TechStuff Classic: History of Electricity Part One

Did you know that engineers were harnessing electricity long before they even knew what it was? We take a look at the history and tech behind electricity.

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Episode Transcript

Speaker 1 (00:04):
Welcome to tech Stuff, a production from iHeartRadio. Hey there,
and welcome to tech Stuff. I'm your host, job and Strickland,
I'm an executive producer with iHeart Podcasts and how the
tech are you? So it is Friday, It's time for
a classic episode, which means we dive into the tech

(00:25):
Stuff archive and pull out an episode from our past
to listen to. This one, originally published on June twenty eighth,
twenty seventeen, is called The History of Electricity Heart one,
which kind of spoils what we're going to be talking
about in next week's classic episode, but you know, there's
no gain around it. I hope you enjoy this classic episode.

(00:49):
So first, let's define what electricity is, or rather, instead
of letting me define it, let's use Miriam Webster, because
that's kind of their job. Electricity is a fundamental form
of energy, observable in positive and negative forms, that occurs
naturally as in lightning, or is produced as in a generator,
and that is expressed in terms of the movement and

(01:11):
interaction of electrons. That's actually kind of a little simplistic.
It's talking about the move of electrons. It's really more
about the move of electric charge and not of electrons. Specifically,
if you had some other carrier that was carrying electric charge,
it would be more about the movement of that carrier.

(01:32):
As it turns out, electrons are the naturally occurring negatively
charged particles sub atomic particles that are concerned, especially with electronics.
So it's understandable, but I just want to point that
out that it's really more about electric charge and less
about the actual sub atomic particles. Don't worry, even though
we'll be talking a lot about electrons. I promise this

(01:55):
show won't be too negative. I'm seriously done with pun
for just a bit now. To further define electricity, it
helps if we get some basic ideas established. Now, keep
in mind these aspects of electricity were not understood for centuries.
So when I go into the history of electricity, remember
that for the vast majority of our experience working with

(02:18):
and trying to understand electricity, we did not have any
knowledge of the underpinning foundational physics. Right we were making
observations and we were even building things that could take
advantage of this stuff, but we didn't actually understand what
it was doing or how it was working, which I
always find really fascinating this idea that we can harness

(02:41):
something without fully understanding what it is and how it works.
But it's good for us, as in myself and you
guys the audience, to understand some of these basics before
we get too far into the discussion. Otherwise I have
to keep interrupting the history lesson for science lessons, and
then it gets kind of a little complicated. Some of

(03:02):
that's gonna happen anyway, but I want to get the
foundation out of the way. So the most important thing
to remember here is that we're talking electric charge, and
we want to make sure we can make sense of this.
It's time to get current on our terms. So I
guess that really wasn't the last pun I'll be talking about.

(03:24):
So electric charge comes in two flavors, positive and negative,
positive charge and negative charge. You're probably very familiar with this.
On the sub atomic particle level, pot you know, we
have our protons, those are positively charged. We have our electrons,
those are negatively charged. Now, opposite charges attract one another
in circuits. A carrier moves negative charges to a source

(03:48):
of positive charge. So some sort of sub atomic particle
needs to carry that negative charge throughout a circuit until
it can get to the source of a positive charge.
Because negative quote unquote wants to be with positive. It
doesn't really want anything, it's just that's the natural tendency,

(04:08):
right these for these two different charges to attract one another. Now,
in practical terms, the carrier is an electron. So that's
why we talk about electricity, it's why we talk about electronics.
It's the subatomic particle that possesses negative charge. So if
we do a basic electrostatic experiment where we take a

(04:28):
block of wax and we rub that block of wax
with some wool, we will build up an electrostatic charge.
So what's happening is we are imparting a negative charge
to the wax and creating a positive charge to the wool. So,
in practical terms, that means the wax has a surplus
of electrons and the wool has a deficiency of electrons. Effectively,

(04:50):
you are rubbing some of the electrons from the wool
onto the wax. That makes the overall charge of the
surface of the wax negative. It makes the overall charge
of the surface of the wall possi And if we
create a pathway that electrons can follow from the wax
to the woll. Then electrons will take that pathway pop
back over to the wool and sort of repair that

(05:14):
deficiency where that deficiency of electrons will be balanced out,
where electrons will journey back over and rejoin, and they'll
probably be a big party, you know, or at least
a sub atomic one. And that's the basics for electric charge.
So now we have to build on this foundation. There

(05:36):
are three other basic concepts that we need to understand,
and those are voltage, current, and resistance. Now these will
be important throughout the discussion of electricity, particularly as people
begin to get a deeper understanding of what was actually
happening with electricity. Voltage is probably the trickiest one for
people who aren't inclined toward electronics and electricity. It's all

(06:00):
about potential energy, specifically the potential energy represented by a
pair of different electric charges. So voltage is sort of
like pressure. You can imagine it as a force that
pushes electrons through a conductor, which is oversimplifying, but it's
helpful when you imagine it that way. So voltage is
the pressure in the system. The higher the voltage, the

