Latest / Stuff You Should Know / How X-Rays Work
Transcript
- 0:00Speaker 1: Welcome to Stuff you Should Know from House Stuff Works
- 0:04Speaker 1: dot com. Hey, and welcome to the podcast. I'm Josh
- 0:13Speaker 1: Clark with Charles W. Chuck Bryant as always, and there's
- 0:16Speaker 1: Jerry over there fiddling around with stuff. So it's stuff
- 0:20Speaker 1: you should know the podcast, not stuff you should know.
- 0:23Speaker 1: The movie. That's right. You know we were one secrecy
- 0:27Speaker 1: about that. That'd be a good movie. That'd be a
- 0:29Speaker 1: bad movie. I don't know, man, I could go either way.
- 0:32Speaker 1: I always see I imagine it like strange brew. Oh yeah,
- 0:37Speaker 1: yes they could. Uh, they could based it on the
- 0:39Speaker 1: Stuff you Should Know tell all book I'm writing. Oh yeah,
- 0:42Speaker 1: that would be exciting. That would be very exciting. I'm
- 0:45Speaker 1: looking forward to that book like a lifetime movie the Week.
- 0:48Speaker 1: Do you like um switch people's names like in my
- 0:51Speaker 1: um Joe Joe Clack. Yeah, exactly. No, it's sort of like,
- 0:58Speaker 1: uh like did you see the uh Saved by the
- 1:00Speaker 1: Bell movie? Oh yeah, I didn't Screech write a book.
- 1:04Speaker 1: It was based on a book by Screech. Right, yeah.
- 1:06Speaker 1: It wasn't it like all sex and drugs and stuff?
- 1:09Speaker 1: Oh it was, you know, it was a bunch of
- 1:10Speaker 1: teenagers in Hollywood. So sure, there was some of that
- 1:14Speaker 1: in there, but it was I didn't read the book.
- 1:16Speaker 1: But the movie was bad and not nearly as salacious
- 1:19Speaker 1: as you wanted it to be, right. I remember a
- 1:22Speaker 1: lot of people being disappointed, and I remember, I mean
- 1:25Speaker 1: I recalled it like two weeks ago when people were
- 1:28Speaker 1: talking about it when it came out. It stunk. I'll
- 1:30Speaker 1: watch Emily and I'll watch some of those, um just terrible,
- 1:33Speaker 1: terrible biopics occasionally on TV, and it's it can be fun.
- 1:38Speaker 1: Like we watched the who was the one actor Brittany Murphy?
- 1:43Speaker 1: The Britney Murphy story? Oh? Really? Does she have a
- 1:46Speaker 1: heck of a story? Is she alive still? Or did
- 1:47Speaker 1: she die? She passed away because under kind of weird
- 1:50Speaker 1: circumstances because she and her husband both passed away within
- 1:54Speaker 1: weeks of each other, and there were all these strange
- 1:57Speaker 1: claims that her house was poisoned, that they were poisoned,
- 2:00Speaker 1: and um, yeah, it was it was fun. What's your
- 2:05Speaker 1: take on it? Oh, I don't know, you just that
- 2:08Speaker 1: the movie wasn't very good. Who played Brittany Murphy? Do
- 2:11Speaker 1: you remember someone who didn't look very much like Brittany Murphy?
- 2:18Speaker 1: Julie Bowen but I was right. The Ashton Kutcher guy
- 2:21Speaker 1: was pretty good, though. I gotta say Steve Jobs played him.
- 2:23Speaker 1: They should have just gotten Ashton Kutcher to play himself.
- 2:26Speaker 1: He's not doing much. He's not my two and a
- 2:28Speaker 1: half Men. I don't know. That's got to require fifteen
- 2:31Speaker 1: minutes of work a week. He's selling cameras. Do you
- 2:34Speaker 1: remember when that whole Two and a half Men thing
- 2:35Speaker 1: was going down? We were in l a And for
- 2:38Speaker 1: the one and only time in my entire life, I
- 2:40Speaker 1: see John Cryer that day. Oh, during the Charlie Sheen meltltown,
- 2:44Speaker 1: like the day of the meltown, like it happened at night.
- 2:47Speaker 1: And within eight hours I saw John Cryer for the
- 2:50Speaker 1: first time in Personeta McDonald's did you feel Duckie? No,
- 2:54Speaker 1: I left him alone. He looks sturessed out. Well, yeah,
- 2:57Speaker 1: he's probably like, my career is going down the tubes.
- 2:59Speaker 1: But little did he know he's a survivor. His career
- 3:02Speaker 1: is just fine. So x rays, Yeah, that's what we're
- 3:06Speaker 1: talking about, right, yep. The lightest part of this podcast.
- 3:10Speaker 1: I like this one. This one. It's one of those
- 3:12Speaker 1: things where if you can just hang on by your fingernails.
- 3:16Speaker 1: It can click and then you lose it again, but
- 3:19Speaker 1: that means that it could click again later on. That's
- 3:23Speaker 1: what I like about it. Good. I'll leave that to you.
- 3:26Speaker 1: I got lots of other stuff about it. I totally
- 3:29Speaker 1: understand good Good. Um, So, have you ever broken anything
- 3:32Speaker 1: and needed an X ray? Or has it all just
- 3:34Speaker 1: been dental stuff? You know? Dude? Never broken a bone?
- 3:38Speaker 1: Knock on wood? Yeah, I mean I've had My injuries
- 3:41Speaker 1: were always um stitches. I was always getting busted open
- 3:46Speaker 1: rocks and sprinklers, and I was always getting cut and
- 3:49Speaker 1: sewed back up. But I never broke a bone. That's great. Yeah,
- 3:53Speaker 1: you should probably knock on lee more time, just to
- 3:55Speaker 1: be safe. Uh So, Yeah, all of my X rays
- 3:58Speaker 1: to have been like just going to the dentist or whatever.
