How does a diving bell work?

About 2,400 years ago Aristotle mentions the use of diving bells, apparatuses that convey divers to the bottom of the sea -- or at least below the surface of the water -- and allows them to breathe -- at least until the air runs out. Learn about the physics of this clever and ancient invention and how it's been used to sabotage enemy boats and build the Brooklyn Bridge.

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Episode Transcript

Speaker 1 (00:01):
Welcome to you stuff you should know fromhouse stuff Works
dot com. Hey, and welcome to the podcast. I'm Josh
Clark and Charles W. Chuck Bryant is with me. Um,
which means it's time for stuff you should know. That's right, man,
I got all confused right there, you're about to say. Listener,

(00:24):
it's a little close for comfort. Our shortest show ever. Yes,
how introductions work? How you doing? I'm well, sir, How
are you? I'm good. It's a little warm in here
today in um, I feel I feel like this is
to him, like a room that we're in is always
sort of warm and off putting. Well, there's like eighteen

(00:46):
NIKEA lamps in here, and I guess it feels like
it's warmer than usual. They generate some heat and that's
how they power Switzerland Sweden with Sweden Sweden. Yeah, yeah, sorry,
sweet is. Yeah, I know people are like good lord Chuck. Yeah,
you got a map as a desk bells. Yeah, you

(01:08):
have a tan map down to so um Chuck. I
want to dive into a subject that I believe you
know something about. Okay, it's called diving bells. That's the subject,
and I know you know about it because this article
that we're basing this off of, is it Chuck Bryant jam, Yeah,
I forgot all about this and I got about halfway

(01:29):
through it, and I was like that sounds like something
I'd say, Oh, really, you didn't realize that you've written it. Nope,
totally forgot. And then it wasn't halfway through, but it
was probably somewhere in the intro, that silly clever intro,
which was really not clever. Oh, I don't know. I
feel like I used to start all of my articles
like I was writing a middle school term paper. Oh

(01:51):
was it the uh where they're talking about how there's
not very many images of our early attempts to scuba
dive because quote of the lack of availability of underwater
filming techniques at the time. Yeah. Yeah, it sounds like filler.
Very very very very very remember in summer school with

(02:11):
Chainsaw and Dave Uh yeah, the Mark Arman movie. Yeah,
they had to write like a three word essay or
something like that and somebody they admired, and I think
it was Toby Hooper and or it was the or
a special effects there, but they said like he was
very very very very very very very I remember those
days counting the words. Yeah, that's not what this is. No,

(02:34):
this is a great article on diving bells. It's kind
of interesting, you know, the precursor to scuba diving. If
any of you folks out there, scuba enthusiasts you have, uh,
you know, there's a trail that was blazed many years before,
littered with dead bodies and big iron casks. Yeah, not
just dead bodies, but crippled bodies too. Like, a lot

(02:55):
of bad stuff can happen to you, and a lot
of bad stuff did happen to people before we really
understood the physics of Yeah, I mean, people still lose
their lives obviously in the pursuit of um, just forwarding technology,
but um not like they used to people. You're like,
we really owe a debt to the people who figured

(03:16):
out everything that we have and lost their lives doing it. Well,
what's spectacularly amazing to me is that not everyone died
trying to use diving bells. And we're talking like years ago. Yeah,
it wasn't you know in the early nine right, Yeah, Yeah,
Apparently by the twelve hundreds, the concept of diving bells

(03:37):
were so I guess entrenched in societies around the world,
civilizations around the world, that they were just routinely used
for all sorts of different stuff. Yeah, Aristotle wrote about it. Yeah,
back in the fourth century BC. Right, Yeah, that's a
long time ago. So he was he was the first,
I take it to mention diving bells. Who to describe them? Right? Yeah?

