Boomerangs: Magic Sticks of Physics


Josh: Josh Clark

Chuck: Charles W. "Chuck" Bryant

Vo: Voiceover Speaker

Vo: Welcome to Stuff You Should Know from HowStuffWorks.com.

[MUSIC]

Josh: Hey, and welcome to the podcast. I'm Josh Clark, there's Charles W. "Chuck" Bryant, and Noel is with us today.

Chuck: Guess producing.

Josh: Yeah, which makes it super special Stuff You Should Know.

Chuck: A more hirsute Stuff You Should Know.

Josh: Yeah.

Chuck: That's right. Although Noel did get a haircut.

Josh: I know. He looks like a buddy of mine from elementary school.

Chuck: Your elementary school friend had a full beard. [LAUGHS]

Josh: No. If he took away the beard, it would be like any number of my friends from elementary school.

Chuck: Yeah, there was always that one guy that had the early, early facial hair.

Josh: Oh yeah.

Chuck: You know Jim Issa?

Josh: Man, I'll bet that kid was born with a beard.

Chuck: You know, Middle Eastern. He sort of had a little mustache from like the seventh grade.

Josh: I had a friend named Ron in elementary school. Man, he had like a deep voice, a moustache and everything. It may have been fourth or fifth grade.

Chuck: Now he sells stereos.

Josh: Yeah. So, obviously we are talking boomerangs, Chuck.

Chuck: That's right.

Josh: And if you associate boomerangs with Australia, there's actually a pretty good reason for that. It turns out that boomerangs-you think of a boomerang, which is kind of like a crescent-shaped stick that your throw and it just comes back to you eventually and you catch it and you look at your friends and say, "Pretty cool, huh?"

Chuck: Yeah, they're like, "How do you do that?"

Josh: That was, most people think, perfected by Aborigines in Australia.

Chuck: That's right. If you want to go back even further, there's a couple of types of boomerangs-well, there's many types of boomerangs, but two main categories are the ones that returns to you, that you play with, and the one that you go out and try and kill animals with that does not return to you. I call those the sad boomerangs.

Josh: Some people call them rabbit sticks.

Chuck: Rabbit, oh no.

Josh: I know, isn't that mean? But if you want to learn how to make one yourself, go to survival skills, the website.

Chuck: The hunting boomerang.

Josh: It's actually, it's pretty cool. This guy, he shows you step by step how to make a boomerang-Natural Skills, I'm sorry.

Chuck: Natural Skills.

Josh: He just goes out in the woods and finds like a kind of roughly boomerang-shaped stick.

Chuck: Yeah.

Josh: And then hews it into a functioning non-returning boomerang. It's pretty awesome.

Chuck: Well, and that's what people theorized, is how the boomerang came about back in Tuk-Tuk's day, they would eventually learn to take a club and beat an animal on the head and then maybe one of Tuk-Tuk's friends was smart enough to say, "Hey maybe if I can throw this at the animal from a distance, I won't scare them away."

Josh: Or, "That animal is faster than I can, but I can throw a stick faster than that animal can run, let me hit it in the head with a stick."

Chuck: That's right. And so, over time, just like any early tool evolution, I guess, you would find sticks that flew better and further and further. Eventually they sort of took the shape of a boomerang because of its unique flying properties.

Josh: Yeah, they figured out that a curved stick you can aim it more easily and it will fly longer, so they started selecting for those kind of sticks and then they started making those sticks themselves, like somebody from the Natural Skills website would.

Chuck: Yeah, the design of the two different branches made it more stable.

Josh: Yeah, and we'll get into the mind-bending physics behind a boomerang. Boomerangs, frankly, are magic sticks of physics.

Chuck: They are?

Josh: They're almost, it's almost impossible to understand them, like what's going on, but we are going to do our best to understand it. With a non-returning boomerang it's kind of straightforward. It's the returning boomerang, that they say the Aboriginal Australians were the first to invent, that is really difficult to grasp the physics behind.

Chuck: Yeah, and the oldest non-returning boomerang they found in Poland from about 20,000 years ago.

Josh: Yeah, that was surprising to me.

Chuck: What that that was that far ago?

Josh: No, that it was in Poland.

Chuck: Oh. [LAUGHS]

Josh: Because I think of like boomerangs exclusively associated with Oceania, not Poland.

