September 27, 2019 • 51 mins
Who really invented the light bulb? What is the Draper point? How do fluorescent bulbs work? Join Chris and Jonathan as they shine some light on the fascinating story of light bulbs.
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Speaker 1 (00:04):
Welcome to tex Stuff, a production of I Heart Radios,
How Stuff Works. Hey there, in Welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
How Stuff Works and I heart Radio and a love
of all things tech, and it is time for a
classic episode of tech Stuff. This episode is one I
(00:26):
referenced in a very recent episode of tech Stuff. In fact,
it maybe so recent that I don't know if it's
published yet or not. It's called tex Stuff Gets a
Bright Idea, and it's all about the real history of
the light bulb. We often hear that Thomas Edison invented
the light bulb, but did he for real z s though?
(00:47):
We find out in this episode. Hey there, I just
looked up and there he was doing that thing, getting
my get my energy up. Actually, one of the things
that uh, you know, we start the episode of pretty traditionally,
one of the things that we had as an early
ritual as we recorded Tech Stuff was Jonathan and I
would be sitting here in the virtual darkness and someone
(01:10):
we had different engineers over the time over the years now,
but someone would come in and turn on the lights, yes,
and usually lighted begs, but we wanted to talk a
little bit about light, specifically light bulbs today. So what
a brilliant idea of those were? You know before lightbulbs,
Before light bulbs, there was no way to indicate that
(01:32):
you had an idea. Yeah, yeah, there's no there's no yeah,
pre light bulb there was no ting. Before we get
into how lightbulbs work in their history and everything, I
want to lay down a little physics for you. All right,
go ahead and enlighten us. See what you did much?
(01:52):
So we are talking about light and what is light? Well,
light is made up of these very tiny part of
all like packets called photons. They've got energy, they have momentum,
but there's one thing they do not have charge accounts
mass or I was going they have no mass, but
(02:16):
not no moss. Photons are these packets of energy. They
have momentum but not mass. And these particles, these these
photons are emitted by atoms. Once you have excited an
atom to the point where it's electron starts to move
out of its normal orbit and goes into a further
(02:39):
orbit from the atoms nucleus. And once once you remove
the energy source from that atom, the electron will eventually
return to its normal orbit around the nucleus. But it
has to it has to get rid of that energy
that you have pushed into it. Right, energy is not
created or destroyed, it's just transferred. So this electron, as
(03:02):
it's coming back down to its normal orbital is going
to shed off energy. And in this case, the energy
is in the form of photons. Now, photons are going
to be emitted in the entire spectrum of light. Now, humans,
we are capable of perceiving a narrow band of that
spectrum called the visible spectrum because it's visible to us. Oh,
(03:28):
I always wondered about that. This is where the whole
roy G BIV thing comes in. Right. The different wavelengths
of light dictate what the color is as we perceive it. Uh.
The but the the light goes well beyond outside the
the visible range. There's things like ultra violet and infrared,
and then you get into electromagnetic radiation as you go
further out. But and anyway, Uh, these photons can come
(03:52):
into various forms, so you can have of infrared photon
or ultra violet photons. So, uh, if it's in the
visible light spectrum, we're able to see it. Now that's
important because that's the whole basis of creating a light bulb,
as you want to create some sort of device that
(04:13):
you can use to create photons so that you can
illuminate an area, and before light bulbs, you didn't really
have that option unless you set something on fire. Uh,
And there's a limited number of things we can set
on fire before we set ourselves on fire or we
run out of stuff that is flammable. So it was
a good idea to try and develop something that could
(04:35):
create light in another way. Now, Uh, how do we
know about how what is the principle upon which light
bulbs work. Well, again, if you excite an atom and
you push those electrons out, when the electrons come back in,
they emit photons. If you give enough energy to an object,
(04:59):
then you can it enough uh photons for it to
be within the depending upon the nature of that material,
for it to be within the visible spectrum for it
to be perceptible. Because even if it's in the visible spectrum,
if the energy is not great enough, you won't be
able to see it. And we're all emitting energy all
(05:19):
the time, like humans are emitting infrared energy all the time,
and if you had an infrared camera, you would be
able to see it even in a perfectly dark room.
You look at the infrared camera, look at a person,
you would see light as interpreted by the sensor in
that camera and converted to visible light for us to see.
You would be able to see that person because they're
emitting that infrared light. Well, we may even depending on
(05:42):
what what, depending on the material, it may even be
emitting visible light, but it might be emitting at at
levels so low as to be imperceptible to humans. So
if you add more energy, you can boost that and
actually see the visible light. Uh. And this can happen
with things like soled materials. And there was a fellow
named John William Draper who in seven demonstrated that solid materials,
(06:09):
almost all of them, will glow once they reach a
temperature of seven kelvin. Kelvin's a scientific scale for temperatures.
Kelvin is what we have when you get to zero
kelvin that says that's as cold as you can get.
It actually refers to molecular movement, and at zero kelvin,
(06:30):
there is no molecular movement. So that's like the deepest
depths of space. Where there's nothing absolutely absolutely uh So,
if you wanted to convert that into degrees that we're
more familiar with most of us anyway, it would be
about five and twenty five degrees celsius or nine seventy
seven degrees fahrenheit. And at that temperature, solid materials will
(06:54):
start to glow. We call it the draper point. Now,
in order to have a object glow at a uh
at a at an intensity bright enough for it to illuminate, say,
a room, you will have to put in more energy
than that, right, because this is talking about they start
to glow, but that doesn't mean that they're glowing so
brightly as to illuminate an entire room. That's where it starts.
(07:17):
So but you know, you've you've probably seen this. If
you've ever seen a blacksmith work, then you know the
blacksmith might be heating up iron and when they take
that out it's glowing red. Or a glass blower or lava.
You know, there's lots of stuff that tends to lava.
It's not all man made, but there's lots of stuff
out there that um that that demonstrates this. So that's
(07:42):
the principle. But but the idea behind an electric light
source actually predates Draper's discovery. Really, yes, back in well
the early eighteen hundreds. I've seen I've seen reports from
eighteen o six all the way up to eighteen o nine.
There's some discrepance's there. But an English chemist and inventor
(08:03):
named Sir Humphrey Davy, named Humphrey Davy, he was designated
a night So that's the sir. He connected a battery
to a strip of charcoal and he used the electricity
to actually heat up the charcoal to the point where
it started to glow, which created technically the first electric
(08:24):
arc lamp. Uh. This was not a viable means of
illumination as it was hard to do. It required a
lot of energy. The battery drained really quickly, the carbon
burned at such a or it got so hot as
to be incredibly dangerous for uh, say, I don't know
(08:47):
a typical house. Um. So it was not something that
was going to immediately be adopted into every household, but
it was proving a concept. Uh. Also, by the way,
sir very Davy did go on to invent many things,
including the Davy lamp, which was not an electrical lamp.
It was a gas lamp. There was a gas lamp
(09:08):
that had a mesh screen that would surround the flame,
so that miners meaning people who mind the earth, not
people who are underage miners, could take the lamps, although
depending in England at that point in the time, the
two may have been the same. Hey, our history has
not always been a nice one. But the miners could
(09:30):
take a lamp down below the ground and even if
they encountered a pocket of gas, the mesh would actually,
this fine mesh would prevent the gas and the flame
from making friends and becoming a big boom. Very important
for miners of both types. So the he did invent that. Again,
(09:51):
not electrical, but I thought it was an interesting aside.
Moving ahead back in one Frederick de Moulins, and I'm
sure I have completely mispronounced his name, and I apologized
profusely for that. Another Englishman, Yeah it could be. He
patented a lightbulb in eighteen forty one, and this one
(10:12):
was comprised of a glass case and a burner or
burners actually made of carbon and in expensive material you
may know as platinum. Yeah, you thought that led light
bulbs were expensive, so uh he he patented that design
again not really practical for for every day or even
(10:34):
industrial use. An American inventor named J. W. Starr received
a patent for a light bulb that used a carbon burner. UM.
And then the next few decades were spent among inventors
trying to find a way to perfect the discoveries these
earlier inventors had found, so that you could create a
(10:55):
light bulb that made sense, that that was a ficient
that could light well, that was not going to be
prohibitively expensive. And there are two names in particular that
pop up all the time, one of them being probably
the most famous, uh connected to the light bulb, which
is Thomas Edison. Yes, it's funny. As we were recording this,
(11:18):
we are rapidly approaching the hundred thirty third anniversary of
the first test of Edison's incandescent light bulb. Yeah. Now,
it is important to note Edison was not the person
who invented the light bulb. He was not even the
person to invent the incandescent light bulb, but he was
someone who perfected that design and made it viable as
(11:39):
an actual product. Yeah. Now it's it's important to know,
um that these these early light bulbs. Uh, you know,
not only were homes not really wired. Actually, the light bulb,
I would argue, based on my research the over the past,
you know, the past times that we've done tech stuff.
We've talked about Edison and Tesla and all these the
(12:00):
lightbulb actually was sort of the key to getting homes
wired for electricity. Yeah, I mean you and it made
sense because suddenly you had households that could be uh
safely with air quotes around that lit after dark and
extend the useful uh time human being could get stuff
(12:22):
done because otherwise, when night fell, we might as well
just go to bed because it was gonna be pretty dark. Well,
you know, we're related bed and early to rise, as
they say, early to bed, early to rise, because otherwise
you're barking your ship on the coffee table. Well, yeah,
that's that's true. Well, gas lamps, uh were very very popular.
