# The Bizarre Behavior of Rotating Bodies

Spinning objects have strange instabilities known as The Dzhanibekov Effect or Tennis Racket Theorem - this video offers an intuitive explanation.
References:
Prof. Terry Tao's Math Overflow Explanation: ve42.co/Tao
The Twisting Tennis Racket
Ashbaugh, M.S., Chicone, C.C. & Cushman, R.H. J Dyn Diff Equat (1991) 3: 67. doi.org/10.1007/BF01049489
Janibekov’s effect and the laws of mechanics
Petrov, A.G. & Volodin, S.E. Dokl. Phys. (2013) 58: 349. doi.org/10.1134/S102833581308...
Tumbling Asteroids
Prave et al. doi.org/10.1016/j.icarus.2004...
The Exact Computation of the Free Rigid Body Motion and Its Use in Splitting Methods
SIAM J. Sci. Comput., 30(4), 2084-2112
E. Celledoni, F. Fassò, N. Säfström, and A. Zanna
doi.org/10.1137/070704393
Animations by Ivy Tello and Isaac Frame
Special thanks to people who discussed this video with me:
Astronaut Don Pettit
Henry Reich of MinutePhysics
Grant Sanderson of 3blue1brown
Vert Dider (Russian JPvid channel)
Below is a further discussion by Henry Reich that I think helps summarize why axes 1 and 3 are generally stable while axis 2 is not:
In general, you might imagine that because the object can rotate in a bunch of different directions, the components of energy and momentum could be free to change while keeping the total momentum constant.
However, in the case of axis 1, the kinetic energy is the highest possible for a given angular momentum, and in the case of axis 3, the kinetic energy is the lowest possible for a given angular momentum (which can be easily shown from conservation of energy and momentum equations, and is also fairly intuitive from the fact that kinetic energy is proportional to velocity squared, while momentum is proportional to velocity - so in the case of axis 1, the smaller masses will have to be spinning faster for a given momentum, and will thus have more energy, and vice versa for axis 3 where all the masses are spinning: the energy will be lowest). In fact, this is a strict inequality - if the energy is highest possible, there are no other possible combinations of momenta other than L2=L3=0, and vice versa for if the energy is the lowest possible.
Because of this, in the case of axis 1 the energy is so high that there simply aren't any other possible combinations of angular momentum components L1, L2 and L3 - the object would have to lose energy in order to spin differently. And in the case of axis 3, the energy is so low that there likewise is no way for the object to be rotating other than purely around axis 3 - it would have to gain energy. However, there's no such constraint for axis 2, since the energy is somewhere in between the min and max possible. This, together with the centrifugal effects, means that the components of momentum DO change.

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2019/09/18

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コメント数 : 19K
@theCodyReeder 4 年 前
Oh! so thats why my liquid filled bullets keep tumbling!
Cody'sLab ummmm interesting
ay look it’s cody
Chances are, only an American would think of bullets...(my excuses if you're not American)
@randomly47 3 年 前
Bullets. Never heard that one coming.
@MrDickfish 3 年 前
Your bullets tumble because you ruined the Ballistic Co Efficient
@tonyfourpaws4511 11 ヶ月 前
I got in trouble at work today because I was tossing various objects and watching the flip. I tried to explain it to the boss but he wasn't having it. He fired me. Now I have more time to watch your videos!
@HyperVectra 9 ヶ月 前
You must not have explained it well. Sometimes people need to experience it themselves to truly understand the concept. If you cut his brake lines, his car should spin around the maximum angle of inertia.
@HyperVectra 8 ヶ月 前
@@nramrez Oh.. could you tell me then please?
Time to convert some of that inertia to getting a job 🙂
I have a feeling that when Feynman replied "No" to the question, it was because he considered even this "intuitive" explanation, not that intuitive for most non-physicists/engineers.
@jaydenwilson9522 5 ヶ月 前
what question?? im curious and havent read much feynman
@conormurphy341 5 ヶ月 前
@@jaydenwilson95225:51
@yommish 5 ヶ月 前
@@jaydenwilson9522 it’s in the video
@jaydenwilson9522 5 ヶ月 前
Its own Axis disrupts its harmonious dance... Which temporarily causes imbalance, but even then... It still seeks to return to a balanced state. And it always will return to that state... No matter how dysfunctional. - Jayden Wilsons "intuitive" explanation of the intermediate axis theorem.... guess I'm smarter? @@yommish
@yommish 5 ヶ月 前
@@jaydenwilson9522 wow, I guess you are smarter than Feynman
A colleague pointed me to this great video! I was fascinated to find that it also contained two additional facts about the great condensed matter physicists of the past century. 1) If you claim that any physical concept is not in the Landau-Lifshitz books, most probably you have not looked for it as carefully as you should. 2) It is really tough to beat Feynman's physical intuition on anything, even if he thought about it for less than half a minute.