(06:22):
greater the pressure, the stronger that push is a low
voltage has very little push, while high voltage has a
whole lot of push, and we need voltage to make
electronics work. Otherwise nothing is going to cause a current
to flow through a circuit. You can also kind of
think of it as potential energy in the form of

(06:42):
as an analogy of kinetic energy. So let's say that
you have a level surface upon which you've got a
two little corrals of marbles. They don't really have any
potential energy with respect to one another, they're on the
same level. But let's say you raise one of those up.
You tilt it and you raise it up, so the
corral is still holding the marbles in. But now the

(07:03):
marbles have potential energy because they're at a higher level
than the lower marbles. And then let's say you were
to connect a little slide between the top corral and
the bottom corral and allow the marbles to roll down
the hill. Well, this would be sort of like a
copper wire connecting an area that has a surplus of

(07:25):
electrons to an area that has a deficiency of electrons.
It's allowing for the movement of those electrons. Now, in
the case of voltage, we're really talking about electric potential.
Here we're not talking about kinetic energy or potential energy
that could be converted into kinetic energy. Is really just
meant as an analogy. So when we talk about voltage,

(07:48):
we talk about it with respect of two points on
a circuit. So a voltage difference between two points on
a single circuit and their potential difference really which we
may also call a voltage. The potential difference between two
points is measured in a unit called volts. No big
surprise there. A volt is the amount of energy needed

(08:09):
to force an electrical current of one ampier more on
that in a second, through a resistance of one ome
more on that in a second two at a particular temperature. Now,
you can have a voltage between two points without having
any connection between them, So you can have a voltage
between two things that do not have an active pathway
between the two. If the distance between the two points

(08:33):
is decreased, then that electrostatic field that the voltage difference
creates will intensify. If you increase the space between those
two points, the electrostatic field will diminish. So distance plays
a factor, not just the difference in voltage, so that

(08:54):
covers voltage, but now let's talk about current. So technically
the current is a flow of electrical charge, and we
commonly think of it as the movement of electrons, but
again that's an oversimplification. You can actually have a flow
of positive charge and that would still be a current.
If you add a flow of positive charge, that's technically

(09:15):
a current. But when we're talking about circuits and electronics,
we're really talking about electrons, not positively charged electrical charges,
So we tend to simplify it and say it's the
flow of electrons. Just keep in mind that is an
oversimplification because electrons are the charge carriers of negative charge. Now,

(09:37):
in a way, you could think of it as electrons
are the messengers and the electric charge they carry is
the message, and that's what's really important. But in practical terms,
we can just simplify it to electrons. We measure current
in ampiers and that gives us a sense of the
intensity or quantity of a charge. So voltage is the

(09:59):
force behind moving a charge, and amperage tells you how
much charge is actually moving. And this can help if
you start to imagine voltage as being a locomotive engine
and the amperage as being a series of train cars.
So a low amperage current you might think of as
just being two or three train cars being pushed by

(10:20):
a locomotive engine. But you might think of a high
amperage as being a series of train cars like fifteen
or twenty being pushed by that same locomotive engine. In
both cases, the locomotive engine is putting out the same
amount of force. It's just that in one case it's
pushing a relatively small number of train cars and the

(10:42):
other one that's pushing a larger number. But the amount
of force that's using for both is the same. So
that's the difference between current and voltage, or if you
prefer amperage and volts. Now, current will get a bit
more confusing when we start talking about the direction of flow,
and that's thanks to a certain founding father of the

(11:04):
United States. But I don't want to jump ahead. We'll
get there. When we get there, I'll save that for
a little bit later in this episode. Finally, we have
the concept of resistance, and as the name suggests, this
is the property of a material to resist the flow
of electric charge. A material with a very high resistance
is an insulator. It does not allow electric charge to

(11:24):
pass through it very easily. You would have to use
a great deal of energy to move an electric charge
through that kind of material. A material with very low
resistance is a conductor. It will allow electric charge to
flow through relatively easily. Now, even conductors have resistance. You
have to get to very low temperatures, like super frozen

(11:46):
temperatures almost close to absolute zero to get to super
conductivity where you have zero resistance and a conductor becomes
an ideal or perfect conductor. But at other temperatures there's
some resistance. You can get around that by making a
cable thicker. Thin cables have a higher resistance than thicker cables,

(12:06):
But that's kind of beyond what we're talking about here.
We measure resistance in Ohms and Ohm. George Ohm, who
is a physician who kind of figured all this stuff out,
developed Ohm's law. Now that tells us that voltage is
equal to current times resistance, or you could say current

(12:26):
is equal to voltage divided by resistance, or that resistance
is equal to voltage divided by current. It's this relationship
between current, resistance and voltage that is inherent in electricity
and electronics. Now, those basic concepts are the very foundation
for all electronics. Now, obviously it gets more complicated and

(12:50):
you can add in all sorts of different elements besides that,
with like diodes and things of that nature. But I
just wanted to get that covered as the basis for
the conversation that follows. And now we're going to dive
into a history lesson. So humans have known about electricity
in some form for millennia fales of Melitas, And I