(12:43):
But they were I mean, in addition to being obviously
inherently somewhat dangerous um and oil lamps, but they were
um smoky, um. They were dirty. So you know, I'm
sure they probably didn't smell all that great um. But
the problem with these early lightbulbs is that they weren't
(13:04):
very practical. Okay, look, I got Yeah. There was another inventor,
an Englishman, the Englishman named Sir Joseph Swan who was
working on light bulbs around the same time as Edison,
and Swan's bulb used carbonized paper as the burner, which
worked pretty well except that it didn't last terribly long.
(13:25):
And in fact, this was a problem that a lot
of lightbulb researchers were encountering that including Edison. The first
problem was, all right, well, we've we've found uh that
if you if you run enough electricity through some sort
of object, you can heat it up enough so that
it begins to glow. But if that item is exposed
(13:49):
to oxygen, then it will burn. So even if you
found a material that does not melt at a high temperature,
it would burn, It would combust at a high enough
temperature because it, you know, it would be adjacent to oxygen,
which you know that that's part of the fuel you need,
you know, in order to have a fire. UM. So
(14:09):
the you had to close it off from oxygen, which
is why there were these these vacuum tubes essentially is
what they create, these vacuum containers. UM. But Once they
got through that, they had to find what's the right
material to use. Actually, what Edison ended up using at
first was bamboo. He took Japanese bamboo and carbonized it
(14:34):
and created a filament. And in this case, what a
filament is is this really long, long, long, long strip
of material that is then coiled so that you can
decrease the space that it needs to um to fit
into whatever you want to put it in. So it's
got a lot of surface areas. Then the resistance is high.
(14:56):
A resistance in electricity is the the materials resistance to
electrons flowing through it freely. The more resistance there is
in general, okay, you've got greater resistance, you have greater heat. Well,
the secret to the light here is the amount of
heat that's being generated. That's the energy that is creating
this whole system of electrons being pushed out and then
(15:17):
when they start coming back in, the photons are being
let out. So let the photons out? Who let the
photons out? That was as an a swan as it
turns out. Um. It's interesting because then Edison Edison ended
up hiring what his first his first light bulb design
used a temperature controlled switch to try and keep the
(15:40):
material at the right temperature so that it would the
light bulb would remain lit longer, because I was an
early problem with these light bulbs is that their their
utility was low because they couldn't couldn't burn them for
very long. But this was a problem because the the
temperature control controlled switch, once a certain temperature was hit,
it switch off right the light would go off, And
(16:03):
so I started creating this flickering problem and made the
bulb practically unusable. So he then hired a physicist from
Princeton named Francis Upton, who led Edison's research team working
on light bulbs, to start practicing with other stuff. That's
when they came upon the idea of using the bamboo
as a filament. Um. Swan and Edison ended up battling
(16:27):
each other. Edison ended up taking patent lawsuits against Swan,
but then ultimately the two of them formed a partnership
together and they created the Edison Swan United Company. Teamwork teamwork. Um. Yeah,
just so, just so you guys know, patent wars are
not a new thing. Oh no, not in the least. Um. Yeah,
(16:49):
it's funny. While while carbonized bamboo sounds like an ingredient
for a hipster sandwich. Um, it did have the ability
to burn for more than which you know back in
that time, that was pretty nice for a for a
light bulb. Yeah, and uh, this served as the basis
(17:10):
for what future light bulbs would be and then we
ended up shifting to a different type of filament. But
we'll get into that in a second. So let's talk
about the basic anatomy of an incandescent light bulb. And
don't worry florests and an l e defense. We're going
to get to you too. You just sit tight. So
the incandescent bulb, you've got two contacts to two electrical
(17:35):
context on this on a typical incandescent bulb. One of
them is at the very end of the bulb, that's
the base of the bulb, and the other is in
the actual treads that you screw into your um light
bulb sucket. Yeah. Actually usually has a squeaky noise which
has that perfect pitch to give me the heb gbs.
(17:59):
It's like the finger nae else on the chalkboard type thing.
It's like almost every single light bulb in my house
makes that noise. And so it's a physically demanding task
for me because well, I guess psychologically really more than physically,
because I I suffer trauma. One follows the other. You
start to how many how many Jonathans does it take
(18:20):
to you screw the light bulb? Well, after the first one,
it takes a few others to calm them down. Yeah,
I'm not afraid of the dark. I'm just afraid of
changing light bulbs. So that's not really true. I just
don't like doing it. But anyway, these metal contacts are
what create the the circuit, right, so that the circuits
complete when these two contacts are are in contact with
(18:44):
the rest of the electrical system. To one um, the
contacts are attached to some wires and those wires are
attached to the filament. Now, in this case, the filament
is no longer bamboo. For your typical incandescent, it's usually tungsten.
And the reason why it's tungsten is a couple of
(19:05):
different reasons. One is that the melting temperature of tungsten
is really high, so you can heat tungsten up quite
a bit and not worry about it being um melting
away that that that's obviously another issue with light bulbs. Right,
you heat up materials, some material is gonna melt, and
it might melt before you hit that draper point, which
(19:25):
would be bad because you wouldn't get any light out
of it. You would just get a you know, a
glass cylinder of hot molten sludge. Um hot molten sludge
would be a great name for a band. It is.
It is, however, very thin. The filament is very thin,
as anyone who has uh smacked a light bulb hard
(19:46):
enough to break the filament but not hard enough to
break the glass knows that's really annoying. That's another really
annoying thing about changing light bulbs. Oh man did I Yeah,
just ruined it perfectly good by bulbs. So yeah, it's
very thin again, that's to increase resistance. That's another thing.
Is that a a a copper wire, for example, the
(20:10):
the greater the diameter of a copper wire, the lower
the resistance. So if you have a very um thin
copper wire, the resistance is greater. That means it's going
to also generate more heat as a result. Well, this tungsten,
same thing. I mean, this same principle applies across all materials.
Tungsten filament is very very very thin. It's actually coiled twice.
(20:33):
The first coil is done to decrease it's you know,
the length, and then after you've coiled it once, you
coil it a second time around. Uh. These these support
wires and UH that helps when the tungsten heats up,
it starts to generate, you know, give off these photons. Uh.
(20:53):
It helps, uh concentrate that light so that you have
enough for it to be useful. Because again, you want
to give enough energy there for you to have visible
light that you can actually see stuff by, but you
don't want to have to pour in more energy than
was necessary. And we should point out incandescent bulbs not
terribly efficient. No, we think about heat being a a
(21:15):
wasted form of energy in this case, and how hot
and incandescent bulb gets. And it's also giving out photons
outside the range of visible light, so you're getting you know,
infrared light and maybe even ultraviolet light from from these
light bulbs. Well that that means that again it's a
drop in efficiency. I mean, yeah, it's giving off light,
(21:36):
but we can't see it, so it doesn't do us
any good, not not in a normal application. Anyway, you know,
if you're doing something that required infrared or ultraviolet light,
than sure, although there are better ways of doing that
than using a regular incandescent light bulb. I mean you
you could you could even cook brownies with it, which
is with an easy bake oven. It's funny because I
(21:58):
don't think people not everyone realizes this. It's not like
a secret. But um, the the older easy bake ovens, especially,
they're they're essentially using the heat from a lightbulb to
cook uh, you know, very simple cakes and brownies and
things like that. Right now, the you know, you might
ask what's inside a lightbulb? Besides all this stuff, there's
(22:20):
actually a gas that's inside most incandescent light bulbs, and
it's usually are gone, which is an uh it's an
inert gas, meaning it does not react to other stuff. Hey,
are gone gas. That's a tornado outside. Yeah, So like, oh,
you never do anything now that you want it to
be inert because obviously, like something like oxygen, then the
(22:41):
tungsten would start to burn. It would dramatically decrease the
life lifespan of your average light bulb. So they pump
the oxygen, they pump air out of the glass. Globe
and fill it with are gone gas. Yep. And so
you might say, well, why why not just have a
vacu mist of argon gas. The reason for that is that, uh,
(23:04):
at that high temperature, you have another problem besides combustion,
even if you don't have auction, the other problem is evaporation.
Atoms from the tungsten will actually evaporate off the filament
because of those high temperatures, and over time that means
that you're losing you know, every time you're using that
light bulb, you're losing tungsten. With the old light bulb, Yeah,
(23:25):
and with the old light bulbs, you would actually have
the tungsten start to evaporate away and coat the inside
of the light bulbs, So the light bulb would get
more and more dim both because there was less filament
to light and because all the filament that was gone
is now coating the inside of the light bulb making
it darker. So by using argon, what it actually acts
(23:46):
as a sort of a sort of a barrier. These
atoms from tungsten will come off the filament, bump into
a an argon atom, and then because argon's a nerd,
it's not going to act with that. That um energy,
or that that particle rather the particle then returns to
(24:07):
the strip of tungsten um. So it acts as kind
of a cushion. It's just pushing the the atoms back
to the tungsten. Keeping that filament last to last longer
very important. And so that's the basic premise behind these
incandescent bulbs. They you know, they get to a pretty
(24:29):
hot temperature. We're talking around degrees celsius or four thousand
degrees fahrenheit um. Because again, you want to put out
enough visible light for it to be useful. Now that
all depends on the wattage of the bulb. Yeah, which
generally speaking, you can think of his brightness, um, it's
(24:49):
it's kind of or or really you can think of
his brightness or how hot that tungsten's getting inside the
light bulb. That's what that kind of translates into. Uh
and UH interesting. We have an article on the site
how light Bulbs Work and how stuff Works dot com.
Great article, great illustrations, a fun read. I mean, I
(25:11):
really do think that it's actually you would think it's
an article about light bulbs, but it really is a
fun read. And one of my favorite UH facts in
this is that a typical sixty what bulb has a
tongusten filament that is six and a half feet or
two meters long and one hundred of an inch thick.