@KiltedWeirdo 2 ヶ月 前
wow. the circle from the plane has collatz 3x+1 effect (its 4 squares is missing its internal circle). the tenis racket is a offset of mass in /2 settings. nice! I wonder. does this apply in quantum and subatomic environments?
How beautiful you explained one of the most counterintiuitive physics problems in an intuitive way.
@kevinc1956 8 ヶ月 前
Noticed this effect when idly flipping a hammer as a construction worker in the latter 1970s. Always wondered what the cause was, as with some practice I could flip the hammer so that it didn’t flip. Was never sure if it flipped because I imparted a spin. When I went to college in the 1980s and got an engineering degree, I don’t recall that this theorem ever came up in physics, math, or engineering classes. Thanks for the explanation!
@joedaly6887 3 年 前
As a carpenter for over fifty years I've recognized this behavior with flipping of a hammer because I early on decided to teach myself to juggle hammers. I tried to prevent the twist-flip with absolutely no success. It became clear there was more stability in working with the flip instead of against it. This explanation is such a relief! I thought it was a personal curse. Now I realize hammers are the perfect object to demonstrate this motion because they, unlike tennis rackets, have no symmetry about any axis!
@johnpossum556 3 年 前
You just got defective hammers.🤣
@joedaly6887 3 年 前
@@johnpossum556 additional evidence: rip claw configuration in hammers produce more consistent axial twisting.
@pmcgee003 3 年 前
Once again ball pein better than claw hammer. 😀 😉
@alsteiner7602 3 年 前
@@joedaly6887 that has been my experience flipping a straight claw for years--it never rotated about the intermediate axis. Very east to flip
Yeah. Same here. Carpenter. Hammer. Flipping.
Watching a mathematician do something physical and coordinated is almost as interesting as the great info provided.
It becomes more difficult to travel further in any one axis. Accelerating in one direction of rotation meets this criteria. The wingnut flips because the continuing rotation acts like an acceleration yet with an easy way to change axes from 0 g. The limit as a rational value goes to infinity becomes irrational in the same axis, every time. Nice video!
@bjbrooks 8 ヶ月 前
Quite simply one of the best, most fascinating videos I've ever seen. As a tennis player, it's always fascinated me how the racket appears stable when flipped in from a vertical starting position, yet twists in the air when flipped from a horizontal starting position. I've never found any explanation (though to be fair I've not looked), but happened across this from an answer on Quora. Watch the whole video - the implications discussed at the end are quite literally out of this world. Excellent, 10*
@Evan_Harsh 年 前
I had always wondered why a tennis racket could never flip straight, finally get an explanation! Thank you lol
New sub, thanks for the content. I found your video interesting, informative and entertaining. I experienced this many years ago when I was a carpenter stacking roofs. Showing off I would spin my rigging axe and catch it, it looks dangerous and quite impressive especially with the twist. In reality it is quite stable and predictable.
@rv6amark 3 年 前
I was a dynamicist in the aerospace industry for 43 years, and THAT is the BEST plain text explanation of this behavior I have ever seen! Fantastic!
@gregsmith1719 3 年 前
Wow! You have sold me! I'll watch it again!
@xccghvbno1063 3 年 前
Then you're probably the person to ask what are the odds that the plates shifting around could in fact change the Earth's moment of inertia to where it could possibly effect the crust in a dramatic way? Just curious not every day one has a chance to ask a question to an expert who's possibly even thought about the same But actually with the educational background to get through the weeds of the problem and Come up with a Realistic hypothesis even if it is just A rough mental outline
@danielhope2924 3 年 前
Was I watching this correctly to assume that if the frozen poles had enough elevated weight and then melted lowering that weights and even some of the water dissipating towards the equator, this could shift the moment of inertia ?
@xccghvbno1063 3 年 前
@@danielhope2924 very good point. Time For me to go research exactly how much ice is estimated to be Frozen.Thanks for the input
@3.k 3 年 前
@@danielhope2924 The poles are where the least mass is, on the spinning axis. So if their mass would be distributet all over spinning system, the spin should become even more stable, because the mass around the equator would become even more significant.