(13:11):
know I'm mispronouncing that, So to all my Greek historians
out there, I deeply apologize, but I have little Latin
and less Greek. Along with my buddy Shakespeare. Anyway, he
had noted that amber, the material amber, would attract light
materials to its surface after being rubbed. So if you

(13:32):
rubbed amber with a cloth and then held it toward feathers,
for example, you had notice that feathers would have a
tendency to be attracted to the amber. Now, later on
we would understand that this is static electricity, this is
building an electrostatic charge using amber. But this was more
of an observation back in those times, and this is
centuries before the Common era, and in fact, the word

(13:57):
electricity comes from the last an electrom, which in turn
comes from the Greek electron, which means amber. So when
we talk about electrons, that means that's the Greek word
for amber. And it's because of this initial well not
even initial, but this early observation. I just thought that
was kind of interesting, and you would eventually learn that

(14:22):
a future engineer scientist named this whole process electricity in
honor of this early observation. Now in nineteen thirty six,
we're jumping ahead just to talk about another discovery about
ancient civilizations. There was a railroad project that ended up

(14:44):
excavating some ruins southeast of Baghdad, and they revealed what
we have commonly referred to as the Bagdad batteries. These
were vessels that appeared to have been designed specifically to
generate electricity. At least that's one of the hypotheses about
these these vessels. Some people disagree, but it's a very

(15:06):
popular one. Now you probably have heard about this in
some form of another or another. You may have even
seen the MythBusters episode where they talked about this. The
team in MythBusters talked about the possible applications for these
so called batteries, which could include a thing that you
would use in religious ceremonies, where you would have these

(15:26):
metal coded vessels that if you were to touch them,
you would create a circuit and you would allow electricity
to flow through you, and that would create a tingling
or numbing sensation in your hands, thus akin to some
sort of mystical experience and thus being part of a
religious experience. Or it could be that it was more

(15:47):
of a practical approach toward something like electroplating, and I
thought that was really cool. So let's talk about what
electroplating is, because otherwise, you know, it doesn't really mean
any thing to you. As the name implies, electro plating
involves using electricity to cover or plate one material with
another material. Typically you are plating one type of metal,

(16:12):
not necessarily metal, but the early version of electro plating
was metal, but one type of metal with a more
precious metal. So the reason you might do this is
to make really pretty expensive looking stuff without using too
much of the actual precious material. So you might gold
plate a copper bowl, for example, because you want the

(16:35):
gold bowl. Gold is more precious than copper, but you
don't want to actually have to go out and dig
as much gold as you would need to build a
gold bowl. So you want to plate the copper bowl
with gold. That way, it looks exactly the way you
want it to, but you didn't have to spend all
that time and effort getting all that gold. In other words,
we can thank the laziness and greed of human beings

(16:57):
for some of the early advances as as far as
electricity is concerned, So you might want to use electroplating
to do that. We also use electroplating for other purposes,
like putting rust resistant coatings onto stuff that otherwise would corrode.
You can also use it to produce alloys like bronze
and brass. But let's go back to electroplating. So let's

(17:22):
say these ancient people were using the so called Baghdad
batteries in order to electroplate gold onto copper. How would
you do this, Well, first, you have to make sure
that the copper is totally clean, because if it has
any schmutz on it, the gold will not properly adhere
to the copper and it'll flake off. So you typically

(17:42):
would clean copper this way by dipping it in a
solution that either is a really powerful alkaline solution or
a very powerful acidic solution to truly clean it. Once
you did that, you would then attach a conductor from
the battery to the copper that you're playing on electroplating.

(18:03):
So if it's a bowl, then you would want to
make sure that the terminal, the proper terminal from the
Bagdad battery is in contact with that copper bowl. Then
you would put that whole thing, the copper bowl with
the terminal into an electrolyte solution, which is in this

(18:23):
case a gold based electrolyte, so you have gold particles
within the electrolyte itself. Now, electrolytes, by the way, are
materials that dissociate into ions when dissolved in a suitable medium,
and become a conductor of electricity. So ions, of course
our variations of atoms that have a net charge on them.

(18:45):
They're not neutral. They have either a net negative or
a net positive charge. So when you do this, you've
got your gold ions in this electrolyte solution. You then
put the electrodes together so that not together, but within
the solution, and so that a current can pass through
the electrodes. Allow the current to go through the electrolyte

(19:07):
into the other terminal or the other electrode, and you've
got a negative and a positive electrode. So when the
current passes through the electrolyte, the electrolyte splits up and
some of the metal atoms contained within the electrolyte are
deposited on one of the two electrodes that you inserted
into the electrolyte. So what's really happening is the metal
atoms are ions. They hold that charge, they're attracted to

(19:28):
the electrode that has the opposite charge and they attach
to it. So if you have a negatively charged terminal
and you have positively charged gold ions, that opposite attract
rule still takes place, and the gold will plate onto
the copper electrode or bowl in this case, and then

(19:51):
you've got your gold plated copper thingam a jig, which
is kind of cool. Now, there's some who put forth
the hypothesis that perhaps ancient people's made other uses of
electricity all the way up to even powering lights in
ancient Egypt, but most scholars that I have consulted dismissed