Chuck: Yeah, they were found in Native American tribes, too, and stuff kind of all over the world. So Australian Aborigines used something called a kylie exclusively for hunting at first, and they think-and this is, I think, the neatest thing, because you certainly can't find this out factually. But they think that eventually they stumbled upon one that kind of came back and they thought it was fun, so they started throwing returning boomerangs, as just to get their kicks.

Josh: Just for kicks, because a returning boomerang you can't use for hunting.

Chuck: Well, no.

Josh: If you throw a returning boomerang-

Chuck: It's going to hit an animal.

Josh: Well, if you hit the animal, it's not going to return back to you. That's not real, that's in just cartoons, everybody. That's why there's two types. There's ones that you brain an animal with and there's another that you just throw around to impress your friends.

Chuck: That's right.

Josh: Apparently, though, the Aboriginal Australians figured out how to use returning boomerangs to hunt. They would put some nets up in trees.

Chuck: Oh yeah.

Josh: They would throw the boomerang, the returning boomerang, and then whoever was best at making like an eagle or hawk's call would make that call and it would scare all the birds because they would see this thing flying, hear a hawk's call, and they'd fly into the nets, and the Aborigines would eat them.

Chuck: Not a bad idea.

Josh: So that's pretty much the history of boomerangs.

Chuck: Yeah. You know, no one owns a patent on the boomerang. There are many kinds of boomerangs that people have patented, of course, but the original boomerang was just hey, this was something we just figured out on our own.

Josh: It's like DNA.

Chuck: Yeah, yeah. Sort of.

Josh: It belongs to the ages.

Chuck: Okay.

Josh: It belongs to the universe.

Chuck: So your returning boomerang is going to be a little lighter, obviously, because you're not trying to kill a rabbit.

Josh: It's just for showing off.

Chuck: Yeah. And I've even-you know, they have the little Nerf versions for kids. I had one of those when I was a kid, the little three-pronged boomerang.

Josh: Yeah.

Chuck: Those are kind of fun, but if you look at videos of the real deal-like large, three-foot, wooden boomerangs, it's pretty impressive to see. It's a tough thing to do; you don't just go out there on your first try and get it to fly back to you.

Josh: No, and there's actually like boomerang teams around the world.

Chuck: Yeah, U.S. Boomerang Team.

Josh: Yeah.

Chuck: Unless you're a wunderkind, of course, or a natural.

Josh: Where you do it on your first time?

Chuck: Yeah, I'm sure it's happened before.

Josh: Yeah, maybe.

Chuck: This made me want to get a boomerang, by the way.

Josh: Did it? Are you going to?

Chuck: I don't know, maybe. It depends on how much they are. [LAUGHS]

Josh: Are you going to start a Stuff You Should Know boomerang team?

Chuck: What I'm hoping is a fan makes handcrafted boomerangs and sends us one.

Josh: Oh yeah. I hadn't thought about that. I'll bet we have at least one boomerang maker, listener.

Chuck: So send us two.

Josh: Yeah, nice. Thanks, Chuck.

Chuck: That way we can go out and perform a little two-man boomerang-

Josh: Oh yeah. Maybe we can like cross them and everything.

Chuck: Sure.

Josh: That would be cool.

Chuck: Get our act down.

Josh: So again, the non-returning boomerangs are pretty straightforward. It's the returning boomerangs that are lighter and they are made to be more aerodynamic. The proper way to throw a returning boomerang is to hold it at a vertical angle. Hold it up and down, right? Which is weird because if you ever see somebody throw a boomerang, when it comes back it's horizontal.

Chuck: Yeah.

Josh: It is horizontally oriented.

Chuck: Yeah, it kind of just lands very softly like a helicopter.

Josh: Right. The thing is, it goes from upright to horizontal, in the midst of this path, and it comes back to you. If you stop and think about it, that makes zero sense whatsoever.

Chuck: Yeah.

Josh: A non-returning boomerang certainly doesn't do either of those things. It's just the returning boomerang. The whole reason behind this is because of the design of the returning boomerang. It's basically a two-pronged propeller that is not attached to anything, that thanks to the force you give it and its rotation and a whole other bunch of stuff that we'll get into, it leans to-it falls to the left, turns clockwise and comes back to you.

Chuck: That's if you're a right-handed thrower.

Josh: Yes.

Chuck: With a right-handed boomerang.