This was an incredibly clear and concise overview. Brilliantly done.
Thank you! This is an amazing explanation and I can finally see in my head how it works. I've never been able to follow the maths involved.
@wassenaat 4 ヶ月 前
always nice to see a video that does rigid-body dynamics more justice than my faculty
That was interesting and really intuitively explained. Thanks!
@fbilgrami 6 ヶ月 前
Well done, first time I have seen someone go through the trouble of showing a rotating frame of reference. How a rotating body sees the world around it and the centrifugal forces it experience.
@davidking2846 4 年 前
I've been flipping tennis rackets for years and never been able to get my head around this effect. Incredible.
@fxm5715 4 年 前
I always figured I was just giving it some spin around the long axis unintentionally, because I didn't have enough dexterity to do otherwise. Now I know better.
@naverilllang 4 年 前
I always assumed it had to due with imbalanced rotation compounded by air resistance. Which I guess was half right.
@timbeaton5045 4 年 前
@po_thiago 4 年 前
I've also been flipping tennis rackets for years, but never been able to get my head away from its path on its way down... ;(
@larryrich327 4 年 前
David King I always thought it was my skill that caused the flip I didn't know it was doing it on its own 😕
@revv45acp71 8 日 前
Very interesting and a great explanation! Thanks!
@dp6569 年 前
This is the best explanation, thanks Derek
@carolduvall111 9 ヶ月 前
Oh my you already got a list you are working on thanks for sharing your knowledge and a bit of fun
@jacobpoulton3547 11 ヶ月 前
I've watched this video like 5 times and the hook at the begging is so good I still watch the video the whole way through
This guy solves my problems, that I never had. He's simply awesome. 😍 I always learn alot from his every video ❤
@2false637 4 年 前
This is the content I subscribed for. Well done!
@winkil1 4 年 前
Agreed
that was intense ! it's been more than a year probably when I watched the video by the first time and I did not understand much. I'm glad that today I understand more. Thank yo so much for what you do. You are awesome !
@Kaldrin 年 前
So this is what happens whenever I flip the remote and it does a half spin
Yeah 😆
@redasylum 年 前
Thanks for the simple explanation.
Your video brings to mind Golf. Our hands and wrists have three axis as does all golf clubs. When it comes to swinging a club our rotating body is the centrifuge that swings the club on it centripetal path All golf clubs are designed to swing on an intermediate axis as they reaches the bottom of their arc at the ball. So if golfers were to permit all this to happen they all would be much happier. At age 75 I finally learned to simply fold my trail arm and swing my club and wow the difference it made in my game. Cheers
@CorwinAlexander 3 ヶ月 前
Thank you. I wondered why the intermediate axial theorem didn't appear to apply to the planet. Thank you for clearing this up.
"The goal of this video is to prove Feynman wrong." You have high ambitions, young man!
@caparroz1923 4 年 前
As soon as I heard him say that I came to see this comment. Was not disappointed. High ambitions, indeed.
@raykent3211 4 年 前
Very brave! Feynmann: so you're saying that loss of kinetic energy causes a change in rotational axis to that of maximum moment of inertia, when usually it just slows things down? Since when was inertia intuitive? My ref to surely you're joking.... great video, though.
@rubiks6 4 年 前
I think he was quite successful. Raspberries to Feynman.
@@raykent3211 Indeed, it all depends on what you call "intuitive". I think inertia is a step higher than what most people will find intuitive.
My first reaction was that it is quite rude to make such an attempt, if not actually heretical - Feynman being such a towering icon of scientific thinking. Then I thought 'Nah, Feynman would love it.' I was fairly comfortable with understanding this phenomenon, but I suddenly had a very nasty moment when the subject of the Earth doing the same was raised. It being a fluid filled object and everything - magnetic poles flipping as evidence. I'm glad he could assure us it would not. So, did he prove Feynman wrong? Because my brain still hurts.
@connorh1060 7 ヶ月 前
@Veratisium This is a great video. I wanted to ask (for clarification): in your disc rendering of the “intuitive explanation,” it seemed to be a requirement that the two smaller point masses were slightly off of the intermediate axis. If they were not, would this effect not occur?
Is it the case that in reality impossible to be perfectly balanced?
@Horizon16 年 前
So I am confused about one thing. At 8:24 it suggests that this rotational flip only occurs when it is bumped or not perfectly flat across the plane. So is it that if we flipped it with the shape whilst being perfectly flat, it will flip over its axis normally without the shape doing the rotational ship? (Note I might being using rotational flip wrong, but I think you get what I am trying to say.)