- 4:00Speaker 1: You never had a bone broken? I don't want to say,
- 4:02Speaker 1: because I I don't even know if knocking on wood
- 4:04Speaker 1: will do it on laminate ikea. That would just be
- 4:07Speaker 1: so horribly interesting if both of us broke a bone
- 4:12Speaker 1: after this. Yeah, and we're at the age where like
- 4:14Speaker 1: you should break bones when you're a kid, were you
- 4:16Speaker 1: like whatever? I get a cast at this age. It's
- 4:18Speaker 1: it's a drag. Yeah. I remember reading like a Tom
- 4:21Speaker 1: Clancy novel and like some kid got an arm torn
- 4:25Speaker 1: off or whatever, and one of the surgeons was like,
- 4:27Speaker 1: if the arms in the same room as the kid,
- 4:29Speaker 1: it can be healed. That doesn't hold true in your
- 4:32Speaker 1: Tom Clancy's age. No, So, um, you are familiar with
- 4:38Speaker 1: X rays, so you've seen them before You've watched the
- 4:40Speaker 1: er surely, Yeah, I mean I've had X rays for
- 4:43Speaker 1: like the dental ones, like you said, and then um
- 4:45Speaker 1: just other various like uh like chess X rays for
- 4:49Speaker 1: sicknesses and things like that, which I think maybe a
- 4:51Speaker 1: little frivolous to be honest, Yeah, and kind of dangerous
- 4:54Speaker 1: really conceivably, which we'll get into later. But um, did
- 4:58Speaker 1: you were you familiar with X raised it all beyond that?
- 5:01Speaker 1: Did you know that they were invented or discovered accidentally? Yeah?
- 5:05Speaker 1: I did know that. Um I did not. That's one
- 5:07Speaker 1: of the few things I know. I thought I saw
- 5:09Speaker 1: a little like Quickie short on something like it might
- 5:12Speaker 1: have been actually Science Channel. I looked all over. The
- 5:14Speaker 1: most I could find was a dude on siemens Um
- 5:18Speaker 1: just describing it in the most flat affic I've watched
- 5:23Speaker 1: video yeah, I got to five and five wind Low
- 5:26Speaker 1: and I was like, forget this. Yeah, if I've never
- 5:28Speaker 1: loaded for me, I watched the other fourteen though, and
- 5:30Speaker 1: the whole time I was going, man, these are a
- 5:33Speaker 1: minute long, please join them all together into one six
- 5:36Speaker 1: minute video. You know. It was so weird. Yeah, it
- 5:38Speaker 1: was pretty silly, but and he was he was good.
- 5:41Speaker 1: He was just very dry. Yeah, and they spent zero
- 5:45Speaker 1: pennies on any kind of soundtrack or anything like what
- 5:49Speaker 1: if he grabs papers? You hear papers wrestling in the classrooms.
- 5:53Speaker 1: It was. It was pretty straightforward. Yes, but that's a
- 5:57Speaker 1: very wind about, round about way of getting to uh,
- 6:02Speaker 1: it's discovering German physicists named Wilhelm uh Runtigan, and he
- 6:09Speaker 1: was testing whether cathode rays could pass through glass. And
- 6:13Speaker 1: he saw that the fluorescent screen was glowing when he
- 6:17Speaker 1: turned on his electron electron beam, which wasn't a big deal,
- 6:19Speaker 1: but he was like, wait, he's got cardboard around it, right,
- 6:22Speaker 1: there shouldn't be any visible light escaping, which is silly
- 6:25Speaker 1: to think of. Now, well, yeah it is, but you
- 6:27Speaker 1: have to put yourself in his shoes, like X rays
- 6:29Speaker 1: hadn't been discovered because he was literally on the verge
- 6:32Speaker 1: of discovering them. Right then, that's right, and uh yeah,
- 6:35Speaker 1: so he was like, this is very curious that this
- 6:36Speaker 1: is fluorescing. Yeah, and he noticed other things were glowing,
- 6:40Speaker 1: and eventually he started putting other objects between the tube
- 6:44Speaker 1: and the screen. They glowed the screen. Did that is
- 6:47Speaker 1: finally put his hand there. I read his wife's hand.
- 6:50Speaker 1: Oh really, it's like, come in here for a second. Yeah,
- 6:53Speaker 1: I want you to try something. Saw bones projected and
- 6:58Speaker 1: then I guess probably poo pooed his pants. It's a man,
- 7:03Speaker 1: I think, come onto something here. Yeah. It was really
- 7:05Speaker 1: that quickly. He was like immediately the application was clear.
- 7:10Speaker 1: It wasn't one of those things where it took twenty years.
- 7:12Speaker 1: He's like, hold on, you can see bones. This could
- 7:15Speaker 1: be really helpful. And he won a Nobel Prize very rightfully, so,
- 7:19Speaker 1: the first one ever for physics, and he named him
- 7:22Speaker 1: X rays because he didn't know what the heck it was, no,
- 7:25Speaker 1: exactly kind of signing your name he'd probably right. I
- 7:28Speaker 1: think he assumed that later on future scientists would fill
- 7:32Speaker 1: in the blanks, but they were like, no, we're cool
- 7:34Speaker 1: with X rays. Well, he probably thought that someone would
- 7:36Speaker 1: eventually call it like the Rundkin ray for something. He
- 7:39Speaker 1: wasn't much of a self promoter. He was just like
- 7:42Speaker 1: all is calling X rays as a place hold. And
- 7:45Speaker 1: he didn't patent any anything, you know, he never like
- 7:47Speaker 1: made money off of it. Uh. And then just as
- 7:50Speaker 1: his wife had hand cancer as a result. Really I
- 7:53Speaker 1: was laughing, but it was it was just a joke.
- 7:57Speaker 1: He can proceed with the la plus. I've never heard
- 7:59Speaker 1: of hand to cancer. It's got to be out there. Uh.
- 8:03Speaker 1: And then a couple of years later they were already
- 8:05Speaker 1: using it. Um in the Balkan War was the first
- 8:07Speaker 1: time it was really put to practical use. The first
- 8:10Speaker 1: Balkan War, the one around World War One. Well, oh
- 8:15Speaker 1: that Balkan War. Um. I didn't know that existed until
- 8:18Speaker 1: just now. And they said we can see bullets and
- 8:21Speaker 1: trapnel and stuff now, um, which is helpful. It is
- 8:24Speaker 1: extremely helpful. So like this guy Rundkin discovers X rays
- 8:28Speaker 1: and their most practical application and one fell swoop basically
- 8:33Speaker 1: and a little further study revealed the X rays are
- 8:36Speaker 1: actually just a another part of the electromagnetic spectrum, of
- 8:43Speaker 1: which radio waves, microwaves what we call visible light. UM.
- 8:48Speaker 1: What else is there. Well, I've got handy wallet electromagnetic
- 8:53Speaker 1: spectrum card, and X rays fall between gamma rays and
- 8:59Speaker 1: ultra bio let rays on that spectrum, which are all below.