Josh: If you're a left-handed person, you have to have a left-handed boomerang. It's a mirror image of the right-handed boomerang. If you try to throw a right-handed boomerang with your left hand, it's not going to work out so well.

Chuck: I bet there's one person out there that's like, "Oh."

Josh: I'll bet too.

Chuck: "I had no idea."

Josh: So, we are going to muster up our courage and get into the physics of the boomerang, right after this.

[MUSIC]

Chuck: Josh, I got a little story for you. The other day I hopped in my one-horse open sleigh and I cracked the whip and I headed down to my local post office, and I couldn't find any parking for my reindeer because all the grumpy people there are trying to mail holiday packages.

Josh: Yeah, it's pretty awful, Chuck. I have a solution for you the next time you get in your sleigh.

Chuck: Oh yeah.

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Chuck: Wow, that sounds like your saying I can avoid all of the hassle of going to the post office, during the busy holiday season, by using Stamps.com.

Josh: That is precisely right, Chuck, because everything you would do at the post office, you can do right from your desk with Stamps.com. You can buy and print official U.S. postage using your own computer, your own printer. You can print postage for any letter or package, the instant you need it, and then the mail carrier picks it up. It's so easy and so convenient.

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Josh: Yep, so don't wait. Go to Stamps.com before you do anything else, click on the microphone at the top of the homepage and type in STUFF. That's Stamps.com, enter STUFF.

[MUSIC]

Josh: All right, Chuck.

Chuck: Here we go.

Josh: Yes. Here we go.

Chuck: All right. So I guess the first thing we should talk about is a little bit about just the physical design of the boomerang itself. The wings are slightly tilted so it creates what's called an airfoil, just like an airplane wing. You look out your plane window there and you're sitting on the wing, you're going to notice that the top of it is rounded and the bottom of it is flat.

Josh: Uh-huh.

Chuck: And that is going to give a plane lift and a boomerang lift.

Josh: Right. The air going over the top of the wing, because it's curved in like a teardrop shape, it picks up speed. The air speed is increased, which means the air pressure is also increased. Beneath the wing, it's flat. The air is just going through like it's whatever, but the air pressure is higher. So you have lower air pressure at the top, higher pressure at the bottom-that means that you have lift.

Chuck: I believe that is Bernoulli's principle.

Josh: Is it?

Chuck: I think so.

Josh: Showoff.

Chuck: No, not really.

Josh: So, that's the whole thing behind both airplane wings, like you said, and boomerang wings, because again, if you really kind of want to start to understand boomerangs, first of all, do more research than just listening to this podcast.

Chuck: Sure.

Josh: But secondly, you have to think of the boomerang as basically two airplane wings facing the opposite direction, connected together. Okay?

Chuck: That's right.

Josh: And that forms essentially a propeller.

Chuck: Yeah, and a propeller is-well, it's basically, if you think about a boomerang, it has an axis just like a propeller does, but the axis isn't there. Does that make sense?

Josh: Yeah.

Chuck: It's invisible.

Josh: Yes.

Chuck: The propeller is connected to something because it has to lift-the helicopter propeller because it has to lift the helicopter. Or if it's in the front of a plane, it's going to pull that plane forward and up, which is sort of a key we will get to in a second.

Josh: Yes.

Chuck: But it's the same principle, but a boomerang just has an invisible axis, let's say.

Josh: Okay, so it does, and it's very important because at that axis, which you can just imagine is in the center of the boomerang, where the two wings come together, that's the axis of rotation that the boomerang has, its spin.

Chuck: Yeah, and this article does a good job of pointing out that, you would think then, if you just turned it completely horizontally like a Frisbee, it would act like a helicopter propeller and just go up.

Josh: Yeah, straight up.

Chuck: Or if you turned it completely vertically-

Josh: Which is how you're supposed to throw it.

Chuck: -it would just go side to side. But it doesn't do either one of those things.

Josh: No, it doesn't, and the reason why is because if you turn on an airplane propeller, or a helicopter propeller, or a rotor, it starts from a stationary positon and just starts spinning.

Chuck: Exactly.

Josh: The boomerang doesn't start from a stationary position, it starts spinning along that central axis and it's also thrown.

Chuck: Yeah, it's got that forward momentum already.

Josh: Exactly, so it has now, because you threw this thing, you threw it and it started spinning around its own axis, but you also gave it that forward momentum, which is linear momentum, which means that it's now spinning around two axes.