(25:31):
I don't have the centimeters for that, sorry, but it's
you know, six and a half feet long or two
meters And if you were to completely uncoil that filament, however,
once it's all double coiled, it's in a space that's
shorter than you know, the tip of your pinkie finger,
and you're thinking, wow, that's to go from six and
(25:53):
a half feet to that is pretty impressive, you know.
And again that's packing all that material and so it
can give off enough light for it to be useful.
I just got my own bright idea, which means a
light bulb just went off over my head. And that
idea is, will now take a quick break, do you uh?
(26:19):
If you happen to know how three way light bulbs work.
I do not. Actually, as a matter of fact, we
have another very very short article on how three way
light bulbs work, and they also have two filaments. Um,
it's it's very interesting. Now the socket has to accommodate
that because it has to do also with a connection
(26:40):
on the outside. But essentially what happens is that the
socket is, you know, through a switch, providing instructions on
which of the two filaments to light. So for the
first on switch, if you ever use a three way light,
you know that the first one is the lowest setting
uses the least amount of electricity. Well, the one filament
that is designed for that lower setting comes on when
(27:03):
you click the switch. Again, that provides instructions for the
second filament, but only the second filament to come on,
and then the third the two team up. I see,
So that and then that the off got you. You
get these the sum total of light coming from the bulb,
which is, if you'll pardon upon a brilliant way to
do that because it's very simple, shiny. So moving on.
(27:25):
That's a little just aside and firefly reference for you
guys out there. And of course you can achieve different
effects to what the kind of glass you might be wondering,
you know what the natural lighting or the what does
the blue what's the blue one do? Well, it's it's
just diffusing the uh photons given off by the tungusten
inside the light bulb a little bit different and I
(27:47):
should point out a neat that depending upon the material
you're using, that will determine what kind of light is
given off. Right, So tungsten's giving off this light, uh,
partially because of the fact that it's tungsten. But other
materi areals give off different kinds of light, different colors
of light along or or essentially lights that are different wavelengths, right,
(28:08):
so different parts of the spectrum, sometimes visible, sometimes not. Uh.
This is used in chemistry, it's used in astronomy, it's
used in lots of different areas of physics, not just
in creating light bulbs or you know, heating stuff up
until it glows. But that kind of that's kind of
the full discussion on incandescent bulbs. But those aren't the
(28:28):
only kind of bulbs we have. We also have fluorescent bulbs. Yes. Um,
you might say, well, you know, uh, Edison and later
the company that he was directly slash indirectly the founder
of General Electric, you know, perfected the the incandescent light
bulb and uh uh you know you would think that
(28:50):
they would be very upset that the fluorescent came out.
Well not really, because, as we touched on on our
famous or infamous GE series How How Influence Famous? That's
more than the series on G E G. E was
actually in development of the fluorescent light bulb. Yeah, so
fluorescent lightbulbs use a different method of generating light, so
(29:14):
you're not you don't have that physical filament inside a
fluorescent bulb. Instead, what you have is a sealed glass tube.
By the way, we also have how fluorescent lamps work
at how stuff Works dot com. So again you should
read that if you're interested to learn all the physics
involved in this. But in general, you've got a sealed
(29:34):
glass tube and not the animal that Chris was alluding
to earlier. It's just completely sealed. Uh. The tube has
inside it's some mercury and there's also an inert gas
like again are gone. Uh. The inside of this glass
tube is coated with a powder that's phosphorus. Now, phosphorus
(29:57):
means that when light stri exit, it gives off light.
So that sounds like it could be totally useless, except
we're talking about light within the entire spectrum. So even
if if you have a certain kind of phosphor, it
will um if you were to hit that phosphor with
(30:19):
light that's outside the visible spectrum. For example, ultraviolet light,
and then that phosphor actually emits visible light. That becomes
useful because you can either look at stuff that is
in the presence of light that's otherwise outside our our
field of vision, or you can create something like a
fluorescent light bulb that uses light outside of our vision
(30:43):
to create light that's inside our vision. The way this
works is you've got the electrodes at either end of
this tube that are wired to some sort of circuit. Now,
the circuit, once we turn that on, starts to introduce uh,
free flowing electrons into the gas. Now this is different
from the filament approach because then you have electrons running
(31:06):
through a material directly right, just like you would a
wire in a circuit. I mean, that's essentially what it
is with this. It's free flowing electrons going through uh.
The gas in this case AREGNE. It takes a little
while for these electrons to be introduced into this this tube,
which is why when you turn on most fluorescent light
(31:27):
bulbs there's this little flickering moment while it's coming on. Ye.
The cause, again, the the has to introduce the the
free flowing electrons for this to work. So once these
electrons with considerable voltage are introduced. UH, the energy starts
to change some of the mercury that's in that tube
(31:50):
from liquid to gas. Now, again, when we're introducing electricity
into or energy into an atom, it's exciting those electrons,
pushing them out of their orbitals. UH. And then when
the electrons start to come back down to their normal
orbital they'll give off photons. With the case of mercury,
(32:10):
you're talking about light photons that are in the ultra
violet wavelength range. So again you can you are exciting
the mercury and it's giving off ultra violet light. We
can't see ultraviolet light unaided anyway, we're incapable of seeing
light at that wavelength. But by coding the inside of
(32:30):
that tube with phosphors that are able to absorb ultra
violet light and then emit light in the visible spectrum,
we can use that ultraviolet light two give us light
we can see indirectly. We have this intermediary step with
the phosphors. So the mercury starts to go from liquid
(32:51):
to gas, gives off these ultraviolet photons. The ultraviolet photons
hit the phosphors. The phosphors absorbed the ultra violet light
and emit light in the visible spectrum, and voila or
viola if you prefer, we have ourselves a fluorescent light bulb.
By the way, if you have a black light, you
essentially have a fluorescent bulb that does not have those
phosphors necessarily on the inside, because it's just emitting the
(33:16):
ultra violet light directly. And then you can have those
wicked uh van posters light up in pretty colors. All
in all, you're just another brick in the wall, thank you.
So uh yeah, I mean that's the that's the essential
way that fluorescence work. And this is also why because
(33:36):
they contain mercury why they are so dangerous or potentially dangerous,
because mercury is toxic, and if you were to say,
I don't know, drop a palette of fluorescent light bulbs
in a warehouse, you could have a potentially dangerous situation
on your hands because you could know very much have
(33:58):
enough mercury there to suffer mercury poisoning. Yeah, it's um.
It's in a way sort of amusing that so many
of my friends remember busting fluorescent lightbulbs uh fondly because
they make out, they make a loud noise. I had one.
I was in a bookstore once when uh, and I
(34:19):
was just perusing some books, so I'm very much focused
on what I'm doing when the employee behind me, who
was trying to change out a fluorescent bulb, accidentally dropped
the one in her hands from a ladder and it
landed directly behind me. And I thought I had just
been hit by a shotgun. Okay, turned out I wasn't
(34:40):
well and and and at that time, it wasn't uh
popular knowledge. I probably shouldn't say common knowledge, but popular knowledge.
People just didn't know, uh, that there was mercury in there. Now,
I mean, admittedly there's not a boatload of mercury in there,
but you know, it could it could be something serious.
And that's why in your fluorescent light spurned out, it's
(35:02):
a good idea to find someone who can take it
and recycle that, not only for safety reasons, but also
because you know they can recover some of that material. Now,
when you're talking about the fluorescent light tubes, UH, that's
pretty much it. I mean you've got the uh, the
tube of gas with the caps on the end, and
you plug it into the uh the light fixture to
(35:24):
have it work. Well, there's there's other stuff underneath that
that you may not necessarily see. It's it's covered up
by the fixture. UM. One of the most important parts,
I would argue is the ballast, which is a type
of transformer UM that basically ups the electricity to make
it work better with the fluorescent light, because again, you
(35:46):
have to introduce those ions, which is not necessarily easy
to do, especially since you've gotten a neert gas in there.
We're gonna take another quick break here in a second,
and then after we come back, Chris and I will
shine a little more light on this subject. So if
(36:08):
you ever looked at a compact fluorescent line or curly bulbs,
I like to call them UM because I like to
do that UM and wonder what the heck the big
honking bases that you have to screw into a regular
light fixture. That's where the ballast is. The ballast is
built into the base of that UH, that fixture, UM,
(36:31):
which is why it may or may not fit into
that incandescent and that that fixture that you bought that
would allow you to use a UM a typical incandescent bulb.
Now they say in some cases that you should not
use those because they do generate heat and that can
uh make the ballast overheat, uh, cause a short circuit
(36:52):
and possibly fire. You know, it depends on what kind
of fixture you have, so keep an eye on that.
But if you've wondered what that what that situation is, um,
it's built into the ballast, and the ballast is also
in that case what controls the three way There are
some three way fluorescent compact fluorescent whites. Um. The ballast
is what makes that possible because it can control the
(37:15):
amount of electricity going into the tube. Yeah, it's also
important to point out that another big difference between using
free electrons moving through a gas. Essentially you're talking about
ionized gas or plasma. But I know if you're using
free electrons moving through a gas, it does behave differently
than it would if those electrons were moving through a wire. Uh.
(37:39):
Now with a wire, you know you have the resistance
is dependent upon the composition and the size of the wire.
In a in gas discharge, which is in the terms
of this not something that's gross is uh, it's the
resistance actually decreases due to current. So when you've got
(38:01):
a current going, the resistance begins to decrease through this
gas that's more electrons and ions start to flow through.
They bump into more atoms, free up more electrons, creates
more charged particles. So the resistance is UH is constantly
decreasing as long as that currents on, and that can
be a problem. If that continues for too long, it'll
(38:23):
blow out the electrical components of the the the entire system.
