavia,
only 150 miles from Bologna,

but by the end of the 18th century,

worlds apart politically.

It was part of the Austrian
empire which put it

at the very heart
of the European Enlightenment.

Liberal in its thinking,
politically radical

and obsessed with the new
science of electricity.

It was also home to
Alessandro Volta.

Alessandro Volta couldn't have been
more unlike Galvani.

From an old Lombardi family,
he was young, arrogant, charismatic,

a real ladies' man,

and he courted controversy.

Unlike Galvani, he liked
to show off his experiments

on an international stage
to any audience.

Volta's ideas were unfettered
by Galvani's religious dogma.

Like Benjamin Franklin
and the European Enlightenment,

he believed in rationality -

that scientific truth,

like a Greek god,
would cast ignorance to the floor.

Superstition was the enemy.
Reason was the future.

Both men were
fascinated by electricity.

Both brought their different ways
of seeing the world to bear on it.

Galvani had been attracted to
the use of electricity

in medical treatments.

For instance, in 1759,
here in Bologna,

electricity was used on
the muscles of a paralysed man.

One report said,

"It was a fine sight to see
the mastoid rotate the head,

"the biceps bend the elbow.

"In short, to see the force
and vitality of all the motions

"occurring in every paralysed
muscle subjected to the stimulus."

Galvani believed
these kinds of examples

revealed that the body
worked using animal electricity,

a fluid that flows from the brain,

through the nerves,
into the muscles,

where it's turned into motion.

He devised a series of
grisly experiments to prove it.

Now, he first prepared a frog.

He writes, "The frog is skinned
and disembowelled.

"Only their lower limbs
are left joined together,

"containing just the crural nerves."

I've left my frog mostly intact,

but I've exposed the nerves
that connect to the frog's legs.

Then he used Hauksbee's
electrical machine

to generate electrostatic charge,

that would accumulate and travel
along this arm

and out through this copper wire.

Then he connected
the charge-carrying wire to the frog

and another to the nerve
just above the leg.

Let's see what happens.

Ooh! And the frogs leg twitches,
just as it makes contact.

There we go!

For Galvani, what was going
on there was that there's a strange,

special kind of entity
in the animal muscle,

which he calls animal electricity.

It's not like any other electricity.
It's intrinsic to living beings.

But for Volta, animal electricity
smacked of superstition and magic.

It had no place in rational
and enlightened science.

Volta saw the experiment completely
differently to Galvani.

He believed it revealed
something totally new.

For him, the legs weren't jumping
as a result

of the release of animal electricity
from within them,

but because of the artificial
electricity from outside.

The legs were merely the indicator.

They were only twitching
because of the electricity
from the Hauksbee machine.

Back in Bologna, Galvani
reacted furiously to Volta's ideas.

He believed Volta had crossed
a fundamental line -

from electrical experiments
into God's realm,

and that was tantamount to heresy.

To have a kind of spirit
like electricity,

to have that produced artificially

and to say that spirit,
that living force,

that agency was the same
as something produced by God,

that God had put into a living
human body or a frog's body,

that seemed sacrilegious to them,

because it was eliminating
this boundary

between God's realm of the divine

and the mundane realm
of the material.

Spurred on by his
religious indignation,

Galvani announced a new series
of experimental results,

which would prove Volta was wrong.

During one of his experiments,
he hung his frogs on an iron wire

and saw something
totally unexpected.

If he connected copper wire to
the wire the frog was hanging from,

and then touched the other end
of the copper to the nerve...

..it seemed to him he could make
the frog's legs twitch

without any electricity at all.

Galvani came to the conclusion
that it must have been

something inside the frogs,
even if dead,

that continued for a while
after death

to produce some kind of electricity.

And the metal wires were somehow
releasing that electricity.

Over the next months,

Galvani's experiments focused on
isolating this animal electricity

using combinations
of frog and metal,

Leiden jars
and electrical machines.

For Galvani, these experiments
were proof the electricity

was originating
within the frog itself.

The frog's muscles were Leiden jars,
storing up the electrical fluid

and then releasing it in a burst.

On 30th October, 1786,
he published his findings in a book,

Animali Electricitate -
Of Animal Electricity.

Galvani was so confident
of his ideas,

he even sent a copy of his book
to Volta.

But Volta just couldn't stomach
Galvani's idea
of animal electricity.

He thought the electricity just
had to come from somewhere else.

But where?

In the 1790s, here at
the University of Pavia,

almost certainly in this lecture
theatre, which still bears his name,

Volta began his search
for the new source of electricity.

His suspicions focused on the metals

that Galvani had used
to make his frog's legs twitch.

His curiosity had been piqued by
an odd phenomenon he come across -

how combinations of metals tasted.

He found that if he took
two different metal coins

and placed them on the tip
of his tongue,

and then placed a silver spoon
on top of both...

..he got
a kind of tingling sensation,

rather like the tingling you'd get
from the discharge of a Leiden jar.

Volta concluded
he could taste the electricity

and it must be coming from the
contact between the different metals
in the coins and spoon.

His theory flew in the face
of Galvani's.

The frog's leg twitched, not because
of its own animal electricity,

but because it was reacting to
the electricity from the metals.

But the electricity his coins
generated was incredibly weak.

How could he make it stronger?

Then an idea came to him as he
revisited the scientific papers

from the great British scientist,
Henry Cavendish,

and in particular, his famous work
on the electric torpedo fish.

He went back and took a closer
look at the torpedo fish

and in particular, the repeating
pattern of chambers in its back.

He wondered whether
it was this repeating pattern

that held the key to its powerful
electric shock.