Chuck: That's right.

Josh: Okay?

Chuck: Is this gyroscopic precession?

Josh: We are close, we are almost there. And we get there, Chuck, because of these two axes. So consider this. So the thing is just spinning around, you've just thrown it. It's upright. It's vertically oriented to the earth.

Chuck: Uh-huh.

Josh: And you throw it, and when you throw it, say it has a spin around that imaginary axis in the middle of the boomerang.

Chuck: Yeah, or at that point.

Josh: At like 20 kilometers an hour.

Chuck: Yeah. Because we are in Australia, so we're going to use kilometers.

Josh: Exactly. Plus also I read a Japanese paper on this, and that's what they used. And it makes sense. But you threw it, that energy your arm transferred to it when you threw the Frisbee, too, which gave it its linear momentum. Say that's making it move through space at 100 kilometers per hour, okay?

Chuck: That's right.

Josh: So as the thing is spinning, whatever blade is at the top of the spin is going in the direction that you threw it, right?

Chuck: Yeah.

Josh: And you threw it at 100 miles an hour, and it's spinning at 20 kilometers an hour. That means that that top blade is spinning at 120 kilometers an hour.

Chuck: You said miles, but yeah, we get it.

Josh: Okay.

Chuck: You were mixing miles with kilometers.

Josh: Yeah, I'm just barely hanging on here. The bottom one, though, is going in the opposite direction, so it's actually moving at 20 or 80 kilometers per hour. So the top is 120, the bottom one is working in the opposite direction, so it's going 80 kilometers per hour. But these things are attached to the same thing, so this difference actually creates a difference in air pressure to its vertical orientation.

Chuck: That's right.

Josh: Which create torque, which tilts it. Now, we have entered gyroscopic precession.

Chuck: Yeah, precession, I think I sort of said it like procession, but it's with an E.

Josh: Yeah, it's what gives earth's seasons, that wobble.

Chuck: The spin is another part of, a very important part because when you throw it-and we'll get into exactly how to throw it here in a bit, but you want to give it a good wrist snap to give it as much spin as possible. The spin is going to be determined, the rate of spin, by a few things: the length of the wings-if there are these huge wings, the spin isn't going to be as great-the angle that they're joined, and the amount of force applied by you, the thrower. Just like a gyroscope, which if we really wanted to torch ourselves we should do one on gyroscopes one day.

Josh: Man, that would be-melt. My brain would melt.

Chuck: Yeah. Just my brain doesn't process that stuff well. But like a gyroscope, it's going to have more stability the faster it spins, so that's why you want that good wrist snap.

Josh: Yeah, and the reason why it has more stability is because so that torque, that pressure that's being created by that difference in air pressure, that force is being pushed down, is actually stabilized throughout the spin of the boomerang, right?

Chuck: Yeah, like if you're going super fast on a bicycle and you take your hands off the handle bars, you're going to keep going straight. If you're going super slow, you're going to start wobbling around.

Josh: Right, exactly. The thing is that pressure, that force of torque is constant, so it eventually, because I think precession is, if you're throwing with your right hand, precession always comes on in a counterclockwise motion. The torque turns the boomerang to the sides, which is why it eventually comes back around to you horizontally. That's what lays it down, and it also brings it in an arc that forms a circular path that comes back to you.

Chuck: That's right.

Josh: It's all gyroscopic precession, and it's because the boomerang, this little simple stick that's basically one crescent-shaped piece of wood, turns into a gyroscope that turns on three axes all at once.

Chuck: Yeah, all in one throw.

Josh: And so it goes from stationary, being straight up and down, to spinning and curving around in an arc back to you at 100 kilometers an hour.

Chuck: Crazy.

Josh: All because you tossed it correctly.

Chuck: Yeah, and the design, I mean, there are many, many different designs of boomerangs. Like I said, they can have two wings, three, four-it can look like Krull and have blades attached to them, because there is something called the battle boomerang.

Josh: Yeah. Man, that seems dangerous.

Chuck: Yeah, it seems totally dangerous.

Josh: I'll bet you could find that at like a head shop somewhere, next to like a dragon pewter statue or something.