So that's another reason why these ballasts are important. They
are little safety features that control that so that the
current doesn't continue indefinitely. It stops briefly, but not so
briefly as to make the lightbulb turn off, or at
(38:46):
least if it's turning off, it's turning off at a
rate so fast that we can't really detect it. Uh.
You may have noticed, you know, lightbulbs that for us,
and bulbs that flicker like even when they're on, they're
just they're just flickering. And that's only speaking. That's the
ballast that is trying to control this. And you're talking
about alternating currents, the currents running essentially one way and
(39:08):
then another way, so it's doing it, you know, and
the ballast is working for both directions of current and UH,
and some of the older bulbs the system was not
controlled very well, like they might have used a magnetic ballast,
which has a slightly slower reaction time than current ballasts
(39:28):
that are UH that are usually based on circuitry. So
those older ballasts, you know, it meant that if you
had a fluorescent bulb turned on, it might give you
that flickering look and you might feel like your workplace
is the same one that was in the documentary Joe
Versus the Volcano, And you think you have a brain cloud.
That's right, you have a brain cloud. Well, then you
(39:49):
have to go to this volcano UH and encounter three
different versions of the same actress. And I was I
was working on a Joe about how when you were
flying in your hot air balloon and you needed to
go higher, you would throw out the fluorescent light fixtures
because you know the kind of throw the ballast's overboard.
Ironically enough, that's somewhat true. I've changed a ballast out
(40:12):
of my fluorescent light fixture in my kitchen and they're heavy,
are they It's like a brick. Anyway, Well, we should
probably move on to the third type of light bulb.
I wanted to talk about the LED. Actually, if you
look at our artist believe it or not, there's an
article on how stuff works dot com about light emitting diodes. Yeah,
we have articles on all of this which made this
podcast way easy to research. Yes, yes, But the funny
(40:37):
thing is if you look at the diagram, the the
cross section that are artists have put together of a
light emitting diode, it's sort of in a way resembles
an incandescent light bulb because it is a diode inside
a casing. Yeah, now in this case, the the light
of Right, the light emitting diode is a is a
type of semiconductor. Actually, in a way, it's the simplest
(40:59):
se conductor. There is a diode in general, not just
a light emitting diode, but a diode in general is
a semiconductor, and it conducts electricity, but not as completely
as it could. Right. Essentially, it's a semiconductor. It has
a varying ability to conduct electricity, so sometimes it connect
like an insulator, sometimes as a conductor. It all depends
on this stuff. Generally speaking, control what what you have
(41:25):
is you've got a semiconductor with two different types of material,
and it tends to we tend to call it N
type material and P type material. So the N type
material has extra negatively charged particles, so it has a
negative charge overall. Then the P type material, I think
you can see where this is going, has extra positively
(41:47):
charged particles. Yes I'm positive, not just sure, I'm positive.
So you can think of the N type material as
having an excess of electrons. The P type material has
what we call holes. These are places where the electrons
could go. Now, electrons definitely want to get over to
(42:09):
the positively charged holes. They want to move to those
holes because, as we know, when you're talking about charges,
opposites tracked. John Marsha, Yes, in in subatomic particle form.
So you've got the negative and the positive materials and
they're kind of smushed together in a in a diode.
(42:29):
So you've you've bond together the IN type material to
the P type material. So you've got the the negatively
charged and the positively charged m botted together. And there's
an electrode attached to each end. So the N type
has an electrode attached, the P type has an electrode attached. Now,
if you don't apply any voltage across this diode. The
(42:50):
electrons from the N type material fill up the holes
in the P type material, and it creates what is
called a depletion zone. And in the depletion zone, the
semiconductor becomes an insulator. You know, you've you've got those
extra electrons, have filled up the holes that were on
the positively charge side, and you've reached sort of a
(43:11):
neutral ground, right, So depletion zone is that neutral ground.
There are no free electrons or empty spaces, so it's
just kind of there. But if you want to get
rid of that depletion zone, then you need to push
electrons across, moving from the N type area towards the
P type area. And then h to do that, you
(43:34):
just connect the the IN type side of the diode
to the negative end of a circuit, P type side
to the positive end, and the free electrons and the
N type material are repelled by the negative side because
again you know, like charge repels like yes, they're drawn
to the positive end, and you then complete the circuit
and you get this um you get this electron movement.
(43:57):
If you try to go the other way, it wouldn't
work because the negatively charged particles going into the positive
end would just fill up the holes and then it
would stop. So a diode is kind of like a
one way street and electronics, if you hook up a
diode U current can only flow in one direction and
it will not flow the other way. So if you
even if you reversed the current, it would not complete
(44:21):
the circuit if it went against the diode. Reversing the
polarity just won't work, Captain. So that's your basic led.
But visible light emitting diode are made up of materials
that create a wide gap between where the hole is
(44:43):
and where the electrons are so that when the electrons
move through they do emit they give off photons. Because
again we're talking about when electrons are moving down through
the orbitals. Uh you know, you you've given them enough
energy for them to to move out of their normal orbitals.
Once they move down, they get off light. Well, the
greater that gap is, the more light they give off.
(45:04):
So if you create a visible light emitting diode and
you use these materials that create these wider gaps between
the conduction band and the lower orbitals of the electrons,
that gap is what allows the electrons to give off
light and in general, these L E d s tend
to look if you look at a single LED, they
(45:27):
tend to look like a miniature light bulb light Christmas saying,
now there's no filament in there, because again you're just
what all you're doing is you're allowing those electrons to
move in those those orbitals, and that's what's giving off
the photons. And these little light bulbs tend to be
shaped in such a way that it guides the light
that's emitted in a very particular direction. So that way
(45:49):
it's a very concentrated light. Yes, So if you see
an LED light fixture and this could be you know,
an LED light bulb or on on the back of cars.
I've seen a lot of um uh tail lights in
recent cars that use L E d s, And you
can tell because it will be a group of them
together um. And so it looks like there are lots
(46:10):
of little tiny dots of light in a pattern you know,
maybe a UM series of concentric circle type things or
or you know, some other kind of thing um and
it's you can you can tell that it's an LED
light specifically because you can see the little dots but
together when they work together like that, they can be
very bright. I have a couple of LED flashlights as
(46:31):
a matter of fact, Um that you know. You's like,
hey does this thing work? Oh? You know, Um, however
they're very efficient. Yes, yes, I've got a couple of
LED lights in my house. Actually, there are a couple
of light fixtures that were specifically designed to work with
LED lights. And yes, they are incredibly efficient, particularly compared
(46:52):
to incandescence and even fluorescence. But we didn't really mention
it before. Escent lights are more efficient than incandescent light bulbs. Yes,
they last longer, they use less energy to create light.
They don't They don't lose as much energy in producing heat.
So yeah, so they don't heat up as hot as
an incandescent bulb. That's not saying that a florescent bulb
(47:12):
is going to be cool to the touch. It's just
not going to be as hot as an incandescent bulb.
Is l E ED is even more efficient. Uh, it
has a much higher luminous efficacy, if you will. As
we say in our article on L E D s,
what's your language? I'm sorry, um, but they talked about
how in our article they mentioned a specific type of
(47:34):
LED light bulb in this case, it was this Sewel's
Evo lux LED bulb, which produces seventy six point nine
lumens per what, which is essentially how bright. This is
dependent upon how much energy you're putting into it, whereas
an incandescent bulb is seventeen lumens per what. So seventy
six point nine versus seventeen it shows that the efficiency
(47:58):
of the l e ED is far greater than that
of the incandescent bulb, and the LED lifetime can be
around fifty thousand hours, So compare that to a couple
of thousand hours for a typical incandescent bulb, and that's
a big difference. Now, LED light bulbs do tend to
(48:19):
be much more expensive than incandescent or fluorescent bulbs. However,
if you measure that across the lifetime of the bulb
and you factor in things like energy savings, uh, they
on the long term can be a good investment. However,
the upfront cost is still much higher, so that can
be a barrier for a lot of people. The cost
(48:40):
has been decreasing UH quite a bit since over the
last decade or so, since semiconductor material has become much
more cost effective. Is when these first came out, semiconductor
material was a precious commodity. It was not something that
was mass produced. It was not something that you could
easily get your hand ends on, and so it was
(49:01):
much more expensive. But just as Gordon More predicted way
back in the sixties, the manufacturing processes would mean that
costs would come down, efficiencies go up, and as a result,
we're able to get more efficient products. Now he was
talking specifically about integrated circuits, but as it turns out,
that kind of applies to lots of stuff. Doesn't necessarily
(49:22):
mean that the light bulbs will have next year will
be twice as bright as the ones we have this year.
So the analogy doesn't continue all the way there, but
it's still I think, semi applicable. So yeah, you can
see the differences between these these approaches. Uh, Ultimately, it's
all about again exciting atoms, and once those aboms get excited,
(49:45):
they just light up. I hope you guys enjoyed that
classic episode of tech stuff. I really liked when we
got to do the history ones where we got to
really dive into what actually happened, because frequently the stories
that we learn in history books are the fast, simple,
easy explanations, because as we really begin to understand the
(50:07):
more we look into technology, development of new technologies is
often very complicated, with lots of different people making contributions
that ultimately will result in a new technology kind of
coming to be. But it's rarely so simple as to
point to a single person and say, that person right
(50:29):
there did it. Yo. If you guys have suggestions for
our future episodes of tech Stuff, reach out to me,
send me a message on tech stuff at how stuff
works dot com, or pop on over to our website
that's tech stuff podcast dot com. They're going to find
an archive of all of our past episodes. You'll find
links to our social media accounts, and you will also
(50:50):
find a link to our online store, where every purchase
you make goes to help the show. We greatly appreciate it. Now,
I'll talk to you again really soon. M Text Stuff
is a production of I Heart Radio's How Stuff Works.