(20:11):
this as unrealistic. I haven't really seen much evidence to
support this apart from some circumstantial evidence. Some supporters cite
a hieroglyphic relief that shows what to our modern eyes
appears to be an enormous light bulb. But the accepted
interpretation of that hieroglyph seems to be that it's a

(20:34):
lotus leaf with the figure of a snake on it,
not a huge ancient light bulb. Still, it seems that
there was at least some knowledge of the existence of electricity,
if not what it actually could do or what it was.
Now that's a trend that would last for centuries. In fact,
we were making use of electricity well before anyone really

(20:54):
knew what was going on with it. And again, to me,
that is one of the phenomenal things about human history
is when we come across these moments where people have
figured out something or how to use something without really
fully understanding why it is, that could be dangerous. Clearly,
there were plenty of cases of that in the nineteen
fifties with radiation, where people thought that radiation didn't have

(21:16):
any particular harmful effects. You might have seen things about
like using X rays in shoe stores so that people
could see their feet through the shoes that they were
trying on, and then only later did we realize that
X rays are an ionizing form of radiation and that
we probably should not or definitely should not have been

(21:36):
doing that same sort of thing with electricity. We were
putting it to use before we ever really understood what
was going on there. But of course electricity isn't ionizing radiation,
so it does have very different effects than radiation does.
But what follows is a brief history of the developments
that unfolded as very very smart people figured out what

(21:58):
the heck electricity is. So in the fifteen hundreds you
had an English physician and proto scientist named William Gilbert
who began to experiment with magnets and static electricity. So
he used loadstone, which is naturally magnetic iron ore, and
he published his work in sixteen hundred under the title
d Magnetae or Magnety. It's magneto but with a knee.

(22:26):
He was able to describe magnetism and static electricity as
distinct phenomena, though he wasn't really sure what was actually
causing it. His hypothesis was that there was some sort
of fluid or humor, as in the various humors of
the body. There was another prevailing physical theory at the time,
and that this was the cause of attraction with static electricity,

(22:48):
and that if you rubbed amber, what you were actually
doing was removing some of that fluid from the amber,
which created a hole or like a vacuum around it,
and this is why light objects would become a tra
to the amber. He called it effluvium and described it
as an electric effect. In sixteen sixty, an inventor named

(23:10):
Auto von Geirica built a machine using a globe made
of sulfur, and if you rubbed the globe as it turned,
you could build up a charge, an electrostatic charge, causing
it to attract small light objects, such as feathers or
scraps of paper. Gherica also observed that his invention would
cause a spark if you rubbed the globe for long enough.

(23:30):
You could then touch something metal like a brass knob,
and see a spark fly between the electrostatically charged object
and the grounded piece of metal. Stephen Gray, another English scientist,
observed in seventeen twenty nine that some stuff doesn't conduct
electricity at all, so he thought some materials would allow

(23:51):
the fluid of electricity to flow through, and other materials
would hamper the flow of this fluid. Electricity would which
is sort of true when you get to electrical resistance,
only we're not talking about a fluid really. Later that century,
Dutch inventor's Pietr von Mussen book and evolved von Kleist

(24:14):
created what we now call the Leyden jar, and there
are actually two variations on basic Leyden jars, which store
electrostatic charges. They're essentially capacitors, So you build up an
electric static charge in this thing, and then when you
touch the the charged component, you allow that electrostatic charge

(24:35):
to discharge to spark, so they release all of that
charged energy in an instant. Unlike a battery, which releases
uh well, which which creates the voltage difference and allows
for electric electric current to flow over time, a capacitor

(24:55):
releases it in a in a moment. The There are
two basic versions of the Leaden jar, and the first
one uses a metal container inside which you have a
glass vessel nestled inside that metal container, and inside the
glass vessel you have a second metal container nestled inside that.

(25:15):
So it's kind of like a sandwich where the bread
is metal container and the bread and the meat inside
is glass. I don't recommend eating that sandwich, it would
not taste good and probably hurt you. But it was
that layer metal glass metal, and you would then also

(25:36):
have a rod of metal that would extend up from
the base of that interior lining. So imagine like a
column rising up from that internal metal cup inside the
glass vessel, which in turn is inside a larger metal vessel.
The second variation has a metal vessel filled with a
conductive fluid like water that's got a salt dissolved in it.

(25:59):
One or on its own will conduct electricity as long
as it has some impurities in it, but you can
make it conduct electricity more effectively by adding or doping
the water with some of those impurities, and it would
have a metal rod sticking out from the water. Now,
both versions would allow you to do essentially the same thing,
which is store up that electrostatic charge. And you do
this by building up an electric static charge in something else.