- 9:03Speaker 1: Well you say below, I don't know if it's it's
- 9:06Speaker 1: not really an above or below situation. Visible light and
- 9:10Speaker 1: then infrared, microwaven, radio waves, so it would be a
- 9:13Speaker 1: higher or lower frequency, because that's how the whole thing
- 9:15Speaker 1: is divided. Yeah. So, like the visible spectrum of light
- 9:19Speaker 1: consists of electromagnetic radiation that has a frequency, a wavelength
- 9:25Speaker 1: that our eyes are sensitized too, so we can pick
- 9:28Speaker 1: up visible light. There's plenty of other stuff on this
- 9:31Speaker 1: spectrum of electromagnetic radiation, and all of it is delineated
- 9:35Speaker 1: by the frequency the wavelengths. So at the highest end
- 9:39Speaker 1: you have gamma rays, They're like, yeah, that means the
- 9:42Speaker 1: squiggly line is very close together exactly. And then on
- 9:45Speaker 1: the farthest end you have radio waves. Are like, and
- 9:50Speaker 1: that means the squiggly line is far apart exactly, and
- 9:53Speaker 1: that is called chuck science. That's good stuff. Yeah. So
- 9:58Speaker 1: back in my wallet, x RA right next to the
- 10:01Speaker 1: what else you have in there? I just have my
- 10:04Speaker 1: PEPs blue ribbon membership, which actually do do you really? Yeah?
- 10:09Speaker 1: But I've had it for like twenty years. When you
- 10:13Speaker 1: you got it, when you're like seven eight, flatter me. So, uh,
- 10:18Speaker 1: X rays fall, I guess we're about in the well, Yeah,
- 10:22Speaker 1: the higher and they have a higher frequency as far
- 10:24Speaker 1: as the electro magnetic spectrum goes. But the point is
- 10:27Speaker 1: is that it is ultimately the same thing. It's a
- 10:30Speaker 1: it's a type of electro magnetic energy that is carried
- 10:34Speaker 1: on a photon, which is a particle of what we
- 10:36Speaker 1: would call light. Yeah, and we talked about photons a
- 10:39Speaker 1: plenty in the show, and uh the same like photons
- 10:44Speaker 1: produce the visible light that we can see photons blast
- 10:48Speaker 1: out from the sun. How long does it take? Like
- 10:51Speaker 1: it takes like a hundred dozen years to get from
- 10:53Speaker 1: the core to the surface and then like eight minutes
- 10:56Speaker 1: to get from the surface to Earth. That's right, man,
- 10:58Speaker 1: that's I love that pack. So this is the only
- 11:01Speaker 1: part I understand, So I'll lead with it. If you
- 11:04Speaker 1: want to imagine um an atom, the nucleus of an
- 11:07Speaker 1: atom and rings around that adiom adium and adam as orbitals. Uh,
- 11:15Speaker 1: when an electron drops to a lower orbital it releases
- 11:19Speaker 1: energy in the form of a photon, and the electron
- 11:22Speaker 1: will always drop to the lower orbital. That's right. So
- 11:25Speaker 1: like if an orbital is if an electron is kicked
- 11:28Speaker 1: off of a lower orbital, an electron in the higher
- 11:30Speaker 1: orbital goes and drops down to that one. Yes, And
- 11:33Speaker 1: depending on how far it drops is going to determine
- 11:36Speaker 1: the energy level of that photon that it's that it
- 11:39Speaker 1: releases his energy when it drops, right, yeah, because it
- 11:41Speaker 1: doesn't have to, you know, drop more than one orbital.
- 11:44Speaker 1: You can skip down I don't even know how far,
- 11:46Speaker 1: but a long way, yeah, I can. And like you
- 11:48Speaker 1: said that, the greater the distance between the two orbitals are,
- 11:51Speaker 1: the greater the energy differential, the greater the energy that photon,
- 11:55Speaker 1: when released, will have, right, that's right. And as we said,
- 11:59Speaker 1: photons are the energy carriers of the electromagnetic spectrum. And
- 12:03Speaker 1: depending on that energy or the frequency the wavelength of
- 12:07Speaker 1: that photon, that determines what kind of photon it is, right,
- 12:11Speaker 1: whether it's a radio photon or a an X ray photon,
- 12:15Speaker 1: or a photon that we can see that's in the
- 12:17Speaker 1: visible spectrum. That's right. Uh. Sometimes when these photons are
- 12:21Speaker 1: flying around, they will collide with other atoms, and sometimes
- 12:26Speaker 1: those atoms absorb that photons energy and then kick it
- 12:29Speaker 1: up to that higher level again, right, but it has
- 12:32Speaker 1: to be from what I understand, and I saw that
- 12:35Speaker 1: there's like, of course it's science, so there's like atomic science,
- 12:39Speaker 1: so there's little exceptions to this and that. But from
- 12:42Speaker 1: what I can see, Chuck, there is the energy of
- 12:47Speaker 1: that photon has to exactly match the energy differential between
- 12:52Speaker 1: one orbital and another on an atom so that it
- 12:56Speaker 1: can kick it up, so that it hits that one
- 12:59Speaker 1: electron and lower orbital kicks it up to the higher
- 13:02Speaker 1: orbital and thus transfers its energy, which means that atom
- 13:06Speaker 1: just absorbed that energy that that photon was carrying. Right.
- 13:10Speaker 1: But if it's a little less, it's not going to
- 13:12Speaker 1: have the energy to kick that electron up, which makes
- 13:14Speaker 1: sense to me, right. But if it's a little more,
- 13:18Speaker 1: this is what doesn't make sense to me. It doesn't
- 13:20Speaker 1: kick the electron up, and then the photon carries on
- 13:24Speaker 1: in a diminished energetic state. It just doesn't do anything.
- 13:28Speaker 1: It doesn't interact with that. It has to be exactly, say,
- 13:31Speaker 1: like the energy differential between orbits is eight, so photon
- 13:36Speaker 1: has to have an energy of eight or else it's
- 13:39Speaker 1: not gonna do anything with the atom. That's right, okay. Uh,
- 13:43Speaker 1: and so depending on the um, Well, let's say you
- 13:48Speaker 1: have a radio wave. They don't have very much energy,
- 13:50Speaker 1: so they can't move electrons between these orbitals. They just
- 13:54Speaker 1: passed through things. X rays are super powerful. There's lots
- 13:57Speaker 1: of energy, so they can through things, which is key
- 14:01Speaker 1: if you want to check out your bones from outside
- 14:04Speaker 1: of your body. It is. And we're going to explain
- 14:06Speaker 1: exactly how right after this. Okay, so we're back chucking.