For more podcasts from I heart Radio, visit the i
heart Radio app, Apple Podcasts, or wherever you listen to
(51:12):
your favorite shows.
Welcome to tex Stuff, a production of I Heart Radios,
How Stuff Works. Hey there, in Welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
How Stuff Works and I heart Radio and a love
of all things tech, and it is time for a
classic episode of tech Stuff. This episode is one I
(00:26):
referenced in a very recent episode of tech Stuff. In fact,
it maybe so recent that I don't know if it's
published yet or not. It's called tex Stuff Gets a
Bright Idea, and it's all about the real history of
the light bulb. We often hear that Thomas Edison invented
the light bulb, but did he for real z s though?
(00:47):
We find out in this episode. Hey there, I just
looked up and there he was doing that thing, getting
my get my energy up. Actually, one of the things
that uh, you know, we start the episode of pretty traditionally,
one of the things that we had as an early
ritual as we recorded Tech Stuff was Jonathan and I
would be sitting here in the virtual darkness and someone
(01:10):
we had different engineers over the time over the years now,
but someone would come in and turn on the lights, yes,
and usually lighted begs, but we wanted to talk a
little bit about light, specifically light bulbs today. So what
a brilliant idea of those were? You know before lightbulbs,
Before light bulbs, there was no way to indicate that
(01:32):
you had an idea. Yeah, yeah, there's no there's no yeah,
pre light bulb there was no ting. Before we get
into how lightbulbs work in their history and everything, I
want to lay down a little physics for you. All right,
go ahead and enlighten us. See what you did much?
(01:52):
So we are talking about light and what is light? Well,
light is made up of these very tiny part of
all like packets called photons. They've got energy, they have momentum,
but there's one thing they do not have charge accounts
mass or I was going they have no mass, but
(02:16):
not no moss. Photons are these packets of energy. They
have momentum but not mass. And these particles, these these
photons are emitted by atoms. Once you have excited an
atom to the point where it's electron starts to move
out of its normal orbit and goes into a further
(02:39):
orbit from the atoms nucleus. And once once you remove
the energy source from that atom, the electron will eventually
return to its normal orbit around the nucleus. But it
has to it has to get rid of that energy
that you have pushed into it. Right, energy is not
created or destroyed, it's just transferred. So this electron, as
(03:02):
it's coming back down to its normal orbital is going
to shed off energy. And in this case, the energy
is in the form of photons. Now, photons are going
to be emitted in the entire spectrum of light. Now, humans,
we are capable of perceiving a narrow band of that
spectrum called the visible spectrum because it's visible to us. Oh,
(03:28):
I always wondered about that. This is where the whole
roy G BIV thing comes in. Right. The different wavelengths
of light dictate what the color is as we perceive it. Uh.
The but the the light goes well beyond outside the
the visible range. There's things like ultra violet and infrared,
and then you get into electromagnetic radiation as you go
further out. But and anyway, Uh, these photons can come
(03:52):
into various forms, so you can have of infrared photon
or ultra violet photons. So, uh, if it's in the
visible light spectrum, we're able to see it. Now that's
important because that's the whole basis of creating a light bulb,
as you want to create some sort of device that
(04:13):
you can use to create photons so that you can
illuminate an area, and before light bulbs, you didn't really
have that option unless you set something on fire. Uh,
And there's a limited number of things we can set
on fire before we set ourselves on fire or we
run out of stuff that is flammable. So it was
a good idea to try and develop something that could
(04:35):
create light in another way. Now, Uh, how do we
know about how what is the principle upon which light
bulbs work. Well, again, if you excite an atom and
you push those electrons out, when the electrons come back in,
they emit photons. If you give enough energy to an object,
(04:59):
then you can it enough uh photons for it to
be within the depending upon the nature of that material,
for it to be within the visible spectrum for it
to be perceptible. Because even if it's in the visible spectrum,
if the energy is not great enough, you won't be
able to see it. And we're all emitting energy all
(05:19):
the time, like humans are emitting infrared energy all the time,
and if you had an infrared camera, you would be
able to see it even in a perfectly dark room.
You look at the infrared camera, look at a person,
you would see light as interpreted by the sensor in
that camera and converted to visible light for us to see.
You would be able to see that person because they're
emitting that infrared light. Well, we may even depending on
(05:42):
what what, depending on the material, it may even be
emitting visible light, but it might be emitting at at
levels so low as to be imperceptible to humans. So
if you add more energy, you can boost that and
actually see the visible light. Uh. And this can happen
with things like soled materials. And there was a fellow
named John William Draper who in seven demonstrated that solid materials,
(06:09):
almost all of them, will glow once they reach a
temperature of seven kelvin. Kelvin's a scientific scale for temperatures.
Kelvin is what we have when you get to zero
kelvin that says that's as cold as you can get.
It actually refers to molecular movement, and at zero kelvin,
(06:30):
there is no molecular movement. So that's like the deepest
depths of space. Where there's nothing absolutely absolutely uh So,
if you wanted to convert that into degrees that we're
more familiar with most of us anyway, it would be
about five and twenty five degrees celsius or nine seventy
seven degrees fahrenheit. And at that temperature, solid materials will
(06:54):
start to glow. We call it the draper point. Now,
in order to have a object glow at a uh
at a at an intensity bright enough for it to illuminate, say,
a room, you will have to put in more energy
than that, right, because this is talking about they start
to glow, but that doesn't mean that they're glowing so
brightly as to illuminate an entire room. That's where it starts.
(07:17):
So but you know, you've you've probably seen this. If
you've ever seen a blacksmith work, then you know the
blacksmith might be heating up iron and when they take
that out it's glowing red. Or a glass blower or lava.
You know, there's lots of stuff that tends to lava.
It's not all man made, but there's lots of stuff
out there that um that that demonstrates this. So that's
(07:42):
the principle. But but the idea behind an electric light
source actually predates Draper's discovery. Really, yes, back in well
the early eighteen hundreds. I've seen I've seen reports from
eighteen o six all the way up to eighteen o nine.
There's some discrepance's there. But an English chemist and inventor
(08:03):
named Sir Humphrey Davy, named Humphrey Davy, he was designated
a night So that's the sir. He connected a battery
to a strip of charcoal and he used the electricity
to actually heat up the charcoal to the point where
it started to glow, which created technically the first electric
(08:24):
arc lamp. Uh. This was not a viable means of
illumination as it was hard to do. It required a
lot of energy. The battery drained really quickly, the carbon
burned at such a or it got so hot as
to be incredibly dangerous for uh, say, I don't know
(08:47):
a typical house. Um. So it was not something that
was going to immediately be adopted into every household, but
it was proving a concept. Uh. Also, by the way,
sir very Davy did go on to invent many things,
including the Davy lamp, which was not an electrical lamp.
It was a gas lamp. There was a gas lamp
(09:08):
that had a mesh screen that would surround the flame,
so that miners meaning people who mind the earth, not
people who are underage miners, could take the lamps, although
depending in England at that point in the time, the
two may have been the same. Hey, our history has
not always been a nice one. But the miners could
(09:30):
take a lamp down below the ground and even if
they encountered a pocket of gas, the mesh would actually,
this fine mesh would prevent the gas and the flame
from making friends and becoming a big boom. Very important
for miners of both types. So the he did invent that. Again,
(09:51):
not electrical, but I thought it was an interesting aside.
Moving ahead back in one Frederick de Moulins, and I'm
sure I have completely mispronounced his name, and I apologized
profusely for that. Another Englishman, Yeah it could be. He
patented a lightbulb in eighteen forty one, and this one
(10:12):
was comprised of a glass case and a burner or
burners actually made of carbon and in expensive material you
may know as platinum. Yeah, you thought that led light
bulbs were expensive, so uh he he patented that design
again not really practical for for every day or even
(10:34):
industrial use. An American inventor named J. W. Starr received
a patent for a light bulb that used a carbon burner. UM.
And then the next few decades were spent among inventors
trying to find a way to perfect the discoveries these
earlier inventors had found, so that you could create a
(10:55):
light bulb that made sense, that that was a ficient
that could light well, that was not going to be
prohibitively expensive. And there are two names in particular that
pop up all the time, one of them being probably
the most famous, uh connected to the light bulb, which
is Thomas Edison. Yes, it's funny. As we were recording this,
(11:18):
we are rapidly approaching the hundred thirty third anniversary of
the first test of Edison's incandescent light bulb. Yeah. Now,
it is important to note Edison was not the person
who invented the light bulb. He was not even the
person to invent the incandescent light bulb, but he was
someone who perfected that design and made it viable as
(11:39):
an actual product. Yeah. Now it's it's important to know,
um that these these early light bulbs. Uh, you know,
not only were homes not really wired. Actually, the light bulb,
I would argue, based on my research the over the past,
you know, the past times that we've done tech stuff.
We've talked about Edison and Tesla and all these the
(12:00):
lightbulb actually was sort of the key to getting homes
wired for electricity. Yeah, I mean you and it made
sense because suddenly you had households that could be uh
safely with air quotes around that lit after dark and
extend the useful uh time human being could get stuff
(12:22):
done because otherwise, when night fell, we might as well
just go to bed because it was gonna be pretty dark. Well,
you know, we're related bed and early to rise, as
they say, early to bed, early to rise, because otherwise
you're barking your ship on the coffee table. Well, yeah,
that's that's true. Well, gas lamps, uh were very very popular.
(12:43):
But they were I mean, in addition to being obviously
inherently somewhat dangerous um and oil lamps, but they were
um smoky, um. They were dirty. So you know, I'm
sure they probably didn't smell all that great um. But
the problem with these early lightbulbs is that they weren't
(13:04):
very practical. Okay, look, I got Yeah. There was another inventor,
an Englishman, the Englishman named Sir Joseph Swan who was
working on light bulbs around the same time as Edison,
and Swan's bulb used carbonized paper as the burner, which
worked pretty well except that it didn't last terribly long.