Flipping brilliant!
@memetoo1002 年 前
I see what you did there.
@CoyoteFeral 年 前
Man, these animations are always top notch.
@alvirahesc7436 2 年 前
"Babe, come over, im home alone" "No, babe, Im solvin a centuries old math problem."
@ragnarok7976 2 年 前
The problem: Where does she want to go for dinner.
@davidh1206 2 年 前
You’re dating the wrong person if this isn’t an acceptable alternative to dinner
@TheNebulon 2 年 前
He bumps her on the secondary axis to get her to turn around
@NickRanger 2 年 前
@@TheNebulon it's the 3rd axis we all want
@automateddude 6 ヶ月 前
Really good video!! Thanks, well explained!
@StodOneR 6 ヶ月 前
I noticed this 7 years ago or more when I was into butterfly knives , actually I'm not sure if it's related , but if u try to spin the butterfly knife so that the narrow part of the knife rotates it will try to open . When you spin it length wise so that longer bit is moving it will force the knife to open after a few rotations if u manage to spin it fast enough it might do it a few times too
@amanverma-pu4fh 5 ヶ月 前
Am I correct - When rotated about intermediate axis ,the body tries to rotate it into maximum MOI axis hence we se Dzhenibekof effect as it's resultant....?
Thank u veritasium, very nicely explained 👌
I use this property of rotation in fire dance and never once thought about why it works. So cool!
*Russian Cosmonaut spins a wingnut in space:* _"TELL NO ONE OF THIS!"_
@rdreese84 4 年 前
That's how the Russians do.
@axiolot5857 4 年 前
@@rdreese84 Aaaah those russians
i seriously thought he was gonna use it somehow as a kinetic superweapon, but the earth turning upside down? You really think the US is gonna crap their pants if you can manage to turn the earth around? That's ridiculous
@clipsedrag13 4 年 前
@@silverhawkroman oh no!!! Everything is exactly the same!
@NicoKupfer 4 年 前
@@silverhawkroman Komrad Androvsky, vee kannot tell ze Hamerikans!
And this is why I love statics and and super excited to take dynamics
Noticed this years ago while throwing knives. Never understood it. Thanks for the video!
@CarlosReche 年 前
Hi, Derek! Thanks for bringing this subject to light. Let me get this straight. There are infinite axis by which you can spin an object, right? When you mention the object's "three principal axis", I think there are only two that you can clearly point it out: the ones with the greatest and the smallest moments of inertia. All other axis of rotation (infinite possibilities) would result to be in an intermediate moment of inertia. Is that right? So, here is a first conclusion: the stability of a rotating body is as higher as it is close to one of those two main axis (with greatest or smallest moments of inertia). Any rotation in an axis that has the slightest difference from these two would result to be an unstable one, and the body would flip after some time doing more or less spinnings (depending on how close it is to one of those stable axis). Am I correct to think of it this way? And, if so, here is another thought: when spinning the tennis racket by hand, we problably cannot reach the precision to do it exactly in one of those two main axis. And maybe it would flip if we gave it enough time to make a lot of spinnings. Which brings me to this: thinking the Earth as a body in constant changes (we have a lot of heat and pressure underneath our feet, evidenced by volcanic eruptions and earthquakes, not to mention external factors that might ruin any stable movement), what are the odds that our planet is really rotating in a stable axis? It makes me wonder, since there are a lot of cultures that talk about cataclysmic events that occur from time to time. And we have a bunch of evidences of it. But let's leave this conversation for another time. For now, for those who is interested (and also the skepticals), just reasearch about a book called "The Adam and Eve Story" and ask yourselves why it has been classified by the CIA in the 1960's, and has not been fully declassified by the Freedom of Information Act. I don't mean to be conspiratorial, but to me it's clear that this knowledge has been around for some time (like "always"), and is held by only a group of people.
@casst8291 9 ヶ月 前
Thank you! Felt like the video was very good until that last part where he breezily swept any alternative theories aside… more explanation needed on how the earth has a stable axis when magma, plates, and magnetic fields/ poles are in a constant state of flux!
I think he's lying, or someone is lying. the last part seems rushed to end the video. however we now know that there is a massive landmass under the ice
I could follow really good. Thank you!
@vsrini 年 前
Amazing ... great presentation
@llll-lk2mm 3 年 前
This explaination is beautiful when you're actually learning this stuff in school... keeps me wanting to know more. Thanks Veritasium!!!