Chuck: They probably have a deal where you can buy them together for cheaper. Some of them have what's called turbulators, though, which can be little bumps and pits on top, which can increase the lift even more. I read an interview with one boomerang builder, and he was like you can't-I'm sure like Nerf can with their soft ones, but like a true, large, three-foot wooden boomerang, he said, "You can't computerize these and build them. They kind of need to be handcrafted and thrown and then tweaked and then thrown, until you get it just right."

Josh: I saw one of the U.S. Boomerang Team guys demonstrating on a video and he just put a rubber band on his to adjust it somewhat.

Chuck: Oh, that makes sense.

Josh: Yeah, because you know, if you have a ceiling fan or something like that, you can add weights or something to stabilize it. That kind of thing.

Chuck: Or when you get your tires installed in your car, they put those little lead weights to-what's it called?

Josh: Align it?

Chuck: Yeah, to align it.

Josh: Yeah.

Chuck: They put it on that machine and if it's wobbling, they'll add the little weights on the inner rim.

Josh: I didn't know that. I just thought there was a wizard in the back.

Chuck: You're always in the waiting room drinking coffee and reading-

Josh: Browsing their-

Chuck: -Popular Mechanics.

Josh: -pewter dragon statues.

Chuck: No, it's kind of cool actually-well, I think it's kind of cool, it's really kind of nerdy-to watch your tires get aligned.

Josh: Yeah.

Chuck: They put it on the machine and spin it, and it's really kind of just like this and they look at it, and if it's wobbling at all they know exactly where to tap on these little weights.

Josh: Nice. Because, yeah, you don't want your tires to be a gyroscope.

Chuck: No.

Josh: Not at all.

Check: You don't.

Josh: That makes for unsafe driving.

Chuck: So I guess we should, after this message break, teach you how to throw a boomerang.

[MUSIC]

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Josh: What?

Chuck: That light bulb above your head.

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Chuck: Man, every time it happens, it's really neat.

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[MUSIC]

Chuck: All right, you've got your boomerang, you're out in a field.

Josh: Uh-huh.

Chuck: Or on the beach. Beach is going to be tough because wind is one of the forces that are going to act on that boomerang. There are five forces.

Josh: I'm so nervous, man.

Chuck: The force of gravity, the force caused by that propeller motion, the force of your throw, the force caused by uneven speed of the wings, and then the wind. The guy that I watched throw one on YouTube said that he like to throw one with a slight breeze in his face.

Josh: Uh-huh.

Chuck: He said that it depends on the angle at which you're going to release it, though, depending on how the wind, and there's a lot of trial and error involved.

Josh: Yeah. Apparently you want wind. I couldn't figure out what the deal was with this, but it somehow helps the boomerang move. You have what's called an angle of attack, and that's basically how you orient yourself to the wind. If the wind is blowing in your face, you should turn and face-you don't want your shoulder now being hit by the wind, because that's 90 degrees.

Chuck: He turned a little bit to the right.

Josh: So probably about like 45 degrees, and that's what you throw to. So you're throwing at an angle to the direction the wind is coming at you from.

Chuck: Yeah, but this guy kind of worked it out, like he threw the-he kind of measured the wind, you know, did the old finger test.

Josh: Did he?

Chuck: Yeah. And he said, "I'm going to angle myself a little bit to the right and I'm going to throw it," and he said, "And it should land just in front of me." It went behind him and he was like, "Well, I was wrong. So I didn't have a good wind measurement, so let me angle it a bit more." And sure enough, the thing came right back to him.

Josh: Nice.

Chuck: So it all depends on what angle, against the wind, that you throw that thing.

Josh: Like Bob Seger says.

Chuck: Oh man. I can't stand that guy.

Josh: Really? Bob Seger?

Chuck: Yeah.

Josh: I don't have anything against him, honestly.

Chuck: Yeah?

Josh: Yeah.

Chuck: That "Old Time Rock and Roll" song, I turn that as soon as I hear those first piano keys.

Josh: Oh, that's his? Yeah, I hate that song, too. But overall, I think Bob Seger is okay. He seems fine. He is a working man.

Chuck: Yeah?

Josh: Yeah.

Chuck: "Turn the Page," baby [LAUGHS].

Josh: Oh yeah, I don't like that song, either. I guess I just like "Against the Wind."

Chuck: "Like a Rock"

Josh: Oh I hate that song.

Chuck: "Hollywood Nights"

Josh: That's a terrible song, too.