(03:58):
Should we read that quote? I think it's a good
but you have to read it in an aristotlely voice. Aristotelean, Um, well,
I really have no idea what ancient Greeks sounded like. Well,
the key is that no one does, so you can
just make it up. They enable divers to respire equally
well by letting down a cauldron, but this does not

(04:20):
fill with water, but retains the air, for it is
forced straight down into the vatas I just added a German. Yeah,
I was gonna say there was an eighty five percent
chance that the Greeks were gonna sound like Sean Connery
coming out of you. Yeah, that wasn't Sean Connery. Um
so yeah, So Aristotle's talking about this, and the very

(04:42):
fact that he's talking about diving bells proves at least
that the idea was in place at the time. Yeah,
there's some legends that, um, Alexander the Great, who was
actually a student of Aristotle's, used a diving bell. Yeah,
there's there's pictures drawings of you know, Alexander a Great,
like laying down or sitting down beneath the water in

(05:03):
some sort of a you know, diving bell or or
like a barrel or magic bubble some Sorry, yeah, but
we don't know if that means he just talked about
it a lot and like draw pictures of me doing this,
or if he actually tried it. Um, we're just not sure. Well,
so supposedly he used it one when he was eleven,
but then again as an older man during the Siege

(05:23):
of Tire in a three thirty two b c Um
And I looked that up and it looked like it
seems pretty reasonable, Like apparently there was some underwater obstructions
around Tire and he had some underwater divers removing him,
so he used a diving bell to go check on
their work. Not the most fantastical tale anyone could tell

(05:44):
if they were just making stuff up about him using
a diving bell. So I kind of buy that one, Yeah,
I could buy it. And of course da Vinci sketched
them out because he invented everything. Even if he didn't
properly invented, he at least sketched out ideas. You know, well, yeah,
he had a lot of great ideas that have come
to life now. The star Trek phaser really okay. But

(06:08):
Aristotle he kind of hints at the basic physics behind
the diving bell. He says that you have a capsule
that you're forcing straight down into a water the water,
and um, the air bubble, whatever air was inside is
pressed upwards so long as the vessel is concave right, yeah,
and so long as it is straight down. Like you said,

(06:30):
you don't want this thing because you know, if you've
ever played in the bathtub, and I know you do,
you you know, if you take a cup and invert
it and just push it straight down, there's gonna be water.
And then if you want to make make it poop,
you tilted on a side and the air comes out
in little bubbles. That's true, you know, because a poop
or shoot a duck. It shoots a duck. But I

(06:53):
think every kid has done stuff like that, and that's
essentially what all a diving bell is. Yeah, it's just
really heavy. Yeah, because when you have a up above
water upside down has air in it. When it contacts
the water, the air can escape any longer because of
the water surface tension, and then when you push it up,
the water compresses the air. That's right. So that's all

(07:13):
you have, like you said, at the top of a
diving belt, inside is compressed air and human beings can
breathe that. Yeah. It doesn't have to be concave though,
does it. I don't think so. But later I think, well,
I think there needs to be some sort of point
that the air can be pressed up into, but maybe not.
I've seen here they're concave, so maybe that's the best

(07:35):
designed for a diving belt. But yeah, not everybody's used
concave designs. Yeah, but I mean many were shaped like
bells somewhere, barrels like whiskey barrels, um somewhere, wooden, many
were iron um. There were They were trying all sorts
of things basically just to see if it works right,
and they figured out like, the heavier the better, because
this thing had to be able to go down to

(07:57):
the to the bottom of the sea, whatever depth that was,
and not tip over. Yeah, it couldn't tip over, and
it had to be balanced too, so you had to
have ballasts. If you weren't using an iron diving bellet,
you had to put weights on it and they had
to be balanced or else it would tip over. It
was a big deal. Yeah, And I think the key
here is this is breathable air, right like Um, It

(08:22):
depends on how deep you are and how big your
bell is, obviously, but I think one example I gave
in here was if you have a ten foot tall
bell down, that's only about eleven inches of air. Um. Now,
I don't think they were going that deep back then,
or at least they were not smart to do. So, No,
those are the ones that died, that's right. So one

(08:46):
of the other problems that these people faced aside from dying,
because they went too deep and ended up with just
eleven inches of air. Yeah. Now we should point out
that before we go any further physically speaking, that that
by volume, that's eleven inches of air. But that's still
the same amount of air that filled up the diving

(09:08):
bell above water. So right, it's compressed, So you have
compressed there, so all those oxygen molecules are still there.
They're just in compressed format. The problem is if you're
in there, you're compressed too, right, And when you're in
that state of compression, UM, the oxygen and the nitrogen

(09:29):
in your bloodstream get compressed as well and they dissolve,
which isn't a problem with the oxygen because the tissues
are surrounding tissues absorbed that oxygen and they love it.
It's like yelling to them. But the nitrogen remains dissolved
in the blood until you decompress. Then you have a problem.