@Tattootin 3 年 前
Never been a more deserving like to a comment on a video!
@llll-lk2mm 3 年 前
@@Tattootin :)
@mapk4655 3 年 前
I watch this as a break from stupid school work.
@jamessmith2622 3 年 前
@@llll-lk2mm %ï
@RitaMaru11 3 年 前
@@mapk4655 Good
I had seen a video on this subject awhile back and today I heard something about it and it turned on the lightbulb. I searched for a video of this happening and wrote in the comments: "I know why they do this, and it is a lot more simple than it looks!! To figure it out, all you have to do it watch the ending half of this when the handle spins slowly enough that you can play in slow motion and see the moment of change. It is a balance issue from material being removed to add in a set screw location for the handle. That small imbalance is enough to cause the flip every few rotations due to build up of imbalance. The handle part of the T handle doesn't play a role in inducing the "dancing" effect." Then realized it wasn't even a science channel and wanted to put this somewhere that others would read it instead of readers just being awe struck with the video alone and ignoring the how and what is going on.
Great explanation! Tks
This is amazing thank you!!
@fredrik241 年 前
Thanks this is super interesting. It brings to mind the recent discoveries of the massive blobs of higher density that's been found inside the earth. Its thought that these have higher density than other parts and if you look at some 3d maps you'll see that they support these rotation theories as the blobs are centered along earths 'mid riff' so could possibly be the factor deciding earths orientation.
@davis4555 年 前
Like the stability-bar on top of the top rotor of an RC helicopter.
My question is if the 'screw thing' at the beginning of the video was flipping again and again so wasn't it able to decide weather which is the highest moment of inertia position? If it could not atain highest moment of inertia at once then can earth also behave same by flipping again and again? Looking for a reasonable reply
@billdecat855 4 年 前
So the next time someone calls me "a flipping wingnut" I'll know why.
@energy_waves 4 年 前
Gemini
@mryu1995 4 年 前
Pff you are such a wingnut
@billdecat855 4 年 前
@@mryu1995 lmao, well played
@Bibibosh 4 年 前
Bill DeCat why?
@Bibibosh 4 年 前
Why is a wing nut an insult? I’
What about plate tectonics? As the crust is dragged under, and redistributed is there a chance that the maximum moment of inertia of the could be changed by this redistribution?
My thought as well.
That Is remarkable. What an amazing phenomenon. This is big.
Part of why I like your channel: around 4:55 you just casually drop that the paper is wrong, when in academia you would have had to go through peer review to publish your claim that the authors are wrong.
Nice video! You should consider doing a video dedicated to why we have or think we have magnetic pole shifts on the earth
Why isn't the explanation for the intermediate (y)-axis in 8:28 not equally valid for the x-axis. A small inclination from it should give the same periodically movement in my view, the only difference is that now the mass ratio between the main rotating mass and the tilted is different... Any ideas about that? I would appreciate it :D
@kodycook1505 4 年 前
I'm a carpenter and I'm constantly flipping my hammer while I'm not busy. I've wondered for the past 10 years (I became a carpenter in 2010) why is it the head and claws of my hammer flip flop when I flip my hammer head over handle. I thank you for this video!! I suffer from ADD/ADHD and I find myself pondering this very often (driving myself nuts over it). Thanks again for the answers!!!!
anxious minds made modern world possible
@Lugnut64052 4 年 前
First thing that occurred to me too. Been a carpenter for many years. Hammers will do that every time you flip them.
Yeah.....I understand ur struggle for all this year's I mean u could have done nothing about it..... If someone from MIT got this idea he would have derived it in few days because of their technology and advancements in maths n physics ..... I've gone through the same thing many times .....it takes time to solve problems .....unless i meet some expert on that topic and gain complete idea .....then i can solve it xd
@carlosbyrd4519 4 年 前
@Alexandre BrunetI hope so
@squarerootof2 4 年 前
@Compliment Thief Stop thieving.
@Veritasium. This was very enlightening. As an Electrical Engineer, I spend my time understanding the intangible. I’d really love to have a discussion about this topic and the history of Earth and global warming solely focused on the potentials of this science.
This video actually helped my tremendously in my physics class on angular momentum and torque lol
This reminds me a lot of the Wilberforce Pendulum, in which a bouncing up and down motion shifts to a rotating motion and back again, the KE phasing back and forth between the 2 modes. And there's a swinging mode also I think.
