- How could jealousy lead to an invention?
And why would anyone be jealous
of a frog in the first place?
Well, I'll tell you.
And along the way, I'll talk about academic dishonesty,
tingly metals, reanimating corpses, scientific rivalries,
and Napoleonic politics.
I'll also show you how to light up an LED light bulb
with pennies and vinegar,
and how to make oxygen and hydrogen out of water.
Ready? Let's go.
♪ Electricity, electricity ♪
In 1791, an Italian anatomy professor named Luigi Galvani
accidentally discovered that the dead frog ugly could jump
if it was touched with a probe
that was electrified with a static electricity machine.
He then found that the leg could also move,
if it was touched with two different metals,
without any static or atmospheric electricity in sight.
In other words, the two metals with the frog
somehow created electricity.
Galvani correctly decided that electricity
was connected to life itself.
Not unexpectedly, this paper took the world by storm.
One person who was particularly interested in this paper
was Italy's leading expert in electricity,
a man named Alessandro Volta.
Volta was a loud boisterous man,
a world traveler who spoke many languages,
and was known by contemporaries as quote,
"A genius who swore and cackled over his experiments,
"guzzled and disputed over his dinner,
"electrified the ladies, and understood more of electricity
"than anyone else in Europe."
Volta first came to fame
by basically stealing another person's invention,
an object that he called the electrophorus.
In the following years, Volta made several discoveries
that are not attributed to other people,
like discovering methane,
but most of his fame came from the electrophorus
and from his oversized persona.
Volta recreated Galvani's experiments
and found it unbelievable and miraculous.
Volta then got a live frog to jump
with two different metals attached to each other
and to the frog's leg and back.
Volta decided the Galvani wasn't reanimating the frog,
as even a live frog would move with the similar metal.
He decided that the electricity
came from the different metals,
and the frog was merely responding
to the electricity produced by the metals,
just as a jump from the electricity from machines
and from lightning clouds.
Soon, it became a big debate.
Was the frog jumping because it had once been alive
or was it jumping because the two different metals
made electricity?
Soon, all of Europe split between the Voltas
and the galvanists.
By the way, both sides were partially correct
and partially incorrect.
Galvani was correct that all living things use
and produce electricity to make their muscles move
and their nerves transmit signals,
which is why if you artificially add electricity
even a dead animal will react.
Volta was correct,
in that the two metals were creating electricity,
which had nothing to do with the frog
previously being alive.
The big thing that Volta missed
was the acid in the frog's leg
that reacted differently to different metals.
In other words, he didn't realize
this was a chemical reaction
and needed a chemical, an acid or base, in order to work.
Galvani was not really a good debater for the galvanists,
as in 1797 he lost his job
and was restricted from publicly speaking
due to his objection to Napoleon taking over Italy.
Depressed and impoverished,
he died the next year from unknown causes.
One of the biggest supporters of the galvanist theory
was Galvani's nephew, Giovanni Aldini.
Aldini, despite being a professor of physics,
was much more of an entertainer than the scientist.
For example, he liked to do public demonstrations,
twitching the eyes or mouth of a cow's head,
and even a human head of a decapitated criminal.
This, for obvious reasons, gained the public's attention,
and soon galvanists throughout Europe
were entertaining crowds with these gruesome shows.
Years later,
a young woman had a scary dream about galvanists
and wrote it up as a horror story called "Frankenstein."
However, despite their public appeal,
these dramatic displays did not help much in academia.
Volta had won a prestigious British award
for explaining Galvani's experiments.
However, Volta was unhappy.
He didn't want awards for explaining other peoples' work,
he wanted award just for himself.
And he needed a decisive experiment.
But he was in a bit of a quandary,
the only sensitive equipment
to study electricity was a frog leg.
He needs to make something very powerful
with only inorganic materials.
The first thing Volta did was to determine
which metals worked the best on the poor frog.
He found that silver and zinc seemed to work the best.
If he put a piece of silver and zinc in his mouth,
on his tongue, he could feel a slight tingle.
However, if he put some together,
with wires connected to his tongue, he felt nothing.
He started to wonder if the metals had to be wet.
Therefore, he put a piece of silver and a piece of zinc
in a cup of water.
Suddenly, there was enough voltage
to be noticeable on his tongue.
He then added cups of water in a row
and got a stronger tingle.
Volta then turned the experiment on its side.
He put wet thin cardboard
between a pair of silver and zinc discs
and then stacked them together to get a pile.
And this way, he got a relatively strong tingle.
And you could get more tingling by just adding more discs.