- 14:13Speaker 1: You tantalized everybody by saying that this, this difference in
- 14:16Speaker 1: absorption is what produces X rays. Right was that tantalizing?
- 14:21Speaker 1: I was tantalized and I even know it's coming, all right,
- 14:24Speaker 1: that's how excited I am about X rays. So consider this,
- 14:29Speaker 1: Like different atoms have different atomic weights, they have different densities,
- 14:36Speaker 1: they're just different. Like different atoms are different, and atoms
- 14:40Speaker 1: also have order called differences in radiological density. Okay, so
- 14:46Speaker 1: a really high energy, high atomic weight, very dense atom
- 14:52Speaker 1: is going to be able to absorb a lot of energy.
- 14:56Speaker 1: Smaller atoms that maybe are looser and have a lower
- 14:59Speaker 1: atomic weight are gonna get kicked around by any old
- 15:02Speaker 1: photon that wants to come along. Yeah, and that's that's key.
- 15:06Speaker 1: Like I said, if you want to see bones because
- 15:08Speaker 1: you're soft tissue. If you've ever noticed when you have
- 15:10Speaker 1: an X ray, you'll see the bones, but you know
- 15:13Speaker 1: the rest is sort of a grayish black mess because
- 15:17Speaker 1: your soft tissue has smaller atoms. Your bones, Uh, calcium
- 15:21Speaker 1: atoms are much larger, so they're gonna absorb those X
- 15:25Speaker 1: ray photons. It's exactly right to do it, really well exactly.
- 15:28Speaker 1: So um, imagine you have uh, let's say, Chuck, let's
- 15:33Speaker 1: go back and hang out with Tuck Tuck right, Oh man,
- 15:36Speaker 1: let's get back in the way back when it's been
- 15:37Speaker 1: a while. Okay, look at him over there. So here
- 15:49Speaker 1: we are in France in this cave, um Tuck. Tuck
- 15:52Speaker 1: has his hand up against the cave wall, as you'll see,
- 15:56Speaker 1: and in his other hand he's got that little straw
- 15:58Speaker 1: filled with pig meant red pigment. He's blowing it on
- 16:02Speaker 1: his hand right and now that he moves his hand away,
- 16:06Speaker 1: there's the outline of his hand right exactly. He's just
- 16:11Speaker 1: made an early stencil. He's like a banks He basically
- 16:14Speaker 1: like a caveman Banksy. But if you look at the
- 16:17Speaker 1: back of Tuk Tuk's hand, don't get too close, but
- 16:19Speaker 1: look at the back of his hand. It's covered in
- 16:21Speaker 1: red pigment, right, So if you can, if you want
- 16:24Speaker 1: to equate this to an X ray, the hand absorbed
- 16:30Speaker 1: all of that pigment and the stuff that passed through
- 16:34Speaker 1: left the picture on the cave wall. That's kind of
- 16:37Speaker 1: what happens with an X ray, except with an X
- 16:40Speaker 1: ray photograph. The X ray photons are absorbed by the denser,
- 16:45Speaker 1: calcium rich bones and they passed through the softer tissue.
- 16:50Speaker 1: So the picture that we have is the outline the
- 16:53Speaker 1: silhouette of the bones because the X rays made it
- 16:57Speaker 1: through the tissue. Didn't make it through the bones. They
- 16:59Speaker 1: made it are the tissue and onto the X ray plate,
- 17:02Speaker 1: which absorbed the picture in negative. That's right, And I'm
- 17:05Speaker 1: glad he said picture, because that's all it is. On
- 17:07Speaker 1: the other side of the human being. You know that
- 17:10Speaker 1: they're shooting the X ray at there's a camera and
- 17:14Speaker 1: you're just gonna get a regular negative and they could
- 17:17Speaker 1: make it a positive, but they leave it as a
- 17:19Speaker 1: negative because you really don't need the positive image. Uh,
- 17:23Speaker 1: And that's what they'll put on that little screen to
- 17:25Speaker 1: show you your cracked femur exactly. And they can see
- 17:29Speaker 1: the crack because some of those X rays will make
- 17:31Speaker 1: it through the gap, that's right, right, So all you're
- 17:34Speaker 1: seeing is the result of X rays that made it
- 17:38Speaker 1: through the tissue were absorbed by the bone, so those
- 17:42Speaker 1: don't make it to the plate. The ones that make
- 17:44Speaker 1: it to the plate cause the chemical reaction that gives
- 17:47Speaker 1: you your negative your X ray. And it's it's pretty simple, really,
- 17:50Speaker 1: like if you think about it, at least in principle.
- 17:53Speaker 1: It's also extraordinarily difficult to conceive of. But if you
- 17:59Speaker 1: if you understand like the principle behind it, it makes
- 18:02Speaker 1: uttering complete sense. Yeah. And it's a pretty focused shot
- 18:05Speaker 1: that they're using there. It's not like they don't fill
- 18:08Speaker 1: the entire room with X rays. You know, they've got
- 18:11Speaker 1: a thick lead shield around the whole device and it
- 18:15Speaker 1: you know, contains contains everything. It's got a little small
- 18:17Speaker 1: window that's just gonna let that narrow beam pass through
- 18:22Speaker 1: through a series of filters and basically hit you wherever
- 18:25Speaker 1: they want to hit you. Yeah, And the reason that
- 18:27Speaker 1: the they use lead is because lead is an extremely
- 18:30Speaker 1: dense uh yeah element, yes right, sure, oh god, I
- 18:35Speaker 1: hope so with a with a very high atomic number,
- 18:39Speaker 1: which means it can absorb tons of energy. Right. Yeah,
- 18:41Speaker 1: that's why you're gonna wear a lead apron. Um if
- 18:44Speaker 1: you're not, you know, if you're getting your skull done,
- 18:46Speaker 1: you're probably gonna wear an apron in your chest. Let's say,
- 18:49Speaker 1: so you're you're so this lead is being bombarded with
- 18:53Speaker 1: X ray photons and electrons and it's just taking it.
- 18:55Speaker 1: It's fine, and it's not being able to it's not
- 18:58Speaker 1: able to pass through because it doesn't have high enough energy. Um.