Perhaps each chamber
was like his coins and spoon,

each generating a tiny
amount of electricity.

And, perhaps,
the fish's powerful shock

results from the pattern of chambers
repeating over and over again.

With growing confidence in his new
ideas, Volta decided to fight back

by building his own artificial
version of the torpedo fish.

So, he copied the torpedo
fish by repeating its pattern,

but using metal.

Here's what he did -
he took a copper metal plate

and then placed above it a piece
of card soaked in dilute acid.

Then above that, he took
another metal and placed it on top.

What he had here was exactly the
same thing as Galvani's two wires.

But now Volta repeated the process.

What he was doing here
was building a pile of metal.

In fact, his invention became
known as the pile.

But it's what it could do that was
the really incredible revelation.

Volta tried his pile out
on himself by getting two wires

and attaching them
to each end of the pile

and bringing the other ends
to touch his tongue.

He could actually taste
the electricity.

This time, it was more powerful
than normal and it was constant.

He'd created the first battery.

The machine was no longer an
electrical and mechanical machine,

it was just purely
an electrical machine.

So he proved that a machine
imitating the fish could work,

that what he called
the metal or contact electricity

of different metals could work,

and that he regarded as his final,

winning move in the controversy
with Galvani.

What Volta's pile showed was that
you could develop all the phenomena

of animal electricity
without any animals being present.

So, from the Voltaic point of view,
it seemed as if Galvani was wrong,

there's nothing special
about the electricity in animals.

It's electricity
and it can be completely mimicked

by this artificial pile.

But the biggest surprise for Volta
was that the electricity
it generated was continuous.

In fact, it poured out
like water in a stream.

And just as in a stream, where
the measure of the amount of water

flowing is called a current,
so the electricity flowing

out of the pile became
known as an electrical current.

200 years after Volta,

we finally understand
what electricity actually is.

The atoms in metals, like all atoms,
have electrically charged

electrons surrounding a nucleus.

But in metals, the atoms share
their outer electrons

with each other in a unique way,

which means they can move
from one atom to the next.

If those electrons move in the same
direction at the same time,

the cumulative effect
is a movement of electric charge.

This flow of electrons
is what we call an electric current.

Within weeks of Volta publishing
details of his pile,

scientists were discovering
something incredible about
what it could do.

Its effect on ordinary water
was completely unexpected.

The constant stream of electric
charge into the water

was ripping it up
into its constituent parts -

the gases, oxygen and hydrogen.

Electricity was heralding
the dawn of a new age.

A new age where electricity
ceased being a mere curiosity

and started being genuinely useful.

With constant flowing
current electricity,

new chemical elements
could be isolated with ease.

And this laid the foundations
for chemistry, physics
and modern industry.

Volta's pile changed everything.

The pile made Volta
an international celebrity,

feted by the powerful and the rich.

In recognition,

a fundamental measure of electricity
was named in his honour.

The volt.

But his scientific adversary
didn't fare quite so well.

Luigi Aloisio Galvani
died on 4th December 1798,

depressed and in poverty.

For me, it's not
the invention of the battery

that marked the crucial turning
point in the story of electricity,

it's what happened next.

It took place
in London's Royal Institution.

It was the moment that marked
the end of one era

and the beginning of another.

It was overseen by Humphry Davy,

the first of a new generation
of electricians.

Young, confident and fascinated by
the possibilities of continuous
electrical current.

So, in 1808, he built
the world's largest battery.

It filled an entire room
underneath the Royal Institution.

It had over 800 individual
voltaic piles attached together.

It must have hissed
and breathed sulphurous fumes.

In a darkened room,
lit by centuries-old technology,
candles and oil lamps,

Davy connected his battery
to two carbon filaments

and brought the tips together.

The continuous flow of electricity
from the battery

through the filaments
leapt across the gap,

giving rise to a constant
and blindingly bright spark.

Out of the darkness came the light.

Davy's arc light truly symbolises
the end of one era

and the beginning of our era.

The era of electricity.

But there's a truly grisly
coda to this story.

In 1803, Galvani's nephew,
one Giovanni Aldini,

came to London with
a terrifying new experiment.

A convicted murderer
called George Forster

had just been hanged in Newgate.

When the body was cut down
from the gallows,

it was brought directly
to the lecture theatre,

where Aldini
started his macabre work.

Using a voltaic pile,

he began to apply an electric
current to the dead man's body.

Then Aldini put one electrical
conductor in the dead man's anus

and the other
at the top of his spine.

Forster's limp, dead body
sat bolt upright

and his spine arched and twisted.

For a moment, it seemed as though
the dead body

had been brought back to life.

It appeared as though electricity
might have the power
of resurrection.

And this made a profound impact on
a young writer called Mary Shelley.

Mary Shelley wrote one of the most
powerful and enduring stories ever.

Based partly here on Lake Como,

Frankenstein tells
the story of a scientist,

a Galvanist probably
based on Aldini,

who brings a monster
to life using electricity.

And then, disgusted by his own
arrogance, he abandons his creation.

Just like Davy's arc lamp,
this book symbolises changing times.

The end of the era of miracles
and romance

and the beginning of the era of
rationality, industry and science.

And it's that new age
we explore in the next programme,

because at the start of
the 19th century,

scientists realised electricity
was intimately connected

with another of nature's
mysterious forces...

magnetism.

And that realisation would
completely transform our world.

To find out more about
the story of electricity

and to put your power knowledge
to the test,

try the Open University's
interactive energy game.

Go to...

..and follow links
to the Open University.

Subtitles by Red Bee Media Ltd

E-mail [e-mail]