Chuck: You hate Bob Seger.

Josh: No, but I don't mind "Against the Wind." Surely there's other Bob Seger songs. Bob, get in touch with us and introduce me to your catalogue.

Chuck: That would be great if he was a listener, actually.

Josh: He's just got a single tear going down his check.

Chuck: All right, so where were we? You're going to hold the boomerang with the V, with the elbow pointing toward you and the V pointing out away from you.

Josh: And again, up and down; it's vertically oriented.

Chuck: Yeah, vertically oriented but at a slight tilt. You don't want it completely straight up and down.

Josh: But you're not throwing it horizontally like you would a Frisbee.

Chuck: No, you're not going get very far that way.

Josh: No, actually it does go up and then comes back down in a loop. It basically does-

Chuck: Oh, it will do something interesting [LAUGHS].

Josh: Yeah. The thing is, it's kind of dangerous, so you don't want to mess around with it.

Chuck: Yeah, I mean, we should point that out. These things are heavy and made of wood and they come-you know, you're throwing it hard.

Josh: Well, yeah, let's cut to the chase. Apparently when you throw a Frisbee, or a boomerang-which are virtually interchangeable in my mind, but they are really not.

Chuck: Not at all.

Josh: You want to keep your eye on it at all times. And if you ever lose sight of it, you don't look around for it. You need to go take cover. Cover your head and shout, "Heads up." And get everybody else to cover their heads, too, because that thing can come back and clock somebody.

Chuck: Yeah, and that's if you haven't thrown it right. When I have seen the correct boomerang toss, it lands like a helicopter-you know, straight up and down. Not completely straight up and down.

Josh: So sorry. What's the next step?

Chuck: All right, so you've got that V pointing away from you.

Josh: Pointing at you.

Chuck: No, no, no. You want the point facing towards you and the V facing away from you.

Josh: Okay, gotcha.

Chuck: And you want, it's super important, this part is-you want that flat side, remember we talked about the airfoil, you want the flat side facing out, so to your right if you're a right-handed thrower.

Josh: Gotcha.

Chuck: If you don't do that right then you're not going to have a good result.

Josh: Yeah. You would only probably tilt it to the left of the wind if you're left-handed, I would guess.

Chuck: I don't know about that.

Josh: Okay.

Chuck: I don't endorse that statement.

Josh: Okay.

Chuck: So you're going to hold it at the bottom of the wing, like they say a pinch grip. The guy in the video called his a little pistol grip, like with two fingers and a thumb. And you want to snap your wrist when you throw it, and he didn't throw it super hard.

Josh: Yeah.

Chuck: Like you don't have to really wing it.

Josh: Yeah. He didn't sound like Steffi Graf when he threw it or anything.

Chuck: Monica Seles, you mean?

Josh: I thought Steffi Graf did that, too. Was it Monica Seles as well known for that?

Chuck: Well, there's a lot of grunters, but Monica Seles was the "uh-ugh" every time she hit it.

Josh: That's who I meant, then.

Chuck: But she got stabbed, look what happened to her.

Josh: Oh gosh, I thought that was Steffi Graf, too.

Chuck: No.

Josh: Did you know Steffi Graf and Andre Agassi are married?

Chuck: Yeah.

Josh: Isn't that cute?

Chuck: It's adorable.

Josh: Okay.

Chuck: You know what would be funny is if their kids were terrible at tennis.

Josh: They just trip over their rackets, or whatever. Bob Seger is their coach.

Chuck: That's right. He's their badminton coach. All right, so you are snapping your wrist, you're throwing it basically like a baseball, at a little slight angle, and you're going to snap that wrist to give it a good spin. You throw it vertically, and hopefully it's going to go out and up and curve around and then land back down, fairly softly, somewhere close to where you are. And you don't want to try and catch it with your hand, like in a cartoon.

Josh: Well, you can, but you want to clap your hands together on it.

Chuck: Yeah, yeah. Don't try to catch it like a Frisbee.

Josh: No, but I think if you are a boomerang-throwing person, you are trying to catch each one.

Chuck: Oh yeah, yeah. Just not with one hand.

Josh: You don't do it one-handed, you clap it together. You trap it in between your two hands.

Chuck: Yeah, and if you're catching a Frisbee like that, then God help you.

Josh: Yeah, you're going to get laughed at. But it's safe too. It's just you don't really have to be worried about a Frisbee.