- 19:02Speaker 1: But yes, they when they put that little window in
- 19:05Speaker 1: the X ray generating machine, it passes right through there
- 19:08Speaker 1: in a concentrated beam. And Chuck, let's talk about the machine, right. So,
- 19:13Speaker 1: and and this is basically what we use as X
- 19:16Speaker 1: ray machines is essentially what Rooken was made, what made
- 19:21Speaker 1: was experimenting with when he accidentally discovered them. Because if
- 19:24Speaker 1: you look for X rays like they're they propagate naturally.
- 19:28Speaker 1: But I think like the X rays on Earth come
- 19:31Speaker 1: from humans. Yeah, like we generate a lot of X rays.
- 19:35Speaker 1: They don't they don't come like, you don't find them
- 19:38Speaker 1: normally on Earth. They're coming from outer space to us,
- 19:42Speaker 1: hence X ray astronomy. But the ones here on Earth
- 19:46Speaker 1: that are generated on Earth, they don't. It's not like
- 19:49Speaker 1: rocks put out X rays or something like that. We do.
- 19:52Speaker 1: We humans, humans and lead aprons put out X rays
- 19:56Speaker 1: and they use this machine like Rootkin made. Yeah. What
- 19:59Speaker 1: you have in the machine and you have an electrode pair,
- 20:01Speaker 1: a cathode and an anode, and that's inside a good
- 20:04Speaker 1: old fashioned glass vacuum tube, which, um, it's amazing how
- 20:08Speaker 1: vacuum tubes are still like the best way to do
- 20:10Speaker 1: many of these things. Well, it allows things to travel
- 20:13Speaker 1: at the speed of light easily, that's right, and allows
- 20:15Speaker 1: guitar amps to sound great. I didn't know these vacuums
- 20:18Speaker 1: in that. Oh is that a cathode tube? Yeah, yeah,
- 20:21Speaker 1: like a like the best amps are still made with
- 20:25Speaker 1: vacuum tubes. You can get solid state amps, but they're
- 20:27Speaker 1: just the sound isn't as rich, So it's kind of
- 20:29Speaker 1: like this old technology that's still superior. They're all pumped
- 20:32Speaker 1: out by hand by a ninety year old man in Tennessee.
- 20:36Speaker 1: Mr Marshall yes. Uh So the cathode is a heated
- 20:41Speaker 1: filament just like you might see in a light bulb,
- 20:44Speaker 1: and the machine's gonna pass the current through that and
- 20:46Speaker 1: heat that thing up, and then it's gonna spit electrons
- 20:49Speaker 1: off that surface, and it's gonna hit a disc made
- 20:53Speaker 1: of punksten and it's gonna draw those across the tube.
- 20:57Speaker 1: It's basically the tube is sort of the key peat, right,
- 21:00Speaker 1: because you've got the positive and the and the negative
- 21:04Speaker 1: charge the cathode and the anode, right, um, and that
- 21:08Speaker 1: difference that electrical charge draws his electrons down to the anode. Yeah,
- 21:15Speaker 1: And that force means that when those electrons hit the
- 21:19Speaker 1: tungusten anode, it knocks a bunch of electrons off, creates
- 21:24Speaker 1: a bunch of X rays in the process, and um,
- 21:28Speaker 1: you have a whole box filled with X ray radiation.
- 21:33Speaker 1: That's exactly what it is, like you're just I mean,
- 21:35Speaker 1: there there might as well be like a foot crank
- 21:37Speaker 1: to this thing, like an old sewing machine. For as
- 21:40Speaker 1: as technologically advanced as it is, there may be for
- 21:43Speaker 1: all I know, I don't know what goes on in
- 21:44Speaker 1: that other room, right, Yeah, there's some dude in there
- 21:49Speaker 1: with like his right leg is three times more muscular
- 21:52Speaker 1: than his left leg because that's the only one he uses.
- 21:55Speaker 1: So um. In addition, like I said to to X
- 21:58Speaker 1: rays being created, the the other X rays, other photons
- 22:03Speaker 1: can go on and knock more electrons off. So you
- 22:06Speaker 1: you have what's like a process of chain reactions starting, right.
- 22:09Speaker 1: It's not like one gets hit and then that's it,
- 22:11Speaker 1: and the photons creating it just hangs around until it's
- 22:14Speaker 1: beamed out. But you're just generating this huge amount of
- 22:18Speaker 1: X rays, and the X rays are also continuing to
- 22:20Speaker 1: propagate themselves because they're knocking more electrons free. And the
- 22:24Speaker 1: more free electrons you have, the more interactions you have. Right,
- 22:28Speaker 1: So one of the ways that more electrons can be
- 22:30Speaker 1: knocked off, you don't even need a direct transfer of
- 22:34Speaker 1: energy where a photon is absorbed or knocks an electron
- 22:37Speaker 1: from one orbit to another, or knocks it loose entirely.
- 22:41Speaker 1: A photon actually has this really cool um capability of
- 22:46Speaker 1: just orbiting close by the nucleus of an atom, and
- 22:51Speaker 1: when the nucleus basically draws it into its orbit, the
- 22:54Speaker 1: photon just takes a hard left turn, just bumps it
- 22:57Speaker 1: off its course. But even like the dodge via for
- 23:00Speaker 1: it has to like slow down to take a left turn,
- 23:03Speaker 1: slow a little bit, right, just a little, just a little.
- 23:06Speaker 1: But that little bit in photon world means a transfer
- 23:11Speaker 1: of energy from the photon outward. Yeah. And then the photon,
- 23:16Speaker 1: like the photon takes that left turn and and the
- 23:20Speaker 1: energy is transferred to the atom. Yeah. And one of
- 23:22Speaker 1: the byproducts. If this sounds like it's gonna create a
- 23:25Speaker 1: lot of heat, it's because it will. And in order
- 23:28Speaker 1: to combat this, they rotate this anode to keep it.
- 23:31Speaker 1: It would just melt down if you kept it in place.
- 23:33Speaker 1: And apparently there's a cool oil bath that helps absorb
- 23:38Speaker 1: heat as well, which I never have heard of that either.
- 23:40Speaker 1: It sounds oily oil bath. Yeah, it doesn't sound refreshing
- 23:44Speaker 1: at all. It sounds like the opposite of refreshing. Yeah.
- 23:46Speaker 1: Cool and oil don't really go together. Yeah, and I misspoke.
- 23:50Speaker 1: That's an electron that can be drawn too into the
- 23:53Speaker 1: nucleus of an anom appropriately enough, because they orbit nuclei anyway.