(13:25):
And in fact, this was a problem that a lot
of lightbulb researchers were encountering that including Edison. The first
problem was, all right, well, we've we've found uh that
if you if you run enough electricity through some sort
of object, you can heat it up enough so that
it begins to glow. But if that item is exposed
(13:49):
to oxygen, then it will burn. So even if you
found a material that does not melt at a high temperature,
it would burn, It would combust at a high enough
temperature because it, you know, it would be adjacent to oxygen,
which you know that that's part of the fuel you need,
you know, in order to have a fire. UM. So
(14:09):
the you had to close it off from oxygen, which
is why there were these these vacuum tubes essentially is
what they create, these vacuum containers. UM. But Once they
got through that, they had to find what's the right
material to use. Actually, what Edison ended up using at
first was bamboo. He took Japanese bamboo and carbonized it
(14:34):
and created a filament. And in this case, what a
filament is is this really long, long, long, long strip
of material that is then coiled so that you can
decrease the space that it needs to um to fit
into whatever you want to put it in. So it's
got a lot of surface areas. Then the resistance is high.
(14:56):
A resistance in electricity is the the materials resistance to
electrons flowing through it freely. The more resistance there is
in general, okay, you've got greater resistance, you have greater heat. Well,
the secret to the light here is the amount of
heat that's being generated. That's the energy that is creating
this whole system of electrons being pushed out and then
(15:17):
when they start coming back in, the photons are being
let out. So let the photons out? Who let the
photons out? That was as an a swan as it
turns out. Um. It's interesting because then Edison Edison ended
up hiring what his first his first light bulb design
used a temperature controlled switch to try and keep the
(15:40):
material at the right temperature so that it would the
light bulb would remain lit longer, because I was an
early problem with these light bulbs is that their their
utility was low because they couldn't couldn't burn them for
very long. But this was a problem because the the
temperature control controlled switch, once a certain temperature was hit,
it switch off right the light would go off, And
(16:03):
so I started creating this flickering problem and made the
bulb practically unusable. So he then hired a physicist from
Princeton named Francis Upton, who led Edison's research team working
on light bulbs, to start practicing with other stuff. That's
when they came upon the idea of using the bamboo
as a filament. Um. Swan and Edison ended up battling
(16:27):
each other. Edison ended up taking patent lawsuits against Swan,
but then ultimately the two of them formed a partnership
together and they created the Edison Swan United Company. Teamwork teamwork. Um. Yeah,
just so, just so you guys know, patent wars are
not a new thing. Oh no, not in the least. Um. Yeah,
(16:49):
it's funny. While while carbonized bamboo sounds like an ingredient
for a hipster sandwich. Um, it did have the ability
to burn for more than which you know back in
that time, that was pretty nice for a for a
light bulb. Yeah, and uh, this served as the basis
(17:10):
for what future light bulbs would be and then we
ended up shifting to a different type of filament. But
we'll get into that in a second. So let's talk
about the basic anatomy of an incandescent light bulb. And
don't worry florests and an l e defense. We're going
to get to you too. You just sit tight. So
the incandescent bulb, you've got two contacts to two electrical
(17:35):
context on this on a typical incandescent bulb. One of
them is at the very end of the bulb, that's
the base of the bulb, and the other is in
the actual treads that you screw into your um light
bulb sucket. Yeah. Actually usually has a squeaky noise which
has that perfect pitch to give me the heb gbs.
(17:59):
It's like the finger nae else on the chalkboard type thing.
It's like almost every single light bulb in my house
makes that noise. And so it's a physically demanding task
for me because well, I guess psychologically really more than physically,
because I I suffer trauma. One follows the other. You
start to how many how many Jonathans does it take
(18:20):
to you screw the light bulb? Well, after the first one,
it takes a few others to calm them down. Yeah,
I'm not afraid of the dark. I'm just afraid of
changing light bulbs. So that's not really true. I just
don't like doing it. But anyway, these metal contacts are
what create the the circuit, right, so that the circuits
complete when these two contacts are are in contact with
(18:44):
the rest of the electrical system. To one um, the
contacts are attached to some wires and those wires are
attached to the filament. Now, in this case, the filament
is no longer bamboo. For your typical incandescent, it's usually tungsten.
And the reason why it's tungsten is a couple of
(19:05):
different reasons. One is that the melting temperature of tungsten
is really high, so you can heat tungsten up quite
a bit and not worry about it being um melting
away that that that's obviously another issue with light bulbs. Right,
you heat up materials, some material is gonna melt, and
it might melt before you hit that draper point, which
(19:25):
would be bad because you wouldn't get any light out
of it. You would just get a you know, a
glass cylinder of hot molten sludge. Um hot molten sludge
would be a great name for a band. It is.
It is, however, very thin. The filament is very thin,
as anyone who has uh smacked a light bulb hard
(19:46):
enough to break the filament but not hard enough to
break the glass knows that's really annoying. That's another really
annoying thing about changing light bulbs. Oh man did I Yeah,
just ruined it perfectly good by bulbs. So yeah, it's
very thin again, that's to increase resistance. That's another thing.
Is that a a a copper wire, for example, the
(20:10):
the greater the diameter of a copper wire, the lower
the resistance. So if you have a very um thin
copper wire, the resistance is greater. That means it's going
to also generate more heat as a result. Well, this tungsten,
same thing. I mean, this same principle applies across all materials.
Tungsten filament is very very very thin. It's actually coiled twice.
(20:33):
The first coil is done to decrease it's you know,
the length, and then after you've coiled it once, you
coil it a second time around. Uh. These these support
wires and UH that helps when the tungsten heats up,
it starts to generate, you know, give off these photons. Uh.
(20:53):
It helps, uh concentrate that light so that you have
enough for it to be useful. Because again, you want
to give enough energy there for you to have visible
light that you can actually see stuff by, but you
don't want to have to pour in more energy than
was necessary. And we should point out incandescent bulbs not
terribly efficient. No, we think about heat being a a
(21:15):
wasted form of energy in this case, and how hot
and incandescent bulb gets. And it's also giving out photons
outside the range of visible light, so you're getting you know,
infrared light and maybe even ultraviolet light from from these
light bulbs. Well that that means that again it's a
drop in efficiency. I mean, yeah, it's giving off light,
(21:36):
but we can't see it, so it doesn't do us
any good, not not in a normal application. Anyway, you know,
if you're doing something that required infrared or ultraviolet light,
than sure, although there are better ways of doing that
than using a regular incandescent light bulb. I mean you
you could you could even cook brownies with it, which
is with an easy bake oven. It's funny because I
(21:58):
don't think people not everyone realizes this. It's not like
a secret. But um, the the older easy bake ovens, especially,
they're they're essentially using the heat from a lightbulb to
cook uh, you know, very simple cakes and brownies and
things like that. Right now, the you know, you might
ask what's inside a lightbulb? Besides all this stuff, there's
(22:20):
actually a gas that's inside most incandescent light bulbs, and
it's usually are gone, which is an uh it's an
inert gas, meaning it does not react to other stuff. Hey,
are gone gas. That's a tornado outside. Yeah, So like, oh,
you never do anything now that you want it to
be inert because obviously, like something like oxygen, then the
(22:41):
tungsten would start to burn. It would dramatically decrease the
life lifespan of your average light bulb. So they pump
the oxygen, they pump air out of the glass. Globe
and fill it with are gone gas. Yep. And so
you might say, well, why why not just have a
vacu mist of argon gas. The reason for that is that, uh,
(23:04):
at that high temperature, you have another problem besides combustion,
even if you don't have auction, the other problem is evaporation.
Atoms from the tungsten will actually evaporate off the filament
because of those high temperatures, and over time that means
that you're losing you know, every time you're using that
light bulb, you're losing tungsten. With the old light bulb, Yeah,
(23:25):
and with the old light bulbs, you would actually have
the tungsten start to evaporate away and coat the inside
of the light bulbs, So the light bulb would get
more and more dim both because there was less filament
to light and because all the filament that was gone
is now coating the inside of the light bulb making
it darker. So by using argon, what it actually acts
(23:46):
as a sort of a sort of a barrier. These
atoms from tungsten will come off the filament, bump into
a an argon atom, and then because argon's a nerd,
it's not going to act with that. That um energy,
or that that particle rather the particle then returns to
(24:07):
the strip of tungsten um. So it acts as kind
of a cushion. It's just pushing the the atoms back
to the tungsten. Keeping that filament last to last longer
very important. And so that's the basic premise behind these
incandescent bulbs. They you know, they get to a pretty
(24:29):
hot temperature. We're talking around degrees celsius or four thousand
degrees fahrenheit um. Because again, you want to put out
enough visible light for it to be useful. Now that
all depends on the wattage of the bulb. Yeah, which
generally speaking, you can think of his brightness, um, it's
(24:49):
it's kind of or or really you can think of
his brightness or how hot that tungsten's getting inside the
light bulb. That's what that kind of translates into. Uh
and UH interesting. We have an article on the site
how light Bulbs Work and how stuff Works dot com.
Great article, great illustrations, a fun read. I mean, I
(25:11):
really do think that it's actually you would think it's
an article about light bulbs, but it really is a
fun read. And one of my favorite UH facts in
this is that a typical sixty what bulb has a
tongusten filament that is six and a half feet or
two meters long and one hundred of an inch thick.
(25:31):
I don't have the centimeters for that, sorry, but it's
you know, six and a half feet long or two
meters And if you were to completely uncoil that filament, however,
once it's all double coiled, it's in a space that's
shorter than you know, the tip of your pinkie finger,
and you're thinking, wow, that's to go from six and
(25:53):
a half feet to that is pretty impressive, you know.