Chuck: It's super safe. I don't think I have anything else. Is that it?

Josh: Well, just one other thing. When I said that it's spinning around three axes, if you were impressed with that, prepare to have your mind blown even more. It's spinning around three axes to lay down flat from the torque; it's also spinning around an additional three axes to follow that arc in a giant circle and come back to you. So technically, a boomerang, when you throw it, is spinning on six different axes.

Chuck: From the point of release to the point of landing?

Josh: Yeah.

Chuck: Wow.

Josh: Isn't that neat?

Chuck: It's pretty neat.

Josh: Yeah, it's neat, and this is one of those things where people were throwing these things long before we knew anything about how they actually worked. People figured them out, and then science came along afterward and said, "Oh, this is how it works." But this stuff is so complex, it really kind of exposes that moment in science where you're like, "I kind of have to have faith in this, because I understand it so thinly that I just have to have faith that this is correct," and it's almost virtually the same thing as saying, "Well, there's the great wizard is the one who is moving it around in an invisible circle back to you because he wants you to prosper and not have to make a boomerang every time." Virtually the same thing, at this point, in my understanding.

Chuck: They are a great teaching tool, as well. I imagine if you're trying to teach physics and gyroscopic precession, then.

Josh: The problem is almost everybody I saw, except for the Japanese paper-I think it was titled "What Makes a Boomerang Come Back"-were just terrible at explaining it. They understood everything but they could not explain it in anything approaching layman's turns.

Chuck: You know, I read a Popular Science article, I think it was called "The Science of Boomerangs." It was pretty good.

Josh: I wish you would have sent it to me, because I've been agonizing over this for many, many, many, many hours.

Chuck: I just figured you had your Japanese sources and were good.

Josh: It was in English too.

Chuck: Well, of course it was. You don't read Japanese.

Josh: I don't read Japanese so good. If you want to know more about boomerangs, you can look up stuff all over the web, but why not start at our website HowStuffWorks.com. Just type that word in the search bar and it will bring it up. And since I said search bar, it's time for listener mail.

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Chuck: I'm just going to call this "I Split Atoms for a Living."

Josh: Nice.

Chuck: So you know we are on the wrong track already.

Josh: Or we are going to be corrected.

Chuck: Yeah, but he is very nice about it. "I spilt atoms for a living at a nuclear power plant, so I was really excited that you did a podcast on a nuclear science topic. You guys really did a great job actually of breaking down the topic and making it accessible to a wide audience, something I personally feel that organizations involved with nuclear technology tend to struggle with a little bit. Anyway, I'm writing in with a correction. You stated that nuclear fission reactions involved the electromagnetic force, while nuclear fusion reactions involve the strong nuclear force."

Josh: I remember saying that.

Chuck: "Both of these reactions actually get their energy from the same strong nuclear force. In both cases if you were to measure the mass of the material before the reaction and compare that to the material after the reaction, you would find that there is less because some of the strong nuclear force holding the atoms together was released as energy. The difference in the energy released pretty much comes down to how much of this mass was converted, divided by the mass of the atoms involved."

Josh: You see the thing is that makes total and complete sense, if you think about it.

Chuck: Sure.

Josh: That makes it irritating that we got it wrong.

Chuck: "Since atoms good for fusion are much lighter than the atoms good for fission, the reactions are a bit stronger. Reactions which involve the release of stored electromagnetic energy are actually all of the reactions that involve electrons, which includes chemical reactions, since this is a much weaker force; that's why there is such a huge energy difference between burning coal and burning nuclear energy, as you pointed out in the podcast. It's millions of times more potent. So thanks again, guys. Looking forward to the next one." And that is Jeffrey Hausaman. He is a reactor engineer in Zachary, Louisiana.

Josh: Thank you very much. What's his name again?

Chuck: Jeffrey

Josh: Jeffrey, appreciate that. We love hearing from experts in the field.

Chuck: Oh yeah.

Josh: If you are an expert in your field and want to correct us about something, or whatever, we want to hear from you. You can tweet to us @SYSKPodcast, and join us on Facebook.com/StuffYouShouldKnow, you can send us an email to Stuffpodcast@HowStuffWorks.com, and you can join us at our home on the web, StuffYouShouldKnow.com.

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Vo: For more on this and thousands of other topics, visit HowStuffWorks.com.

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