And by using saltwater
instead of plain water in the cardboard.
If you wet your hands,
you could even feel a shock through your whole body.
(man gasps)
Here was a non-organic object,
that we create continual electricity
with no rubbing required.
In fact, Volta had just invented the battery.
He published it in 1800 to tremendous acclaim.
Of course, he didn't actually call it a battery.
A battery was a term already in use
for a set of Leyden jars,
the most powerful electrical device available at the time.
Now, Leyden jars stored and gave electricity in a jolt
and the battery gives a continuous flow of electricity.
So they are very different.
However, as Volta was trying to pump up his accomplishment,
he would often refer to his device
as resembling an electric battery.
So you can see how the name got co-opted.
Volta's victory was complete.
Napoleon was quite impressed with the device
and made Volta a count for his accomplishments.
The potential of a battery
is measured in volts named after him
and often referred to as voltage, also, in his honor.
Volta won many awards and retired a wealthy man,
never to do anything else worthy of publishing.
Interestingly, in his famous paper of 1800,
he still found the time to insult his old rival, Galvani,
who had died two years earlier,
by writing that his research was initiated because quote,
"I found myself obliged to combat
"the pretended animal electricity of Galvani."
How did Volta's pile of metal and saltwater
compare to a modern battery?
Well, to answer that, I need to talk about two things,
voltage and maximum current.
Voltage is like the power in a water pump
that adds water pressure to your pipes.
It is there even when no water is flowing.
The battery in your cell phone has 3.7 volts of potential.
Typical pile that Volta used
would produce five, 10, and even 20 volts.
You can actually make your own pile quite easily
with copper pennies, zinc washers,
and paper soaked in vinegar.
Just like Volta, you can pile up the zinc,
vinegar-soaked paper,
and pennies to make a homemade battery.
This pile of just 10 pennies
creates an astonishing eight volts of potential.
So can I power my cell phone with a bunch of pennies?
Unfortunately not.
It has to do with something called current.
Current is like the amount of water flow
you get from the pipes.
There are two numbers with the maximum current,
one is the amount of current you can get for a second
before the battery breaks down or even lights on fire.
That is not really a useful number.
The other number is a vague number,
the amount you can safely get flowing steadily
for a long period of time.
And that is what you need to run your phone.
Your phone probably uses between
100 and 400 milliamps of current,
to talk and text and what have you.
The most current you can get from a voltaic pile,
even for a second, is around 15 milliamps.
The maximum you can get to steadily flow
is around 1/2 milliamps, which is not very much,
and nowhere near enough for your phone.
However, is more than enough
to light up a little LED light bulb.
Pretty magical, huh?
So what did people do with Volta's battery
before the invention of the LED light bulb?
Well, they could give themselves shocks
and they could animate dead animals and people,
but the most useful thing they did with batteries
in the early 1800s has to do with chemistry.
See, in the same week, Volta published his work,
a pair of English friends
accidentally put the leads from a battery
in two container of water.
Soon, the leads started to make bubbles.
One probe would get bubbles of hydrogen
and one probe would get bubbles of oxygen.
Plus, you had about twice as much hydrogen as oxygen.
They had proven the water was made of H2O.
This experiment inspired a young
and handsome chemist named Humphry Davy
to make the world's strongest and largest battery,
with over 2,000 plates of copper and zinc in an acid bath.
From 1807 to 1808,
Davy managed to electrically isolate eight new elements
and increase the total number of known elements by 20%.
Humphry Davy's story is a story of how good looks,
dramatic demonstration, and prolific drug use
made him a scientific superstar.
And that wild story is next time
on "The Secret History of Electricity."
♪ Electricity, electricity ♪
Thanks for watching my video.
Please remember to give it a nice thumbs up.
Also, in the comments,
I included how to make your own voltaic pile,
as well as how to get hydrogen and oxygen out of water.
Both are very simple experiments to do.
Also, if you're interested in learning more
about Galvani in his frog,
check out my video on "Luigi Galvani Made a Dead Frog Jump."
If you're interested in how a battery works,
check out my video, "How a Battery Works:
"A Fun and Simple Explanation for Adults."
And make sure to check out that video about Humphry Davy,
who's a very interesting person in his own right.
And he also ended up hiring Michael Faraday,
who really changed the world of electricity.
Either way, join my YouTube page, Kathy Loves Physics,
my Facebook page, Kathy Loves Physics,
or check out my webpage, www.KathyLovePhysics.com.
Okay. Have a nice day.
(jazzy upbeat music)