And again that's packing all that material and so it
can give off enough light for it to be useful.
I just got my own bright idea, which means a
light bulb just went off over my head. And that
idea is, will now take a quick break, do you uh?
(26:19):
If you happen to know how three way light bulbs work.
I do not. Actually, as a matter of fact, we
have another very very short article on how three way
light bulbs work, and they also have two filaments. Um,
it's it's very interesting. Now the socket has to accommodate
that because it has to do also with a connection
(26:40):
on the outside. But essentially what happens is that the
socket is, you know, through a switch, providing instructions on
which of the two filaments to light. So for the
first on switch, if you ever use a three way light,
you know that the first one is the lowest setting
uses the least amount of electricity. Well, the one filament
that is designed for that lower setting comes on when
(27:03):
you click the switch. Again, that provides instructions for the
second filament, but only the second filament to come on,
and then the third the two team up. I see,
So that and then that the off got you. You
get these the sum total of light coming from the bulb,
which is, if you'll pardon upon a brilliant way to
do that because it's very simple, shiny. So moving on.
(27:25):
That's a little just aside and firefly reference for you
guys out there. And of course you can achieve different
effects to what the kind of glass you might be wondering,
you know what the natural lighting or the what does
the blue what's the blue one do? Well, it's it's
just diffusing the uh photons given off by the tungusten
inside the light bulb a little bit different and I
(27:47):
should point out a neat that depending upon the material
you're using, that will determine what kind of light is
given off. Right, So tungsten's giving off this light, uh,
partially because of the fact that it's tungsten. But other
materi areals give off different kinds of light, different colors
of light along or or essentially lights that are different wavelengths, right,
(28:08):
so different parts of the spectrum, sometimes visible, sometimes not. Uh.
This is used in chemistry, it's used in astronomy, it's
used in lots of different areas of physics, not just
in creating light bulbs or you know, heating stuff up
until it glows. But that kind of that's kind of
the full discussion on incandescent bulbs. But those aren't the
(28:28):
only kind of bulbs we have. We also have fluorescent bulbs. Yes. Um,
you might say, well, you know, uh, Edison and later
the company that he was directly slash indirectly the founder
of General Electric, you know, perfected the the incandescent light
bulb and uh uh you know you would think that
(28:50):
they would be very upset that the fluorescent came out.
Well not really, because, as we touched on on our
famous or infamous GE series How How Influence Famous? That's
more than the series on G E G. E was
actually in development of the fluorescent light bulb. Yeah, so
fluorescent lightbulbs use a different method of generating light, so
(29:14):
you're not you don't have that physical filament inside a
fluorescent bulb. Instead, what you have is a sealed glass tube.
By the way, we also have how fluorescent lamps work
at how stuff Works dot com. So again you should
read that if you're interested to learn all the physics
involved in this. But in general, you've got a sealed
(29:34):
glass tube and not the animal that Chris was alluding
to earlier. It's just completely sealed. Uh. The tube has
inside it's some mercury and there's also an inert gas
like again are gone. Uh. The inside of this glass
tube is coated with a powder that's phosphorus. Now, phosphorus
(29:57):
means that when light stri exit, it gives off light.
So that sounds like it could be totally useless, except
we're talking about light within the entire spectrum. So even
if if you have a certain kind of phosphor, it
will um if you were to hit that phosphor with
(30:19):
light that's outside the visible spectrum. For example, ultraviolet light,
and then that phosphor actually emits visible light. That becomes
useful because you can either look at stuff that is
in the presence of light that's otherwise outside our our
field of vision, or you can create something like a
fluorescent light bulb that uses light outside of our vision
(30:43):
to create light that's inside our vision. The way this
works is you've got the electrodes at either end of
this tube that are wired to some sort of circuit. Now,
the circuit, once we turn that on, starts to introduce uh,
free flowing electrons into the gas. Now this is different
from the filament approach because then you have electrons running
(31:06):
through a material directly right, just like you would a
wire in a circuit. I mean, that's essentially what it
is with this. It's free flowing electrons going through uh.
The gas in this case AREGNE. It takes a little
while for these electrons to be introduced into this this tube,
which is why when you turn on most fluorescent light
(31:27):
bulbs there's this little flickering moment while it's coming on. Ye.
The cause, again, the the has to introduce the the
free flowing electrons for this to work. So once these
electrons with considerable voltage are introduced. UH, the energy starts
to change some of the mercury that's in that tube
(31:50):
from liquid to gas. Now, again, when we're introducing electricity
into or energy into an atom, it's exciting those electrons,
pushing them out of their orbitals. UH. And then when
the electrons start to come back down to their normal
orbital they'll give off photons. With the case of mercury,
(32:10):
you're talking about light photons that are in the ultra
violet wavelength range. So again you can you are exciting
the mercury and it's giving off ultra violet light. We
can't see ultraviolet light unaided anyway, we're incapable of seeing
light at that wavelength. But by coding the inside of
(32:30):
that tube with phosphors that are able to absorb ultra
violet light and then emit light in the visible spectrum,
we can use that ultraviolet light two give us light
we can see indirectly. We have this intermediary step with
the phosphors. So the mercury starts to go from liquid
(32:51):
to gas, gives off these ultraviolet photons. The ultraviolet photons
hit the phosphors. The phosphors absorbed the ultra violet light
and emit light in the visible spectrum, and voila or
viola if you prefer, we have ourselves a fluorescent light bulb.
By the way, if you have a black light, you
essentially have a fluorescent bulb that does not have those
phosphors necessarily on the inside, because it's just emitting the
(33:16):
ultra violet light directly. And then you can have those
wicked uh van posters light up in pretty colors. All
in all, you're just another brick in the wall, thank you.
So uh yeah, I mean that's the that's the essential
way that fluorescence work. And this is also why because
(33:36):
they contain mercury why they are so dangerous or potentially dangerous,
because mercury is toxic, and if you were to say,
I don't know, drop a palette of fluorescent light bulbs
in a warehouse, you could have a potentially dangerous situation
on your hands because you could know very much have
(33:58):
enough mercury there to suffer mercury poisoning. Yeah, it's um.
It's in a way sort of amusing that so many
of my friends remember busting fluorescent lightbulbs uh fondly because
they make out, they make a loud noise. I had one.
I was in a bookstore once when uh, and I
(34:19):
was just perusing some books, so I'm very much focused
on what I'm doing when the employee behind me, who
was trying to change out a fluorescent bulb, accidentally dropped
the one in her hands from a ladder and it
landed directly behind me. And I thought I had just
been hit by a shotgun. Okay, turned out I wasn't
(34:40):
well and and and at that time, it wasn't uh
popular knowledge. I probably shouldn't say common knowledge, but popular knowledge.
People just didn't know, uh, that there was mercury in there. Now,
I mean, admittedly there's not a boatload of mercury in there,
but you know, it could it could be something serious.
And that's why in your fluorescent light spurned out, it's
(35:02):
a good idea to find someone who can take it
and recycle that, not only for safety reasons, but also
because you know they can recover some of that material. Now,
when you're talking about the fluorescent light tubes, UH, that's
pretty much it. I mean you've got the uh, the
tube of gas with the caps on the end, and
you plug it into the uh the light fixture to
(35:24):
have it work. Well, there's there's other stuff underneath that
that you may not necessarily see. It's it's covered up
by the fixture. UM. One of the most important parts,
I would argue is the ballast, which is a type
of transformer UM that basically ups the electricity to make
it work better with the fluorescent light, because again, you
(35:46):
have to introduce those ions, which is not necessarily easy
to do, especially since you've gotten a neert gas in there.
We're gonna take another quick break here in a second,
and then after we come back, Chris and I will
shine a little more light on this subject. So if
(36:08):
you ever looked at a compact fluorescent line or curly bulbs,
I like to call them UM because I like to
do that UM and wonder what the heck the big
honking bases that you have to screw into a regular
light fixture. That's where the ballast is. The ballast is
built into the base of that UH, that fixture, UM,
(36:31):
which is why it may or may not fit into
that incandescent and that that fixture that you bought that
would allow you to use a UM a typical incandescent bulb.
Now they say in some cases that you should not
use those because they do generate heat and that can
uh make the ballast overheat, uh, cause a short circuit
(36:52):
and possibly fire. You know, it depends on what kind
of fixture you have, so keep an eye on that.
But if you've wondered what that what that situation is, um,
it's built into the ballast, and the ballast is also
in that case what controls the three way There are
some three way fluorescent compact fluorescent whites. Um. The ballast
is what makes that possible because it can control the
(37:15):
amount of electricity going into the tube. Yeah, it's also
important to point out that another big difference between using
free electrons moving through a gas. Essentially you're talking about
ionized gas or plasma. But I know if you're using
free electrons moving through a gas, it does behave differently
than it would if those electrons were moving through a wire. Uh.
(37:39):
Now with a wire, you know you have the resistance
is dependent upon the composition and the size of the wire.
In a in gas discharge, which is in the terms
of this not something that's gross is uh, it's the
resistance actually decreases due to current. So when you've got
(38:01):
a current going, the resistance begins to decrease through this
gas that's more electrons and ions start to flow through.
They bump into more atoms, free up more electrons, creates
more charged particles. So the resistance is UH is constantly
decreasing as long as that currents on, and that can
be a problem. If that continues for too long, it'll
(38:23):
blow out the electrical components of the the the entire system.
So that's another reason why these ballasts are important. They
are little safety features that control that so that the
current doesn't continue indefinitely. It stops briefly, but not so
briefly as to make the lightbulb turn off, or at
(38:46):
least if it's turning off, it's turning off at a
rate so fast that we can't really detect it. Uh.