@theprior46 年 前
Fascinating and the maximum moment of inertia appears to apply to your consistent delivery of this long and very clear explanation. It didn't look like you were reading off an autocue either! Anyhow my brain hurts after all that! Maybe the phenomenon should be re-named the wibbly wobbly effect ie the instability of energy transfer. Or why figure skaters don't always fall over when they're spinning.
Possible movement charge in space occupation - try a symmetric wingnut, a long bolt with a wing and a disk with adjustable center pin - see if rotations increase before flipping Try in vacume of space to eliminate electrostatic influences. If you haven't already. End over end is highest combination of mass velocity = a pocket.
@qfmarsh64 2 年 前
As a kid, I would frequently watch my dad flipping the TV remote control in his hand and studying the inevitable half-turn in its flight pattern. He concluded that his wrist was subtly imparting spin. If he were alive today, his mind would probably be blown watching this video.
@llll-lk2mm 年 前
aww that's so cool
@dziltener 年 前
"He concluded that his wrist was subtly imparting spin." Well, as we've learned in your video, your dad was right
@roasty247 年 前
Cannot tell you how many hours I have done this with a TV remote too, trying to get a straight flip. Futile all along.
This physics trick puzzled me years ago when I was flipping a claw hammer. No matter what I did or how I flipped it it would not just flip with the claw on the right and the hammerhead on the left. It would end up that way but half way through the flip, the claw and hammer would switch sides. From what I understood of physics at the time, I assumed it was because either the claw or the hammer weighed more than the other and gravity interrupted the momentum. But this video proves me wrong. One thing I dont understand is that if its perfectly balanced, it shouldn't happen. I still think that Earths rotation has something to do with it.
@dziltener 年 前
@@siggyretburns7523 Yes that is correct, if it were perfectly balanced, it would not happen. But there is no such thing as "perfect" in practice.
Reminds me of the inertial roll coupling experienced by some aircrafts (F100, F102). This was theorized by Philips in 1948, and experienced some years later..
@Veritasium - YES , the earth does flip , causing cataclysms every 24000 (?) years (the last was ~12000 years ago after the Pyramids of Gizeh were build) , ancient pre-flood structiores show a totally different location of the old equator & antarctica was one warm
That was the best entertainment (New learning) I've had in years.
@FitzyyLives 年 前
ive known about this effect since i was a kid. I didn't know what it was called, but I would do this with my tv remote. it fascinated me how it was doing a half twist in the air. i started tossing the remote higher so it would spend more time in the air to get the full twist or even 1.5
Even as an experienced mechanical engineer, I am amazed at what I don't know. Thanks for this,
@shawn576 2 年 前
I always assumed this happened because I was adding spin without realizing it. The theory of a rotating object trying to minimize its kinetic energy actually makes a lot of sense.
I mean, you are adding spin without realizing it. In the point mass simulation even the intermediate axis is stable until there was a tiny deviation from exactly straight spinning. Whether it’s you unknowingly rotating it along an axis slightly different than the true intermediate axis, or air later misaligning it, it’s almost impossible to not see this effect in practice
@@lukeernst2101 if air is causing this misalignment why do we still see this effect in space ?
@singh2702 年 前
@@ayooshiyer8621 If the intermediate axis is pulled into a spin by the larger axis then this intermediate spin can only end once the larger axis has spun itself 180 degrees. By this deduction alone the outer intermediate masses must be switched hence the flip.
@@ayooshiyer8621 cause there is air on that cabin, remember that they are still breathing... i think if they left it in space without air we cant see this phenomenon.
@@hellencitaUwU the air has nothing to do with it. as derek (veritasium) said, in the reference frame of the initial rotation of the disk, the centrifugal force inherent to the rotation is what causes the disk to flip, with a frequency dependent on how much deviation the smaller masses are initially given from the axis of rotation. that's why the wingnut spins for so long between each flip, while most other things flip much sooner: the wingnut was given very nearly axis aligned rotation when it was spun off of its screw, so the centrifugal turning forces are very small for a rather long time.
I was not aware of this though I have the same ring on my little finger as you have. Regarding the “centrifugal force indicated by arrows” may miss lead some. I always refer to tangent directional arrows as the “ manifestation” of the centrifugal force, as we all know that there are no centrifugal force, only the force which is retaining object in a circular path. I love your shows, very educational though I loose you in math pretty soon. I am very old but this is no excuse. Keep it up, something among the few it worse while to watch.