(09:50):
Then you have a radio head out one. Do they
have one called the Bents? Yeah, I didn't know. It's
great one. It was the one that preceded okay computer
sort of. Did they make a bad album ever? No,
that's a good point. Yeah, that's what the Bends is,
and that can um when the when the nitrogen UH

(10:11):
tries to escape, it forms little bubbles that block blood vessels,
and that's why you can have a stroke or a
heart attack if you ascend too quickly, and it can
go to your joints and cause excruciating pain. I imagine crippling.
Remember I mentioned being crippled before. Yeah, you've suffered the bens. No, no, no,
Earlier I said, like, you said that she's littered with

(10:33):
dead bodies and and crippled bodies. I feel like we
talked about my my life long crippling. Well, momentarily I
thought you meant then, Okay, I thought I remembered many
moons ago you mentioning Scooba diving something about the bens.
I've never had the bend. Okay, Yeah, of poor Scuba Cat. Yeah,
if he'd gotten the bens, I don't know. Wonder Scooba

(10:55):
Cat still around. I don't know who's kind of old already,
wasn't he? I don't remember? Boy, that was a winner.
So uh yeah, when you come up too quickly, the
nitrogen in your blood undissolves, forms bubbles, blocks your blood vessels,
blocks your joints, causes tremendous pain, strokes, death, all that stuff. Right,

(11:18):
So when you're an ancient bell diver, I guess is
what you call just that, right? A bell diver seems right? Um,
And you were down for very long, too deep, and
you came up too quickly, you're in a lot of trouble,
that's right. And they made end up even understood the
bents at that point. Imagine they didn't. They're like he
just got the diving bell sickness right again. Yeah, it

(11:40):
was because he sinned or something like that. He upset Zeus.
So things when I went on like this for quite
a while, UM, through the Renaissance into the sixteenth century,
people were using these diving bells. It was all well
and good. They were having a blast down there, having parties.
And then at some point people were like, you know what,

(12:01):
I bet we could make this better, right, you know,
these guys keep running out of air down there and dying,
or they run out of air and they have to
come up too quick and they get the bend. So
how can we improve this? Or they're only fourteen feet
down sitting in a bell and what's the point, which
is magnificent, but the ship that we need to get
to is a hundred feet down. Yeah, exactly, like they

(12:23):
needed this. They wanted to have applications they could use
like two build things or repair things or get you know,
pirates booty exactly. And speaking of pirates, check Sparrow does
this with a canoe in the first UM Pirates of
the Caribbean. Yeah, he turns a canoe upside down and

(12:43):
like walks along the ocean bottom and I don't remember
how he pulls the canoe down. Technically speaking, it's possible
if he pulled it straight down, I think the magic
of Disney, but I don't think it's it's physically possible
what he did. Just just want to make or than
anybody who really liked that part pooh poo it okay,

(13:05):
so uh. In the late sixteen hundreds, it was a
Frenchman named Dennis Papine and m He was one of
the first dudes that said, you know what, I think
we can get some fresh air into there, and very
smartly and simply he used hoses and bellows that you know,
the bellows were outside obviously up on you know, the boat,

(13:27):
and they had dudes manning the bellows and pumping fresh
air in there. Yeah, and it wasn't even like difficult.
You didn't even have to navigate like where to put
the hole in the top of the diving The hose
literally just goes under the bottom and up inside and
then the air just presses up super easy. Yeah, so
you've got fresh air now. Yeah, they can stay down
there longer. That's all that's solved, basically, But it's still

(13:50):
not pressurized. The air they're pumping in isn't pressurized, that's true.
So they couldn't go any deeper. They could just stay
down there and do whatever the heck they were doing
sitting in these cast iron bells. Right, So we we
invent diving bells in at least the fifth century b C.
We have to wait until the sevent century a d

(14:13):
Before we make a real innovation to them. Now we
have a whole other obstacle pressurizing these things. How long
do we have to wait to overcome that? One? A year?
It's true. Uh, And it took an Englishman to do so.
Edmund halle Um. He basically attached these wooden barrels, he's

(14:35):
weighted wooden barrels to the diving bell and they could
be brought up and down, and they contained air at
the bottom of each of these as a whole. Uh,
that allowed water to come in, forcing the air up.
And at the top was a hose that ran from
that barrel to the bottom of the diving bell, and
there was a faucet. So basically, whenever it was it's