- 23:57Speaker 1: But it doesn't have to hook hook up with that them.
- 24:00Speaker 1: When it takes that hard left it admits the photon.
- 24:03Speaker 1: Like you said, that's right, And like I said earlier,
- 24:06Speaker 1: there's a camera on the other side of the patient
- 24:08Speaker 1: and it's going to record that pattern of light when
- 24:11Speaker 1: it passes through the body. And it's not so different
- 24:14Speaker 1: from a regular camera. Um. And then the and you're
- 24:17Speaker 1: just gonna get a picture, like I said, a negative image. Yeah.
- 24:19Speaker 1: And if you hook it up with a computer that
- 24:22Speaker 1: allows you to take X rays basically in slices, you
- 24:25Speaker 1: can come up with commuter computerized tomography. If you ak
- 24:30Speaker 1: a CT right, let's scan exactly. Um. If you uh,
- 24:34Speaker 1: if you use if you get a breast exam, you're
- 24:36Speaker 1: using a type of X ray called momography. Um. And
- 24:39Speaker 1: then there's a fluoroscopy, which the man in the extraordinarily
- 24:44Speaker 1: dry presentation from Siemens said, um was basically like moving picture.
- 24:50Speaker 1: It's like a movie exactly. And then he showed us
- 24:54Speaker 1: what the movie is with a flipbook, right, that old
- 24:56Speaker 1: flipbook trick. And if you listen to this podcast, I'm sorry,
- 25:00Speaker 1: I just want to apologize for both of us. Semens guy,
- 25:03Speaker 1: Oh yeah, uh, like, hats off to you for doing
- 25:07Speaker 1: that at all. Yeah, um, because he's probably saying, well,
- 25:10Speaker 1: at least that was correct, and everything I said it's
- 25:13Speaker 1: a good point, sir um. But with fluoroscopy, it's basically
- 25:17Speaker 1: like a movie of an X ray movie, and you
- 25:20Speaker 1: would do this to make sure like a heart is
- 25:22Speaker 1: beating correctly because you wanted to see it. But you
- 25:25Speaker 1: have to have an additional um instrument because as we said,
- 25:30Speaker 1: X rays will pass through tissue like heart tissue and
- 25:34Speaker 1: muscle tissue and all and blood vessels and all the
- 25:37Speaker 1: stuff you want to get pictures of using an X ray,
- 25:39Speaker 1: so you have to use something called a contrast media
- 25:42Speaker 1: for it. Yeah, a contrast agent is basically more dense
- 25:45Speaker 1: than the soft tissue. So if you want to uh,
- 25:50Speaker 1: let's say, swallow, it's usually like a barium compound. If
- 25:53Speaker 1: you want to examine like your blood vessels or your
- 25:55Speaker 1: circulatory system, you're sometimes they can inject that, or you
- 25:59Speaker 1: might drink it to see if you're doing like a
- 26:01Speaker 1: gastro intestine, like a GI tract. You're gonna swallow that stuff,
- 26:06Speaker 1: which I've never had to do. I think my dad
- 26:07Speaker 1: had to do that. Yeah, I don't think it's super pleasant.
- 26:10Speaker 1: I get the impression not too, but my dad did
- 26:13Speaker 1: as well. Yeah, it's an old guy thing, so I
- 26:15Speaker 1: should be getting one soon. Uh, and then it allows you,
- 26:19Speaker 1: you know to see him moving image. Uh. Basically how
- 26:23Speaker 1: that liquid is if there's any blockage. Uh, there's all
- 26:26Speaker 1: sorts of applications for it. Yeah, because you're that liquid
- 26:29Speaker 1: has a high radiological density, which means that the X
- 26:35Speaker 1: rays don't just pass right through your the tissue that
- 26:38Speaker 1: it's being suspended in, like your blood vessels. It absorbs
- 26:42Speaker 1: it for it. So you get a picture of your
- 26:43Speaker 1: blood vessels, your circulatory system, which is pretty cool. It's
- 26:46Speaker 1: pretty clever. It's also extraordinarily elementary and principle, my dear Watson. Uh.
- 26:52Speaker 1: And that single picture I think we you know, we
- 26:54Speaker 1: mentioned CT and momography and all that in philoscopy, but
- 26:57Speaker 1: the single picture is just called standard radiography. And that's
- 27:00Speaker 1: when you're you know, taking a photo of your skull
- 27:04Speaker 1: or your lungs, or your bones or your teeth and
- 27:07Speaker 1: so so. Speaking of the lead apron thing, man, it's
- 27:10Speaker 1: always made me kind of nervous, Like if I the
- 27:13Speaker 1: rest of my body has to wear lead apron, but
- 27:16Speaker 1: you're shooting an X ray into my head, am I
- 27:18Speaker 1: going to be? Okay? Well we'll answer that right after
- 27:22Speaker 1: this message. All right, X rays. Are they bad for you?
- 27:35Speaker 1: The answer is yes, uh, pretty unequivocally. Um. But like
- 27:39Speaker 1: all things, it's it's in moderation is the key. Uh.
- 27:43Speaker 1: In the nineteen thirties and forties and into the fifties,
- 27:46Speaker 1: they had X ray machines at shoe stores. Oh yeah,
- 27:50Speaker 1: I can extra your feet to get a better fit,
- 27:53Speaker 1: and um, they didn't realize at the time that they
- 27:55Speaker 1: were X raying people way way too much. Yeah, talkative
- 27:58Speaker 1: kids in class. They just shoot him with an X
- 28:00Speaker 1: ray and they probably did I've got you like twice. Well,
- 28:05Speaker 1: now I would believe that, like, hey, let's look at
- 28:06Speaker 1: his brain. There may be a mouse running around inside
- 28:09Speaker 1: of it. People in the thirties were dumb. Well, it's
- 28:13Speaker 1: basically radiation sickness. Um, it's a form of ionization or
- 28:17Speaker 1: ionizing radiation. So what can happen? Like, if just normal
- 28:21Speaker 1: light hits an atom, is no big deal. But when
- 28:24Speaker 1: an X ray hits an atom, it knocks electrons off
- 28:27Speaker 1: of it creates an ion, which is an electrically charged atom,
- 28:31Speaker 1: and basically anything from uh, cellular death to mutation can
- 28:36Speaker 1: happen at that point, and mutation can spread and it
- 28:39Speaker 1: can cause cancer. Right because stable atoms are neutral, right,
- 28:43Speaker 1: because they have an equal number of protons and electrons.