(26:24):
So you might take some amber, for example, and rub
the amber. Then you would bring that into contact with
that metal bar that's extending upward from the jar. That
would introduce a charge to one plate in this capacitor,
and that would create the opposite charge in the opposing plate.
In this case, that exterior metal casing. You would need

(26:46):
to ground the outer metal case, which you could just
do by touching it yourself, or you could run a
wire from the exterior metal case to the ground or
to a metal pipe. And when you create a pathway
between the plates by touching the charge grod, it creates
a spark as the charge is able to equalize, and
that could be a significant shock, depending on how much

(27:08):
you've built up inside this Leyden jar to the point
where it could really hurt or possibly do serious damage.
Both Kleist and Muschlenbrook had shocking experiences with their respective
Leyden jars, and neither was really sure exactly what was happening.
Now we've got a lot more to talk about with
the early discoveries surrounding electricity. But before we get a

(27:31):
charge out of all that, let's take a quick break
to thank our sponsors. All right, We're up to seventeen
fifty two, and that's when we revisit the great founding

(27:51):
father I had mentioned earlier, Benjamin Franklin. That's when we
got the legendary experiments that Franklin conducted. He was friends
with a scientist named Peter Collinson over in Europe, and
Collinson had sent Franklin an electricity tube. Franklin, like his predecessors,
thought electricity was a type of fluid, and he hypothesized

(28:12):
that lightning itself was an electric spark, very much like
the kind a leaden jar could produce if you built
up enough of an electrostatic charge, and thus charged forces
would cause a lightning strike. And he further hypothesized that
you could use a metal rod to draw lightning to
a specific location, which could end up saving structures from

(28:36):
being struck by lightning. So if you had a house
and it got hit by lightning back in those days,
your house would very much be damaged, possibly burned down
as a result. So he thought, well, maybe you could
draw lightning away using long metal rods. But the problem
was he couldn't build a metal rod tall enough to
dwarf the structures. He thought that he was going to

(28:56):
have to build something that could almost reach the skies themselves,
which made it too big of a challenge, so he
came up with this idea of using a kite instead. Meanwhile,
over in France, Thomas Francois d'alabard decided to put Franklin's
ideas to the test. He actually constructed a large metal

(29:17):
pole to try and conduct electricity and declared that Franklin
was absolutely right that, in fact, that metal rod does
draw lightning. But this news didn't travel back to America
that fast. I mean, it took a really long time
for information to go from one place to another, so
Franklin was unaware that his hypothesis had proven correct. So

(29:39):
that same year, Franklin reportedly conducted his experiment using a
silk kite with a key tied to the silk kite
down to the string, and as legend goes, he flew
the kite up during a thunderstorm until the key drew
lightning to it, and then used that key to charge
a Leyden jar. So the electric charge in the key

(30:01):
was then transferred to a leaden jar, which again holds
electrostatic charge. Now, I say reportedly because Franklin's writings never
outright said that that was what happened. He never specifically
said that he himself had performed the experiment. Now, he
did say that he did a simplified version of this
plan and that it happened in Philadelphia, but it's unclear

(30:21):
who was actually flying the kite at the time. And
according to modern scientists, if Franklin had conducted the experiment
as it has generally been reported, Franklin would have been toasted.
He would have been fried scientifically speaking, So the general
theory about this not scientific theory, but you general idea

(30:42):
of what actually happened was that Franklin, if he conducted
the experiment at all, was able to pick up an
electrostatic charge by flying the kite near a storm, but
that the kite was never directly struck by lightning. It
just rather picked up a charge by being lightning adjacent.
I guess, as you could say, all quibbling aside. By
this time, it became established that lightning was in fact

(31:04):
a really big spark. Therefore part of this concept of electricity.
Franklin made practical use out of this knowledge by inventing
the lightning rod. Now, the purpose of a lightning rod
is to attract a bolt of lightning to the rod
and then channel the electricity down to the ground. This
spares structures from being hit by lightning and thus being damaged.

(31:26):
So your lightning rod typically has a metal cable that
extends down from the rod and then is bury. It
has like a conductive stake as well that's buried in
the ground, and that channels the current from the lightning
down into the ground. Or really it just gives the
current a different direction to travel, honestly, but if you

(31:46):
look at lightning, current goes from the ground up to
the sky. It doesn't matter. The point being that he
was able to figure out a way of sparing houses
by using lightning rods. So he also established something about
electricity that folks when they're first learning about it. Franklin
established electricity is having two natures. He called it the

(32:07):
resinous electricity, which he viewed as a dip in the
electric fluid from the normal amount and thus negative. So
this is where the charge is flowing too. This would
be akin to that idea of a vacuum. You have
a lack of something a hole, and thus something else
goes to fill the hole. Then there was what he
called vitreous electricity, which was an excess of electric fluid

(32:31):
and thus a positive amount. So Franklin said, the movement
of electricity goes from positive to negative. You have an
over abundance of this electric fluid and it moves to
where you have a deficiency of electric fluid. So this
is somewhat confusing if you're looking at the scientific description

(32:54):
of what's happening with your basic electric circuit where you're
having negatively charged part of that is electrons go from
an area of high concentration to an area of low concentration.
It's going from negative to positive, not positives to negative.
But it's because you're looking at two different definitions of
what is positive and what is negative. That's where the

(33:15):
real confusion lies. So when we talk about electronics and
we talk about electron flow and we're looking at it
purely from a charge perspective, we're looking at negative particles
moving toward a positive side. But let's make it even
more confusing than that. There are really two major ways