(14:57):
sort of like having air tanks down there. Whenever they
to um more pressure, you know, if they were trying
to equalize things. They would just turn their little faucet
and allow air in, and once the barrel was empty,
they would pull the barrels up, um I guess refill
them with air, which probably meant just opening the top

(15:17):
and then closing it again it's filled up, and then
lower it back down there and all of a sudden
you could control the pressure. And that was the same
um Halle who uh named a comment after himself. It
was no way that guy was all over the place
renaissance man. Yeah, yeah, that's where that word comes. There's

(15:38):
a post renaissance renaissance man. That's so. Yeah. So now
we have pressurized diving bells, right yeah, and basically equal
to that of the surrounding water. So that means you
can go deeper and stay down longer. You can you
you run out, like if the water starts to creep up,
you just add more pressurized air and it pushes the
water back down like it keeps the water at baby,

(15:59):
because it's at the same pressure. So to the water,
whatever is inside the diving bell might as well just
be more water. It doesn't have this crazy urge to
fill the diving bell up any longer because there's something
they're just kind of goes along. It's happy way to
the Mariana Trench. It's right. And I bet there was
some seventeenth century David Blaine that very shortly afterward it

(16:21):
was like, I can stay down here for two months,
and people like, who cares? Well? The horrible thing was, uh,
when you added pressurized air. Again, you're pressurizing. That's just
the diving belt, but the people. Yeah, so to become
pressurized to go down in a diving bell was a
pretty horrific thing to endure in and of itself. Yeah,

(16:42):
I guess um when they built the Brooklyn Bridge to
you know, the two towers that that, I guess that. Yeah,
those are down almost to the bedrock. They were going
to go down the bed rock, and then they found
out like there's some pretty stable aggregate defeat above bedrocks,
so they just planted them on those. But um, to

(17:05):
construct those, they had to drop these huge casans, which
are basically like giant structural diving bells, and they pressurized
them and it kept the water of the river out,
so like literally the river's just flowing around this stuff.
But there's men working in these things and they'd have
to pressurize before going in them, and it was just

(17:27):
like this. Their ear drums would burst once in a
while as they were being pressure because it wasn't like gently,
it was like, you know, I guess it was better
than just walking right into the casson, but it was
still pretty rough. And then they go and working there
for a couple of hours and then come out and
hopefully not get decompression sickness to bends. But actually the

(17:49):
project manager, the son of the designer of the Brooklyn Bridge,
Washington Row Billy is the Sun, he suffered a lifelong
crippling from decompression sickness after going and inspecting some of
the work in one of the Kim something coming out
too quickly. Well know, a lot of people died, and like, uh,
I enjoy walking across the Brooklyn Bridge, as many New

(18:09):
Yorkers do, and you should think about that next time
you're doing so. Yeah, that like people gave up their
lives too, so you could like say snarky things and
Instagram photos of yourself and all the other things that
you do. Um, there's a really great Kim Burns documentary
on the construction of Brooklyn Bridge. Who I haven't seen
that one. It's good. It's like a straight up PBS one.

(18:30):
No frills. Well, he's not about frills. He just moves
pictures like around and hands in and out. This may
be his least frilly. Okay, yeah, I'm not knocking Kimburns.
I like a good Kimburns. Well you'll probably like this
one though. So uh. A hundred years after being able
to control the pressure with bellows and that the barrels,

(18:50):
I'm sorry, um and English and other Englishman, a scientists
named John Smeaton invented an actual diving air pump in
and it was on the surface obviously, and took like
four guys to operate it. Um. And it was basically
like Dennis Peppine's original plan, but it was just mechanized.

(19:11):
So they were able to build like big ones like people.
There's many's like twelve people could go down and rush
things and like have a party if they wanted to.
They made windows eventually, Yeah, they put electricity in them.
Yeah that's a little scary for that time period. Oh yeah,
wouldn't I don't know, I don't know if I would
have trusted that. Yeah, I wouldn't be you know, seventeen

(19:33):
or early and we just discovered electricity. Now, let's put
it in under water. And they used them for, like
you said, building bridges and repairing docks, and early saboteurs
would sneak up underwater to um cut the anchor lines
of enemy ships. Really, that's a very handy use. And
so you dug up a cool story about um was