@xbosta360 年 前
Impressive work at every video. Amazing! I loved the song at the start of the video 0:21 . What's the name of it?
@limelime1140 12 日 前
It took 3 different identifying apps to find it lol
@arslanmoghal5472 9 ヶ月 前
Good explanation 👍
I think i commented about this one a long while ago, i first noticed the phenomenon while flipping a TV remote just like the tennis racket. Great to get some closure :)
I have been wondering why this is for years. Thank you
7:45 - "Normally I don't like talking about centrifugal forces." Honestly, neither do I.
@frostyjhammer 4 年 前
Always heard that word pronounced "cenTRIFugal" but he's got it "centriFUgal" =`8^o
It's just too rich a subject...
Is there need in this case either? Can't it be explained by inertia as always? Mass tend to continue on it's path and that is why it ends up on wider circular route.
@@karirytkonen5811 I would have to concur...
.....they're the WORST!
Awesome video, really instructive. However, I think there’s a small mistake when it shows the images of the earth twisting (at time 10:09 - 10:18). I have a problem that I’d like to bring to your attention: the absolute direction of the earth rotation changes, whereas it should remain the same (to conserve angular momentum), only the poles should be inverted. What I mean is that, should such an event happen to the earth, we should see the sun rising in the west, whereas the images of the earth after the twist show the sun still rising in the east.
@rrs_13 年 前
@@BlurpeVODs Sun has always rose from the East, ever since the quran was written. Did you mean "sun rising from the west"?
@@BlurpeVODs 🤦‍♂️
@Samwka_ 年 前
@@BlurpeVODs Here comes the religious nut
@fridaykitty 年 前
To be fair, it would be much easier to have a simple 180 degree rotation of an image of the earth, rather than a rotation of a fully lit model of the earth with realtime sunlight. Easier for video production, but not as accurate to reality. Still would be cool to see a fully rendered simulation though
@thetrainguy 年 前
Totally fascinating. I believe the Oumuamua was also flipping over longitudinally.
@danacraig2535 8 ヶ月 前
How about ice ages? As mass is shifted from equatorial to polar ( max moment to min) I can see instability increase if the mass that has moved piles up on a preferred pole creating a miss match. This would of course have to happen fast enough so the mantle can't deform under the weight and compensate. Is this possible?
@sheslop888 年 前
Whoa! That's trippy! My brain has so many hurdles to get over before it can understand this. Like, in the tennis racket example, isn't the moment of inertia the same for the 2nd and the 3rd axis?
@hash8444 年 前
Great Channel dude
@Economivision 4 年 前
I've never been so educated, filled with a learned horror and then so suddenly and gratefully relieved in a single video. You deserve an award for creating the most educational drama in human history.
Well, at least we now know that the Earth has 3 potential axis spin directions........... you know, because it's flat....... Darn, why couldn't God have made the Earth round!!?? Lol 😂
@andyclark4627 4 年 前
Wont it have infinite axe's of rotation due to it being a ball??? (Not taking the piss or being sarcastic or trying to sound clever)
@SmashToBits 4 年 前
@@andyclark4627 it is sphere-ish. But it is heavier in areas like the gravity image of Mars he showed
@decidiousrex 4 年 前
Watch his other videos. He has some seriously cool plot twists involving nothing but science
Isn't this just a special case of the butterfly effect?
@pg5638 年 前
How about when all the ice on earth melts from its axis, is it possible then for change in spin? Will we spin faster or slower?
Like enthalpy, the rotating inertia is maximized, so would it occur in a theoretic environment where there is no loss of energy (no bump)?
@Darkdlul 年 前
So if you spin perfectly the tennis racket, will it flip ? I mean, as I understood that circle explanation, flip is due to a little deviation from the plan. Does this mean that if there is no deviation (perfectly axed spin) there is no flip ?
Wow, I've always noticed this and while I wasn't confused with how it happens or why or anything, it just confused me whenever I tossed something in the air and caught it the other way.
@deekay5343 8 ヶ月 前
Omg when I was a kid I tried flipping my phone how you described it & it always bothered me why it spun like that. Didnt ask for it but I am satisfied that I know why it does that now.
@RIP857 2 年 前
This experiment is represented in a humorous way in Kerbal Space Program. When in mid air or a vacuum, while EVA, you can perform an experiment where the Kerbal tries to spin a wingnut, but he spins instead. It's not exactly the same thing, but it's really cool to finally learn from where they drew the inspiration for that animation.
Another KSP fan.