(33:35):
to illustrate charge flow in circuits. One of them is
called conventional flow notation, which is the way electrical engineers
tend to describe electrical flow, and this follows Franklin's approach.
It goes from positive to negative, so electricity flows from
the positive terminal to the negative terminal. Because we're talking

(33:57):
about the surplus of electrons to the deficiency of electrons.
We're not talking about the electric charge, we're talking about
the number. There's more electrons over here than they're over there,
So that's why this is going to be the positive
terminal with more electrons and the negative terminal has fewer
electrons because we're talking about surplus and deficiency. But there's

(34:19):
also electron flow notation now that one looks at the
actual charges, not the numbers. So in that case, the
negative terminal is where the electrons are and it flows
to the positive terminal. Both illustrations can describe the exact
same circuit, but they're going to show a difference in
what is positive and negative terminals, and so it can

(34:40):
get really confusing. Engineers tend to use that conventional flow notation,
professional scientists tend to prefer the electron flow notation, and
thus we're all left scratching our heads. All that being said,
and an enlightened person might argue that Franklin's description is
perfectly suitable if we look at other examples of electric
charge moving across an area, Because yes, in wires we're

(35:02):
talking about those negatively charged electrons, but in other substances
you might talk about protons. Or positively charged ions moving
due to a difference in charge. And because you have
these positively charged ions or even subatomic particles and their
movement can also be described as electricity, It's perfectly valid.

(35:23):
It's just not what we see with electronic circuits. So
there's that. Still a lot of folks bemow the fact
that Franklin's decision to name things as he did was
kind of based on a whim and it made things
more complicated as we learned more later on. But honestly,
there was no way for him to know at the time.
It's not really his fault, it just kind of turned

(35:44):
out that way. Anyway, back to the timeline, Since we
won't learn about electrons for a couple one hundred years
after Benjamin Franklin's work with lightning, we should just go
back to what people were experimenting with and learning about.
So a few decads after Franklin's experiments, there was a
guy named Charles Augustine de Colombe who made some significant

(36:06):
contributions to our understanding of electricity. He published multiple papers
on the subjects of electricity and magnetism between seventeen eighty
five and seventeen ninety one, and he had done a
lot of work leading up to those publications. Among his
discoveries was the relationship between the strength of opposite charges
and that distance between them. He developed what we now

(36:29):
call Coulomb's law. Now, this law states the electrical or
magnetic force depends upon the strength and nature of the
charges of the two objects and the distance between those
two objects. So, if you have two similarly charged objects,
like two positives, they repel one another with a non
contact force. Two opposite charged objects, a negative and a positive,

(36:53):
will attract one another with a non contact force. These
forces are vector quantity, which means they have both a
magnitude and a direction, and the distance between the two
objects affects the amount of force. The closer the objects
are to one another, the greater the force is between them. Or,
in other words, that the magnitude of the electrostatic force

(37:15):
of attraction between two point charges is directly proportional to
the product of the magnitudes of charges and inversely proportional
to the square of the distance between them. That's the
technical description of Coulomb's law. There's also a constant that
you have to use when you're working with equations. Using
Culolm's law, but we don't need to really dive into that,

(37:38):
the point being that he realized that distance definitely plays
a factor with these other forces that we still didn't
fully understand at that point. Then you have Alessandro Volta,
from whom we get the word volt He was an
Italian physicist who became interested in the study of electricity.
Now we normally credit Volta with the invention of the

(38:00):
electric battery, those Bagdad batteries set aside. He began by
building on the work of another physicist named Johann Carl Vilk,
who had invented the electroforts. The electrofus was a simple
capacitative generator that could build up an electrostatic charge for
use and experiments. So all these scientists really wanted to

(38:21):
study electricity, but to do that you had to build
up these electrostatic charges so that when you discharged them,
you had something to study. So this was a guy
who had developed the electro forest as a way of
making that easier to do. Volta's buddy Luigi Galvani had
observed something really unusual himself. He noted that when he

(38:41):
used two different types of metal to make contact with
the muscle of a frog, an electric current would pass
between the two, and so he thought the source of
the electricity was from the frog itself, and he called
it animal electricity. Volta disagreed, saying that the frog was
just a conductor, not the generator, and so he was
call it metallic electricity. And this was a big debate

(39:04):
in circles at the time. So in seventeen ninety two,
Volta began to experiment on metals, often using his own
tongue as the laboratory. He would put two different discs
of metal on his tongue and feel the tingling on
his tongue and say, yep, there's an electric current passing there.
But he could also use other stuff as well, and

(39:24):
he was able to observe that in fact, it was
the metals that were important, not the creature. This also
inspired Volta to look into electricity further, which culminated with
the design of the first real battery as far as
modern science is concerned. It was in eighteen hundred that
Volta invented the voltaic pile, also known as the voltaic column.