- 28:46Speaker 1: You lose an electron, all of a sudden you have
- 28:48Speaker 1: a positively charged ion and that negatively charged electron running
- 28:53Speaker 1: around and it just causes trouble. And you said light.
- 28:56Speaker 1: Visible light can be absorbed and it's no big deal
- 28:59Speaker 1: because visible light is exists on a wavelength that's about
- 29:03Speaker 1: in tune with the soft tissues of our body, right,
- 29:06Speaker 1: so we know how to absorb it and it makes
- 29:08Speaker 1: us tan and that's cool, right. But um, with these
- 29:12Speaker 1: ionized atoms, these positively charged atoms like going around in
- 29:16Speaker 1: your body, it can cause a lot of problems, like
- 29:20Speaker 1: mutations like cancer. Right, yeah, I mean if you break
- 29:23Speaker 1: that DNA chain, that's not good. No, it is, And
- 29:26Speaker 1: one of the results is the d The DNA can
- 29:29Speaker 1: basically lose its ability to regulate itself and the cell
- 29:34Speaker 1: replicates more frequently than it should, and all of a sudden,
- 29:37Speaker 1: you have a tumor on your hands and that can spread.
- 29:40Speaker 1: It can also be a problem if that DNA break
- 29:44Speaker 1: occurs in utero, because then that can lead to birth defects,
- 29:48Speaker 1: which is why pregnant women shouldn't get X rays UM,
- 29:51Speaker 1: and it can also just lead to plain old cellular death.
- 29:54Speaker 1: If you have cellular death and the tissues that UM
- 29:57Speaker 1: are made up by those cells break down, uh, you
- 30:01Speaker 1: have a problem on your hands with that as well.
- 30:03Speaker 1: So here's the deal. We get exposed to radiation every
- 30:06Speaker 1: day just walking around on the planet. Um. It depends
- 30:10Speaker 1: on where you live. But every year, um, the average
- 30:14Speaker 1: person is going to be exposed to anywhere from one
- 30:16Speaker 1: to four. Uh. It's measured in millisieverts per year UM.
- 30:21Speaker 1: Like I said, depending on where you are. I think
- 30:23Speaker 1: in higher elevations it's less then at sea level. So
- 30:27Speaker 1: if you live in Denver, Colorado, you're gonna be exposed
- 30:29Speaker 1: to less well yeah, because you're higher up in the
- 30:33Speaker 1: atmosphere and that makes a difference. Exactly, you have less protection,
- 30:37Speaker 1: right yeah. So um, you know what they what they
- 30:40Speaker 1: want to do medically speaking, they want to use, or
- 30:44Speaker 1: they're supposed to use the minimum amount to achieve the
- 30:48Speaker 1: pictures you need. It's not like the old days where
- 30:50Speaker 1: they're just like let's X rays. Yeah, Like let's do
- 30:53Speaker 1: the minimum amount we need to get the information that
- 30:56Speaker 1: we need. A CT scan can can get your you know,
- 31:00Speaker 1: you lay down in the tube and it rotates around
- 31:02Speaker 1: you and your whole body can be photographed in less
- 31:04Speaker 1: than five seconds these days. But um, you know there
- 31:08Speaker 1: are concerns if you get too many X rays still, Uh,
- 31:12Speaker 1: like a dental panorama, I think, would I say one
- 31:15Speaker 1: to four millisy verts per year and it's cumulative to
- 31:19Speaker 1: you should yeah, Like it's not. It's not like you
- 31:21Speaker 1: get one and then you know, eight months later you
- 31:25Speaker 1: get another one in that first one went away, Like
- 31:27Speaker 1: it accumulates over the course of a year. Yeah. So
- 31:30Speaker 1: here's just a few examples of how much radiation you're
- 31:33Speaker 1: being exposed to with X rays. Um, a dental panorama
- 31:37Speaker 1: is going to be point zero one millisy verts, so
- 31:39Speaker 1: not very much. Um, Like two chest X rays might
- 31:43Speaker 1: be point one mam or grammas around point four. Uh,
- 31:47Speaker 1: your pelvis point six, your back upper back maybe one
- 31:51Speaker 1: point zero. Uh. I wonder why because there's maybe, yeah,
- 31:58Speaker 1: maybe you have to do with exposure to Uh. Yeah
- 32:01Speaker 1: that makes sense. I got a ton of bone in
- 32:04Speaker 1: my upper back. A full CT scan, it depends on
- 32:08Speaker 1: what you are, Um, it depends on what you're X raying.
- 32:12Speaker 1: But a CT scan is obviously more like an abdominal
- 32:16Speaker 1: or pelvis c T CT scan could be as many
- 32:19Speaker 1: as ten millis everts, So that's like up to two
- 32:22Speaker 1: or three years worth of radiation in a single CT scan,
- 32:25Speaker 1: which can be problematic, which is why they don't say
- 32:28Speaker 1: get in the CT machine like every other week. Um,
- 32:32Speaker 1: but you know some of the reasons you might if
- 32:34Speaker 1: you had a traumatic injury, they're gonna X ray you
- 32:37Speaker 1: a lot of times for disease confirmation. They'll use an
- 32:40Speaker 1: X ray machine. Uh, during surgery as a visual guide,
- 32:44Speaker 1: Like if you do endoscopic surgery, the surgeons actually needs
- 32:48Speaker 1: to look at something, so sometimes the X rays for
- 32:52Speaker 1: that or to monitor your healing process. Um, you know,
- 32:55Speaker 1: when you break a bone, it's not just that first
- 32:57Speaker 1: X ray. You're gonna keep getting them to see how
- 32:59Speaker 1: your healing up. Right out of the Siemens video, huh no,
- 33:04Speaker 1: they isn't okay, I don't think so. I mean I
- 33:07Speaker 1: looked at so much stuff together, cumulative research. So uh,
- 33:13Speaker 1: I did a brain stuff on siverts and how many
- 33:15Speaker 1: we can take and uh yeah, it's it's kind of
- 33:19Speaker 1: like it's a little alarming how much radiation we're expected
- 33:22Speaker 1: to People who fly a lot too are exposed to
- 33:24Speaker 1: tons of radiation because you're again higher up in the atmosphere,
- 33:27Speaker 1: so you're less protected by the atmosphere. Speaking of flying,
- 33:31Speaker 1: of course, baggage that is X rayed. The food industries
- 33:35Speaker 1: is X rays a lot um. Archaeologists use it if
- 33:38Speaker 1: they don't want to like destroy an object and they
- 33:41Speaker 1: want to see what's inside, or earth sciences they'll use
- 33:44Speaker 1: X rays for rocks to see what kind of mineral composition.