You may have noticed, you know, lightbulbs that for us,
and bulbs that flicker like even when they're on, they're
just they're just flickering. And that's only speaking. That's the
ballast that is trying to control this. And you're talking
about alternating currents, the currents running essentially one way and
(39:08):
then another way, so it's doing it, you know, and
the ballast is working for both directions of current and UH,
and some of the older bulbs the system was not
controlled very well, like they might have used a magnetic ballast,
which has a slightly slower reaction time than current ballasts
(39:28):
that are UH that are usually based on circuitry. So
those older ballasts, you know, it meant that if you
had a fluorescent bulb turned on, it might give you
that flickering look and you might feel like your workplace
is the same one that was in the documentary Joe
Versus the Volcano, And you think you have a brain cloud.
That's right, you have a brain cloud. Well, then you
(39:49):
have to go to this volcano UH and encounter three
different versions of the same actress. And I was I
was working on a Joe about how when you were
flying in your hot air balloon and you needed to
go higher, you would throw out the fluorescent light fixtures
because you know the kind of throw the ballast's overboard.
Ironically enough, that's somewhat true. I've changed a ballast out
(40:12):
of my fluorescent light fixture in my kitchen and they're heavy,
are they It's like a brick. Anyway, Well, we should
probably move on to the third type of light bulb.
I wanted to talk about the LED. Actually, if you
look at our artist believe it or not, there's an
article on how stuff works dot com about light emitting diodes. Yeah,
we have articles on all of this which made this
podcast way easy to research. Yes, yes, But the funny
(40:37):
thing is if you look at the diagram, the the
cross section that are artists have put together of a
light emitting diode, it's sort of in a way resembles
an incandescent light bulb because it is a diode inside
a casing. Yeah, now in this case, the the light
of Right, the light emitting diode is a is a
type of semiconductor. Actually, in a way, it's the simplest
(40:59):
se conductor. There is a diode in general, not just
a light emitting diode, but a diode in general is
a semiconductor, and it conducts electricity, but not as completely
as it could. Right. Essentially, it's a semiconductor. It has
a varying ability to conduct electricity, so sometimes it connect
like an insulator, sometimes as a conductor. It all depends
on this stuff. Generally speaking, control what what you have
(41:25):
is you've got a semiconductor with two different types of material,
and it tends to we tend to call it N
type material and P type material. So the N type
material has extra negatively charged particles, so it has a
negative charge overall. Then the P type material, I think
you can see where this is going, has extra positively
(41:47):
charged particles. Yes I'm positive, not just sure, I'm positive.
So you can think of the N type material as
having an excess of electrons. The P type material has
what we call holes. These are places where the electrons
could go. Now, electrons definitely want to get over to
(42:09):
the positively charged holes. They want to move to those
holes because, as we know, when you're talking about charges,
opposites tracked. John Marsha, Yes, in in subatomic particle form.
So you've got the negative and the positive materials and
they're kind of smushed together in a in a diode.
(42:29):
So you've you've bond together the IN type material to
the P type material. So you've got the the negatively
charged and the positively charged m botted together. And there's
an electrode attached to each end. So the N type
has an electrode attached, the P type has an electrode attached. Now,
if you don't apply any voltage across this diode. The
(42:50):
electrons from the N type material fill up the holes
in the P type material, and it creates what is
called a depletion zone. And in the depletion zone, the
semiconductor becomes an insulator. You know, you've you've got those
extra electrons, have filled up the holes that were on
the positively charge side, and you've reached sort of a
(43:11):
neutral ground, right, So depletion zone is that neutral ground.
There are no free electrons or empty spaces, so it's
just kind of there. But if you want to get
rid of that depletion zone, then you need to push
electrons across, moving from the N type area towards the
P type area. And then h to do that, you
(43:34):
just connect the the IN type side of the diode
to the negative end of a circuit, P type side
to the positive end, and the free electrons and the
N type material are repelled by the negative side because
again you know, like charge repels like yes, they're drawn
to the positive end, and you then complete the circuit
and you get this um you get this electron movement.
(43:57):
If you try to go the other way, it wouldn't
work because the negatively charged particles going into the positive
end would just fill up the holes and then it
would stop. So a diode is kind of like a
one way street and electronics, if you hook up a
diode U current can only flow in one direction and
it will not flow the other way. So if you
even if you reversed the current, it would not complete
(44:21):
the circuit if it went against the diode. Reversing the
polarity just won't work, Captain. So that's your basic led.
But visible light emitting diode are made up of materials
that create a wide gap between where the hole is
(44:43):
and where the electrons are so that when the electrons
move through they do emit they give off photons. Because
again we're talking about when electrons are moving down through
the orbitals. Uh you know, you you've given them enough
energy for them to to move out of their normal orbitals.
Once they move down, they get off light. Well, the
greater that gap is, the more light they give off.
(45:04):
So if you create a visible light emitting diode and
you use these materials that create these wider gaps between
the conduction band and the lower orbitals of the electrons,
that gap is what allows the electrons to give off
light and in general, these L E d s tend
to look if you look at a single LED, they
(45:27):
tend to look like a miniature light bulb light Christmas saying,
now there's no filament in there, because again you're just
what all you're doing is you're allowing those electrons to
move in those those orbitals, and that's what's giving off
the photons. And these little light bulbs tend to be
shaped in such a way that it guides the light
that's emitted in a very particular direction. So that way
(45:49):
it's a very concentrated light. Yes, So if you see
an LED light fixture and this could be you know,
an LED light bulb or on on the back of cars.
I've seen a lot of um uh tail lights in
recent cars that use L E d s, And you
can tell because it will be a group of them
together um. And so it looks like there are lots
(46:10):
of little tiny dots of light in a pattern you know,
maybe a UM series of concentric circle type things or
or you know, some other kind of thing um and
it's you can you can tell that it's an LED
light specifically because you can see the little dots but
together when they work together like that, they can be
very bright. I have a couple of LED flashlights as
(46:31):
a matter of fact, Um that you know. You's like,
hey does this thing work? Oh? You know, Um, however
they're very efficient. Yes, yes, I've got a couple of
LED lights in my house. Actually, there are a couple
of light fixtures that were specifically designed to work with
LED lights. And yes, they are incredibly efficient, particularly compared
(46:52):
to incandescence and even fluorescence. But we didn't really mention
it before. Escent lights are more efficient than incandescent light bulbs. Yes,
they last longer, they use less energy to create light.
They don't They don't lose as much energy in producing heat.
So yeah, so they don't heat up as hot as
an incandescent bulb. That's not saying that a florescent bulb
(47:12):
is going to be cool to the touch. It's just
not going to be as hot as an incandescent bulb.
Is l E ED is even more efficient. Uh, it
has a much higher luminous efficacy, if you will. As
we say in our article on L E D s,
what's your language? I'm sorry, um, but they talked about
how in our article they mentioned a specific type of
(47:34):
LED light bulb in this case, it was this Sewel's
Evo lux LED bulb, which produces seventy six point nine
lumens per what, which is essentially how bright. This is
dependent upon how much energy you're putting into it, whereas
an incandescent bulb is seventeen lumens per what. So seventy
six point nine versus seventeen it shows that the efficiency
(47:58):
of the l e ED is far greater than that
of the incandescent bulb, and the LED lifetime can be
around fifty thousand hours, So compare that to a couple
of thousand hours for a typical incandescent bulb, and that's
a big difference. Now, LED light bulbs do tend to
(48:19):
be much more expensive than incandescent or fluorescent bulbs. However,
if you measure that across the lifetime of the bulb
and you factor in things like energy savings, uh, they
on the long term can be a good investment. However,
the upfront cost is still much higher, so that can
be a barrier for a lot of people. The cost
(48:40):
has been decreasing UH quite a bit since over the
last decade or so, since semiconductor material has become much
more cost effective. Is when these first came out, semiconductor
material was a precious commodity. It was not something that
was mass produced. It was not something that you could
easily get your hand ends on, and so it was
(49:01):
much more expensive. But just as Gordon More predicted way
back in the sixties, the manufacturing processes would mean that
costs would come down, efficiencies go up, and as a result,
we're able to get more efficient products. Now he was
talking specifically about integrated circuits, but as it turns out,
that kind of applies to lots of stuff. Doesn't necessarily
(49:22):
mean that the light bulbs will have next year will
be twice as bright as the ones we have this year.
So the analogy doesn't continue all the way there, but
it's still I think, semi applicable. So yeah, you can
see the differences between these these approaches. Uh, Ultimately, it's
all about again exciting atoms, and once those aboms get excited,
(49:45):
they just light up. I hope you guys enjoyed that
classic episode of tech stuff. I really liked when we
got to do the history ones where we got to
really dive into what actually happened, because frequently the stories
that we learn in history books are the fast, simple,
easy explanations, because as we really begin to understand the
(50:07):
more we look into technology, development of new technologies is
often very complicated, with lots of different people making contributions
that ultimately will result in a new technology kind of
coming to be. But it's rarely so simple as to
point to a single person and say, that person right
(50:29):
there did it. Yo. If you guys have suggestions for
our future episodes of tech Stuff, reach out to me,
send me a message on tech stuff at how stuff
works dot com, or pop on over to our website
that's tech stuff podcast dot com. They're going to find
an archive of all of our past episodes. You'll find
links to our social media accounts, and you will also
(50:50):
find a link to our online store, where every purchase
you make goes to help the show. We greatly appreciate it. Now,
I'll talk to you again really soon. M Text Stuff
is a production of I Heart Radio's How Stuff Works.
For more podcasts from I heart Radio, visit the i
heart Radio app, Apple Podcasts, or wherever you listen to
(51:12):
your favorite shows.
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