(39:47):
This battery consisted of alternating layers of zinc and silver,
or of alternating layers of copper and pewter with layers
of paper or cloth soaked in a salt solution in
between the different metal discs. This arrangement could create a
steady electric current that didn't need recharging like a Leyden
jar did. So this was a great solution for engineers

(40:09):
and scientists who wanted to be able to work with
electricity but didn't want to have to stop every time
they discharged Leyden jar to build up another electrostatic charge.
This was a steady source, so it was a huge boon,
although we didn't really have any other practical applications for
electricity just yet. But six weeks after Volta published his findings,

(40:31):
English scientists William Nicholson and Anthony Carlisle experimented with a
voltaic pile and electrodes placed in water, and the electric
current that passed through the water caused the water to
decompose into hydrogen and oxygen, breaking the molecules of water apart.
And this is a process that we call electrolysis, specifically

(40:53):
with water, but with other things as well, using electrical
charges to break those molecular bonds. By eighteen oh two,
William Crookshank had designed the first electric battery for mass production,
using copper and zinc in a wooden box filled with
an electrolyte a brine and sealed to prevent leaking. So

(41:14):
a big think of a big wooden battery akin to
something like a car battery, would be like this today.
So Volta died in eighteen twenty seven, and it was
in eighteen eighty one that the scientific community decided to
name the unit of electromotive force the vault, after him.
So he did not live to see his name used

(41:34):
to describe electromotive force, but he certainly was the inspiration
for it, and other inventors and scientists would improve upon
Volta's design, including chemist John F. Daniel and later a
physician from France named Gaston Plante, who designed the first
rechargeable lead acid battery. So Plante's design is the basis

(41:56):
for modern lead acid batteries today, like the kind you
would find in internal combustion engine vehicles. That has its
roots back in the early early to mid nineteenth century.
It's kind of incredible. Later on you would see other
improvements with battery technology. Might as well stick with that
for right now. That would include the nickel cadmium battery,

(42:16):
which was first designed by Valdemar Jungner from Sweden in
eighteen ninety nine, and the nickel iron battery designed by
Thomas Edison, or at least Thomas Edison's team of engineers
and scientists. There's always a caveat whenever you say Thomas
Edison's invention, because he had a whole lot of people
working for him who were busy research and developing all

(42:40):
sorts of different technologies, and Edison's name gets attached to
a lot of it. Edison himself was a brilliant guy,
but he largely was brilliant in bringing people to work
on these cool ideas, sometimes contributing to him directly. Sometimes
he wasn't, but he was providing the space for that

(43:00):
kind of work to happen. Anyway. He helped develop the
first nickel iron battery in nineteen oh one. But I've
talked a lot about batteries, So what I'll do in
the next section is talk about other developments in electricity.
But before I jump into that, let's take another quick
break to thank our sponsor. So one of Volta's contemporaries

(43:30):
was Andre Marie Ampere, and we talk about amps and amperage.
It comes from ampere, so his name also serves as
a type of scientific unit, basically one describing current as
opposed to voltage. Ampierre noted in eighteen twenty that a
wire carrying an electric current was sometimes attracted to and

(43:52):
other times repelled by other such wires. So he was
starting to notice this magnetic attraction along current carrying wires,
and in eighteen thirty one another fellow, Michael Faraday, explored
this idea further, and he discovered that if he revolved
a copper disc inside a strong magnetic field, it would

(44:14):
generate an electric current inside the copper disc. Faraday and
a guy named Humphrey Davey would later build an early
electric generator using this discovery. The generator consisted of a
coil of copper that would be moved past a magnet,
and this is the very very rough basic idea for
electric generators today. Moving a conductor through a magnetic field

(44:37):
induces electricity to flow through the conductor. That's the simplified version. Now.
More specifically, the greatest current flows through a conductor when
the conductor is moving through the most lines of magnetic
flux at the fastest rate. So magnetic flux is a
magnetic field passing through a surface. You've probably seen illustrations

(45:00):
of magnetic fields. Imagine a bar magnet. It's just a
simple rectangle. You have a north pole of the bar
magnet and a south pole of the bar magnet. You
would draw lines extending outward from the north pole. These
lines would start to loop back down toward the south
pole in ever increasing but less strong magnetic lines that

(45:24):
go further out until you get a couple that don't
even loop back down to the south pole. They just
go outward. So lines extend out from the north pole
and go in to the south pole, and you designate
this by drawing little arrows on the lines to show
the direction of this, the vector quality of this. At

(45:47):
the south pole, you've got all those incoming lines, including
a couple from apparently external sources. When you look at
the illustrations of magnetic fields, so if you move a
conductor through these magnetic fields, it sort of breaks the lines.
It moves through those lines of magnetic force, and you
do it quickly, current will flow through the conductor. It

(46:09):
induces current to flow, and the most current will flow
when the conductor moves through the ninety degree perpendicular plane
with respect to the magnetic field. So again, if you've
got let's imagine that the conductor is a square. We've
got a square of copper. It's not solid copper, it's

(46:30):
just a copper wire that's been shaped in the form
of a square. It's got two prongs at the base
of it that go down to where there's a crank,
so I can turn the crank and this will rotate
the square. Right now, let's say to either side of
the square, I put two very powerful magnets. One of
them has the north pole facing into the gap, the

(46:52):
other one has its south pole facing into the gap.
The squares in the center in between these two magnets.
When I turn the square so that it is perpendicular
to the magnetic field extending out from these magnets, that
is the moment when it's going to have the most
current flowing through the square as it moves. It has

(47:15):
to be moving for this to really work. When you
get it parallel with the magnetic fields, you will have
the least amount of current. In fact, you have no
current at all flowing through it at that moment. If
you keep it turning. Then you will be able to
generate current fairly consistently. It does actually pulse, it's not steady.