(19:55):
that this year it was just this May. Yeah, a
guy named Perrison O'Kenny at twenty nine year old Nigerian
boat cook was on a tugboat, a Chevron tug boat
and in the Atlantic and it capsized and he was
eventually through all this, you know, capsizing and tumbling around
and water flowing in and sinking a hundred feet yeah,

(20:16):
and sinking of course, ended up in a bathroom trapped
with air. Yeah, sort of like the same concept of
a diving bell. And people wondered he'd survived after sixty hours.
That's a good sixty hours. But physicists were like, well,
w how did this happen? Yeah, but you probably shouldn't
have been able to live that long down there, right,
they were. The press reported that he had something like

(20:39):
four ft of air something like that, and um, yeah,
the the chamber that he was in was only about
four ft high, So sixty hours of air shouldn't have worked.
It shouldn't have kept him alive because about it, like,
you're breathing, even if it is pressurized there, you're breathing air,
you're also exhaling carbon dioxide, and when the the ratio

(21:02):
of carbon dioxide or the percentage of it gets above five,
things start to go horribly awry and you die shortly
after that. Yeah, I didn't realize that lack of oxygen
isn't what kills people. It's too much CEO two. Yeah,
that's pretty interesting. Yeah, it can happen when you're on
a ventilator. UM. That's apparently a big risk. When you

(21:24):
innobate somebody's the ox the CEO to build up, you
can kill him. So anyway, why didn't this guy die? Well,
it turns out with pressurized air, especially when it's um
pressurized against cold water, c O two is readily absorbed
by that water around it. So when he was exhaling,
the oxygen was remaining, but the c O two is

(21:45):
basically being wicked away. And since that c O two
or the the air bubble that he was in was pressurized.
He was a hundred feet underwater um which actually helped him. Right,
he had a lot of oxygen. A bunch of oxygen
was just pushed into this little area. But the CEO
two is being wicked awayne That's how he managed to survive. Yeah.
It said for every ten ms you descend um one

(22:07):
atmosphere is pressure of pressure is added and it makes
it more dense, according to some lawmaker named Boil, according
to Boyle's law. And so since he was thirty meters below,
it became more dense by times four. And so that
meant that he didn't need as much air as you

(22:28):
would think for someone that's under underwater. And you know,
so how much did he need, like you need a
day of air? So he only needed six cubic meters
in the end because of the temperature of the water
and how deep he was. Right, and and also, I mean,
don't remember this a lot of air compressed into the
same amount of area. All those molecules are still present, Yeah,

(22:50):
they're just in a smaller amount of area. They also
think though, that it was connected to another air pocket,
which probably helped even still, the guy survived in an
impromptu inadvertent diving bell a hundred feet below the surface
for sixty hours. Dude in the dark under the ocean
with his head next to a toilet man, and they

(23:11):
said that he could hear the sea life scavenging on
his dead crewmates. That's perfect. That happened this May. Yeah,
not in like eighteen twelve. In May. Yeah, so there
you go. By the way, we'll insert this right now
because it's a good place for it. You were you
you were out of town. Did you hear about the

(23:32):
whole Sharknado thing. Yeah, you predicted Sharknado. I invented it. Yeah,
that's pretty impressive. For those of you don't don't know.
Sharknado was a very cheesy movie on a network that
UM aired a couple of weeks ago and blew up.
Blew Up didn't get as many viewers from the blow
up as they would have hoped, But um I watched it.

(23:54):
It was very funny and fun It wasn't dumb. Oh yeah,
it was terrible, but you know in that way. It
wasn't one of the guests from two and no on it. Yeah,
Iron's ear ring was in it. Terror Fred who uh oh, yeah,
she's looking rough. You mean I were out of the
country and we heard about this that's Sharknado. So thankfully
one of our listeners um alerted me to the fact

(24:16):
that I invented Sharknado because in the desert, can it
really rain frogs? Episode? Um, I say this, Uh no,
I mean I think they're light, because that's the whole point.
Even an updraft from a water spelled two miles an
hour isn't going to be picking up you know, great
white sharks. Right, that's that's a movie for you, raining sharks.