- 33:47Speaker 1: So there's all sorts of applications. It's not just medical.
- 33:50Speaker 1: Um space. Yeah, X ray telescopes out on on satellites
- 33:56Speaker 1: apparently you can see a lot um. You can see
- 33:58Speaker 1: things you can't detect from an earthbound telescope because X
- 34:02Speaker 1: rays are absorbed by our atmospheres. He can't like shoot
- 34:05Speaker 1: it into space like that. So this article makes a
- 34:08Speaker 1: pretty good point if you ask me, it says like, yes,
- 34:11Speaker 1: X rays are like are bad for you, and you
- 34:15Speaker 1: should use them with care and caution. And one one
- 34:19Speaker 1: good point is to always ask if there's an alternative
- 34:22Speaker 1: to an X ray, just to basically say, hey, doc
- 34:25Speaker 1: or Dennis, slow your role. Let's is there another way
- 34:28Speaker 1: we can get this information without an X ray. I
- 34:30Speaker 1: know it's the easiest, But what are the alternatives? But
- 34:34Speaker 1: then the article makes the point like it's still safer
- 34:37Speaker 1: than the ultimate alternative, the thing that X rays replaced,
- 34:40Speaker 1: which was exploratory surgery. Yeah, back in the day, if
- 34:43Speaker 1: you they thought you had cancer, they would cut you
- 34:45Speaker 1: open and see. And this is definitely better than that
- 34:48Speaker 1: or broken bone. Imagine getting that arm cut open just
- 34:51Speaker 1: to see how it's doing. They're like, no, it's not broken, right,
- 34:57Speaker 1: And we haven't invented anesthetic yet. So good luck with
- 35:00Speaker 1: your dentist, by the way, because um, I always get
- 35:04Speaker 1: the feeling that the dentists are like, no, your insurance
- 35:07Speaker 1: allows us to build for so many per years, he said,
- 35:09Speaker 1: that's how many you are going to get. These X
- 35:11Speaker 1: rays are putting my kid through college. Yeah. Uh, you
- 35:14Speaker 1: got anything else on X rays? That was a fine
- 35:16Speaker 1: amount of stuff. I'm feeling good about it. You feel
- 35:19Speaker 1: good about this one, sure too? Yeah. Uh. If you
- 35:22Speaker 1: want to know more about X rays, you can check
- 35:24Speaker 1: out this really informative article on how stuff works dot com.
- 35:27Speaker 1: It's got some great diagrams that explain a lot of
- 35:30Speaker 1: the stuff we were saying visually. Uh, And you can
- 35:33Speaker 1: type x ray into the search part how stuff works
- 35:35Speaker 1: and it will bring that up. Since I said search
- 35:37Speaker 1: parts time for listener mail. Uh this is from my
- 35:42Speaker 1: buddy Poppy and Vancouver. Uh stuff you shouldn't listener to.
- 35:45Speaker 1: That meant while I was there, and um, Poppy as
- 35:49Speaker 1: this to say he's got a pretty cool job. He
- 35:51Speaker 1: listened to the PTSD show and wanted to write in
- 35:53Speaker 1: about another option that he works with. He's a registered
- 35:56Speaker 1: acupuncturist in Vancouver with special training and AMMA and addictions.
- 36:01Speaker 1: He's a program called neurotrophic stimulation Therapy NTSD. In a
- 36:05Speaker 1: large part of the program uses ear acupuncture and electro
- 36:09Speaker 1: acupuncture to promote neuroplasticity in the brain. He says, you
- 36:13Speaker 1: can't necessarily directly fix the brain, but you can stimulate
- 36:16Speaker 1: the ear nerves will help the brain reregulate certain functionality
- 36:21Speaker 1: so it can heal itself. He's been treating trauma and
- 36:24Speaker 1: PTSD patients for several years and the evidence for his
- 36:27Speaker 1: efficacy is high. It can be done with acupuncture needles
- 36:30Speaker 1: alone or in combination with a mild electrical stimulation. UM.
- 36:34Speaker 1: Remember we talked about UM. Transcranial electromagnation. Yeah, transdermal cranial stimulation.
- 36:41Speaker 1: He says that's one of the things that he's also
- 36:44Speaker 1: using to treat PTSD, which is pretty cool, and he
- 36:47Speaker 1: said it makes cognitive behavioral therapies so much easier to
- 36:50Speaker 1: introduce because it promotes neuroplasticity and the results help a
- 36:53Speaker 1: PTSD suffer to be more open to and able to
- 36:56Speaker 1: receive positive social programming. So he has a program we
- 37:00Speaker 1: want to promote. If you want to see all the
- 37:02Speaker 1: components in action in this program, you can visit Last
- 37:05Speaker 1: Door Recovery Society at last door dot org slash nt
- 37:09Speaker 1: s T, or you can donate funds to help purchase
- 37:13Speaker 1: a brain scanner so that they can scientifically measure the
- 37:16Speaker 1: results of the program, which would really help show the
- 37:19Speaker 1: validity of the therapies. And if you're interested in helping
- 37:22Speaker 1: out Poppies, cause there because he's really big on treating
- 37:26Speaker 1: veterans in Canada. In the US, um I shortened as
- 37:29Speaker 1: a little U R L too bitley b I T
- 37:32Speaker 1: dot L Y slash one one y n l o
- 37:37Speaker 1: Q and that is from Poppy and he says not
- 37:41Speaker 1: misstay thanks a lot, Poppy. Is it poppy with the
- 37:44Speaker 1: O P O P P I nice? Uh if you
- 37:47Speaker 1: want to get in touch with us, you can tweet
- 37:50Speaker 1: to us at s y s K podcast. You can
- 37:53Speaker 1: join us on Facebook dot com, slash stuff you Should Know.
- 37:56Speaker 1: You can send us an email to Stuff Podcast to
- 37:59Speaker 1: how Stuff workstt com. That's right, uh and as always,
- 38:02Speaker 1: joined us at home on the web, Stuff you Should
- 38:04Speaker 1: Know dot com. For more on this and thousands of
- 38:11Speaker 1: other topics, visit how Stuff Works dot com