(47:42):
If you were to measure it out, you would actually
see it pulsing. And not only does it pulse, the
direction of current will change, so it's actually alternating current.
But we'll talk about that again in a little bit
more a little bit later. To really get into alternating
current was in eighteen thirty two there was a French
inventor named Pixie PIXII Hippolyte Pixie or Hippolyta if you prefer,

(48:11):
But he built an electrical generator based off of Faraday's
discoveries that was very similar to what I just described.
It had these permanent magnets that had a rotating conductor
that would actually really had a spinning magnet and a
steady conductor. But same principle, right, you've got a spinning
magnet and a steady conductor. You could rearrange that as

(48:32):
a spinning conductor and a steady magnet, doesn't really matter.
He found that the current's direction changed each time the
north pole passed over the coil after the south pole
had passed over the coil, and this was an early
alternating current generator, but there was no real use for
alternating current at that time, so AMPI advised Pixie to
design a generator with a device known as a commutator.

(48:56):
Commutators are meant to change alternating current to direct current.
So the difference between alternating current and direct current is
alternating current changes the direction of the current. So you'll
have electrons flowing through a circuit in one direction and
then they will reverse and flow into the other direction

(49:17):
with alternating current, and they do this many times every second.
Then you have direct current where the direction of flow
is always the same. It goes from if you're doing
the conventional flow diagram, it goes from the positive terminal
to the negative terminal, and it's never going to change.

(49:37):
It's always going to follow that. Batteries give off direct current.
Power plants that use AC generators give off AC current,
and I'll talk more about that in part two. But
why do generators create alternating current and how do commutators work? Well,
remember that example I just gave. You've got this square
rotating conductor copper wire. It's in between the two magnets.

(50:00):
Say that you've got your square position between the south
pole of one magnet the north pole of the other magnet,
And at the moment you're holding the square steady between
the two magnets, and you put a piece of blue
tape on the side that's facing magnet number one, which
has the south pole facing into the gap, and you
put a piece of red tape on the side facing

(50:20):
magnet two, which is the north pole of the other magnet.
And then you rotate the square so that it moves
down or back with respect to magnet one, and up
or forward with respect to magnet two. So if you're
staring at this, you see that blue tape start to
move down. Let's say that we've got this horizontally aligned.

(50:44):
It appears to move down with respect to the magnets.
The red tape moves up with respect to the magnets,
and as it does this, it induces current to flow
in one direction in the copper wire. But once the
square hits that parallel position with the magnetic fields and
then continues its turn, the side that was going up
is now going down through a magnetic field, and the

(51:05):
side that was going down through a magnetic field is
now going up through a magnetic field. So the red
tape takes this turn starts moving downward. The red blue
tape is making its turn and moving upward, and at
that moment, when the conductor breaks that parallel plane, the
current reverses direction. Turning the conductor quickly will induce more
current to flow and increase the number of cycles the

(51:27):
current flow reverses per given unit of time. Now, as
I said, this is alternating current, but the early experiments
for the day, they really need a direct current, not
alternating current, which means you have to find a way
to make the current flow stable in a single direction,
and that's where a commutator comes in. A simple commutator
is a split ring where the two sides of the

(51:49):
ring are made up of a conductive material, but they're
insulated from each other with an insulating material in between them.
So imagine a ring that has one tiny sliver cut
out of the ring, so it's like two halves of
a ring, and then you have an insulator in between
the two halves. On either side of this split ring,

(52:12):
you have elements that we call brushes. These are just
conductive materials that are stationary contacts. They make contact with
this rotating split ring. So as the conductor turns, so
does the split ring, and while the direction of current
changes within the conductor, the nature of the split ring
makes the flow of current and the overall circuit unidirectional.

(52:36):
Now I realize this is really difficult to visualize without help,
so I actually recommend that you go look up videos
about DC generators to get a better idea of what
I'm talking about, because a DC generator at its most
basic level is really an AC generator with a commutator
attached to it. The important thing to note is that

(52:57):
the basic generator makes altrain current and the commutator makes
it into direct current. Now, at this stage, electricity was
still something scientists and engineers would experiment with. They still
didn't have any real practical uses for electricity right now,
not on a massive scale at any rate. But over
the course of the nineteenth century it became clear that

(53:18):
electricity had the potential. It's another electricity pun for you
to change the world. I hope you enjoyed that classic
episode of tech Stuff from June twenty eighth, twenty seventeen.
Next week we will obviously have Part two, the conclusion
of this two part series on the history of electricity.
Until then, I hope you are all well, and I'll

(53:39):
talk to you again really soon. Tech Stuff is an
iHeartRadio production. For more podcasts from iHeartRadio, visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.

(54:00):
No