@dimanyak373 2 年 前
"The strangest thing is not that it happens, but that spacecraft works without this part"
@ChrisMcNeely 2 年 前
lol that's awesome
@maxcorrice9499 2 年 前
Did that change? When I played it did this, maybe it’s based on specialty
I didn't have the words for it but that explanation kinda took place in my head when I saw this the first time
Great Video btw :)
@AbelCavasi 年 前
Excellent and well documented your videos! But, I have a small objection, however, regarding this video: it does not explain the sudden JUMPS that make the transition from a stable to an unstable movement.
@udhaya_shankar_V 9 ヶ月 前
Does disappearance of artic ice region cause shift in rotation axis angle? Because max MOI would change with redistribution of mass. With Antartica having heavier mass than artic
@danielingram788 5 ヶ月 前
Question. When the wing nut is spinning and changing rotation, I’m wondering if a body of water surrounding it would affect the spinning , how would it affect it?
@user-ri6ou1rx3f 8 ヶ月 前
W.G. Harter and C.W. Patterson provided what to me is an intuitive explanation of the intermediate axis theorem in a paper published in the Journal of Chemical Physics, Vo,. 80, pgs 4241-61 in 1984. Ths phenomena is a key part of the rotational spectroscopy of asymmetric top molecules and is commonly taught in Molecular Spectroscopy courses.
I’m just happy there is a scientific explanation for that
Sve je to ok ali sta je sa derbijem? 😜
@yatogami7393 4 年 前
@@Protonneutronelectron Croatian?
@yatogami7393 4 年 前
@@Protonneutronelectron kako to misliš reći?
Even if there wasn’t, there would still be an explanation, it would just be a unknown explanation.
@ftnppg1272 4 年 前
Trump supporters be like, it changes direction because god told it to. Case closed, no more discussion, solved.
Fascinating ... The pairs of three!
This is an interesting phenomenon! I wonder if the magnetic reversal that occurs once every few tens of thousands of years on our planet is similar to this phenomenon.
@markhenderson7930 11 ヶ月 前
I watched this video (or at least part of it) about 6 months ago. This morning I started jotting down some ideas I had related to this concept. I started watching this video again while writing so I could get the terminology correct. I'm going to copy and paste what I wrote here and would love any feedback: Intermediate Axis Theory to explain the Earth’s reversing magnetic field. The following are my thoughts, inspired by the JPvid video on the channel Veritasium entitled The Vizarre Behavior of Rotating Bodies. The video describes the 3 principal axes of a mass: 1st axis has the smallest moment of inertia, 3rd axis has the greatest moment of inertia, and the 2nd axis (the intermediate axis) has a moment of inertia between the first and second. Imagine the Earth’s inner solid core is spinning in what essentially is zero gravity. Because the mass of the earth somewhat equally surrounds the inner core, the gravitational forces cancel each other out. The inner core is surrounded by (suspended in) the liquid core. Suppose the inner core in not perfectly spherical and has an intermediate axis. The intermediate axis theorem, based on The Twisting Tennis Racket as published in the Journal of Dynamics and Differential Equations, Vol. 3. No. 1, 1991 and possibly the Russian discovery by Cosmonaut Vladimir Dzhanibekov while removing a wingnut in a failing space station, is summarized as follows: A body that has 3 unequal axes will spin with stability about its first and third axes, but spinning about its second, or intermediate axis, will cause it to flip 180 degrees about that intermediate axis. I don’t have the physics knowledge to explain any of this, these are just my thoughts. My Theory is that the inner core of the Earth has 3 unequal axes and is spinning about its intermediate axis. I remember some things from my days at Purdue University, many years ago, and one of those things is the involvement of the Reynolds number when scaling experiments. That is really the total of what I remember about the Reynolds number, but basically it means that I have no way to contemplate modeling this. I am re-watching the above-referenced video and I either didn’t watch it long enough the first time (about months ago) or blocked out a part of the video, but the part that just played is explaining what I just started trying to explain. I just finished the video, and there is a difference between what I started to write and what was just explained. The video concluded that the Earth as a whole must be spinning about it’s 3rd axis, but didn’t consider the solid inner core within the liquid outer core.
@pancake_ghosty 11 ヶ月 前
The last part you wrote are my thoughts too. However surely it would be possible for people to conduct an experiment with a sphere like ball with liquid inside, like a mini earth? Also the video didn't talk about the moons effect on tidal forces. Maybe the moon is what adds to the greater moment of enertia as we spin around our axis meaning it keeps us stable?