(24:42):
So thanks to fan Todd Waters for bringing that to
my attention. That's impressive. You very clearly. I even said
a movie. Yeah, you invented Sharknado. And this thing was
released a good year ago, right, it was I think
May of two thousand twelve, so that was almost a year.
But for Harrison o'kine survives in a diving bell, all

(25:03):
sorts of stuff coming together, doing the bold as feeling
the flow. So I don't know if I can sue anybody,
but I'm looking into it. Have you, I see you
should always ask before you sue, like yeah, sure, so
give me some give me some cabbage, some bread. Little
shark Nato cheese. I think we should bring back bread
for money, bringing a little bread. Yeah, all right, so

(25:27):
they sent me bread though that would suck with like
a note that decisions want shaped like a shark. Yeah,
maybe we should bring back bread into the regular vernacular
and then you ask them. Okay, okay, that's our plan,
all right, So sorry about that sidebar. I just want
to give myself credit words. You should be very proud
of that. Thanks. Um. Hey, I know I want a

(25:48):
good movie idea comes along, I'm all over it. You
and Iron's earing. Uh. If you want to learn more
about diving bells, you should type those two words into
the search bar at how stuff works dot com and
it will bring up this delightful little article written by
a young exuberant Chuck Bryant. And since I said exuberant,

(26:11):
it's time for a message break. And now it's time
for listener meal Chuck. Whether you like it or not,
I hope you're ready. We heard from another teacher. We'd
like to read these. Hey, guys, the reason I'm writing
it is to tell you how much stuff you should
know aways help me during my first year of teaching.

(26:33):
I am twenty four, just finished my first year as
a high school social studies teacher. Alight. This year, I
taught law and justice and ap psychology. Law and justice
that's awesome, and a p psychology. Yeah, well rounded. Since
I listened to a huge bulk of your shows. When
I was preparing various lessons, I used the information that

(26:53):
I had on different podcasts I'd heard on different podcasts.
Then I thought, you know what, I should just play it.
I'll get even lazier and just play the show. Um.
The podcast were a big hit with the kids. They
got a break from hearing my voice and I got
a break from talking stuff you should know. Is also
great UH for teachers because the articles you guys use

(27:15):
for the podcast are well researched and written. Thank you.
I don't have to worry that you guys are just
making up information, and if you are, don't tell me. UM.
Students said the winner of their all time favorite UH
in class was how Barbie works that that's probably my
favorite too. That's a good one. I created a pretty
awesome power point to accompany it, and I attached it

(27:38):
and I looked at it's really neat actually. Um. We
discussed how Barbie and other toys can influence gender identity,
embody image and developing children. UM. Overall, some of the
podcasts up streamed UM Japanese and tournament camps do right
your privacy when you die? UM. In psychology, I hit
on concussions, uh, Monkhalsen syndrome, Yeah, hypnosis, lobotomy is and PTSD.

(28:03):
Remember lobotomy that was one of the ALLFENDESCA. We should
have called it Lobotomy's heart. We love my lobotomy On MPR,
do you remember, Oh yeah, that dude, Yeah, that guy
here's our hero. What's his name, Howard something? Yeah, Howard.
Just to tell you guys again, thanks a lot for
making my job easier because you use classroom appropriate language

(28:26):
and report factual research based on evidence and information. You're
an amazing classroom resorts resorts. Did you say there? Did you, Misspella?
I did? Okay, keep them coming, Carly Brown, But thanks
a lot, Carly Brown. We appreciate that, Miss Brown, as
your students probably calling you. That's right, Thank you, miss
Brown for letting us know that. We like to know

(28:48):
that we're helping shape young minds for the better. That's right. UM.
And we do use classroom appropriate language, don't we never
termed it that. All right, Well let's see chuckers, Um,
what should we say? Anything you want to hear about? Uh,
if you have invented something, because I've invent into snowboard too.
Remember no, I don't remember that. I have a crayon

(29:11):
drawing from when I was six of of the skiboard. Yeah,
it's a guy going down as a ski slope on
a little skateboard of skis on. Wow. So I've invented
two things, the Sharknado and the snowboard. So if you
haven't inadvertently invented something, that's a great one. Man, we'd
love to hear about it. Yeah. Um, you can tweet
that to us at s Y s K podcast. You

(29:32):
can post it on our Facebook page at Facebook dot com,
Slash you Should Know. You can send us an email
at Chuck and I will both get to Stuff Podcast
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home on the web. It's a little website known as
Stuff you Should Know dot com. For more on this

(29:55):
and thousands of other topics, does it how stuff works
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