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The Bizarre Behavior of Rotating Bodies, Explained

  • The Bizarre Behavior of Rotating Bodies, Explained


    Spinning objects have strange instabilities known as The Dzhanibekov Effect or Tennis Racket Theorem - this video offers an intuitive explanation.
    Part of this video was sponsored by LastPass, click here to find out more:

    Prof. Terry Tao's Math Overflow Explanation:

    The Twisting Tennis Racket
    Ashbaugh, M.S., Chicone, C.C. & Cushman, R.H. J Dyn Diff Equat (1991) 3: 67.

    Janibekov’s effect and the laws of mechanics
    Petrov, A.G. & Volodin, S.E. Dokl. Phys. (2013) 58: 349.

    Tumbling Asteroids
    Prave et al.

    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

    Animations by Iván 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 YouTube 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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  • Anti-Gravity Wheel?


    Explanation of gyro precession:
    Less Than:
    Equal To:

    Huge thanks to A/Prof Emeritus Rod Cross, Helen Georgiou for filming, Alex Yeung, and Chris Stewart, the University of Sydney Mechanical Engineering shop, Duncan and co. Ralph and the School of Physics.

    In this video I attempt to lift a 19kg (42 lbs) wheel over my head one-handed while it's spinning at a few thousand RPM. This replicates an earlier experiment by Professor Eric Laithwaite. He claimed the wheel was 'light as a feather' and could not be explained by Newton's Laws. I wanted to find out for myself what I really felt like.

    Music By Kevin MacLeod Tempting Secrets

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  • Spinning Black Holes


    A pulsing black hole in the centre of a distant galaxy sheds light on black hole and galaxy formation. How fast are black holes rotating and how does that rotation change over its life-span?

    Huge thanks to Prof. Geraint Lewis and study author Dr. Dheeraj Pasham.

    A loud quasi-periodic oscillation after a star is disrupted
    by a massive black hole

    Special thanks to Patreon supporters:
    Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd

    Music from Colorful animation 4 serene story 2 To the stars 01 Black Vortex

    Animations by Alan Chamberlain and courtesy of NASA

  • Your Artificial Gravity Sucks!


    Today we're talking Artificial Gravity! This video has been a long time coming, and not just because it took 47 hours to edit, I took my first pass at this script about a year ago but wasn't sold on the final product. A very busy year later I've finally decided to cut the video down to a (slightly) more simple discussion about rotational stability in the context of artificial gravity. Nevertheless, this ended up being my longest science video ever, and definitely one of the most taxing for my ten-year-old computer.

    I think these are some of the best visuals I've done even though they are still fairly simple, but there is still so much to talk about. I did a lot of research for that first draft, including how you can perform maneuvers while spinning, and even a way to jumpstart the rotation using gravity gradient stabilization.


    Starship SN10 Footage is used with the permission of Cosmic Perspective:
    Thank you Ryan!

    Intro Music: Tornado by Wintergatan
    This track can be downloaded for free at
    Free License to use this track in your video can be downloaded at
    Thank you Martin!

    Main Music: Lone Wolf by Dan Lebowitz
    Available in the YouTube Audio Library

    Outro Music: Blast from

    (0:00) - Intro
    (1:31) - What is Artificial Gravity?
    (2:41) - Small Radius AG
    (4:44) - Large Radius AG
    (5:26) - Single Starship AG
    (6:39) - The Rotational Stability Problem!
    (8:51) - Multiple Starship AG
    (12:05) - What if the Tether Breaks!?
    (14:55) - What's the Best Option?
    (15:43) - Outro

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  • The Illusion Only Some People Can See


    Ames window illusion illustrates how we don't directly perceive external reality. Special Holiday deal! Go to and use code VERITASIUM to get 68% off a 2 year plan plus 4 additional months free. It’s risk free with Nord’s 30 day money-back guarantee!

    Special thanks to:
    Prof. Phil Kellman from UCLA Psychology
    Museum of Illusions in Los Angeles for the use of their Ames Room
    Curiosity Show - Video on Ames Illusion:

    Ames, A., Jr. (1951). Visual perception and the rotating trapezoidal window. Psychological Monographs: General and Applied, 65(7), i–32.

    Marcel de Heer & Thomas V. Papathomas (2017) The Ames Window Illusion and Its Variations

    Oross, Stephen, Francis, Ellie, Mauk, Deborah & Fox, Robert. (1987). The Ames Window Illusion: Perception of Illusory Motion by Human Infants. Journal of Experimental Psychology: Human Perception & Performance, 13(4), 609-613.

    Behrens, R. (1987). The Life and Unusual Ideas of Adelbert Ames, Jr. Leonardo, 20(3), 273-279. doi:10.2307/1578173

    Burnham, C., & Ono, H. (1969). Variables Altering Perception of the Rotating Trapezoidal Illusion. The American Journal of Psychology, 82(1), 86-95. doi:10.2307/1420609

    Allport, G. W., & Pettigrew, T. F. (1957). Cultural influence on the perception of movement: The trapezoidal illusion among Zulus. The Journal of Abnormal and Social Psychology, 55(1), 104–113.

    Zenhausern R. Effect of Perspective on Two Trapezoid Illusions. Perceptual and Motor Skills. 1969;28(3):1003-1009. doi:10.2466/pms.1969.28.3.1003

    Gehringer, W. L., & Engel, E. (1986). Effect of ecological viewing conditions on the Ames' distorted room illusion. Journal of Experimental Psychology: Human Perception and Performance, 12(2), 181–185.

    Long, G.M., Toppino, T.C. Adaptation effects and reversible figures: A comment on Horlitz and O’Leary. Perception & Psychophysics 56, 605–610 (1994).

    Gregory RL. Looking through the Ames window. Perception. 2009;38(12):1739-40. doi: 10.1068/p3812ed. PMID: 20192124.

    Jahoda, G. (1966). Geometric illusions and environment: A study in Ghana. British Journal of Psychology, 57(1-2), 193–199.

    V. Mary Stewart (1974) A Cross-Cultural Test of the “Carpentered World” Hypothesis Using The Ames Distorted Room Illusion, International Journal of Psychology, 9:2, 79-89, DOI: 10.1080/00207597408247094

    Margaret Kathleen Cappone (1966) The Effect of Verbal Suggestion on the Reversal Rate of the Ames Trapezoid Illusion, The Journal of Psychology, 62:2, 211-219, DOI: 10.1080/00223980.1966.10543786

    Researched and written by Petr Lebedev and Derek Muller
    Filmed by Derek Muller and Raquel Nuno
    Animations, VFX, and Music by Jonny Hyman
    Ames Room VFX and additional Ames Window animation by Nicolas Pratt
    Additional Music from Life in Color Singularity
    Large Ames window construction by GW Construction
    Video supplied by Getty Images

  • Gyroscopic Precession


    NOTE: This video will appear in a playlist on Smarter Every Day hence the references to Veritasium. Destin does lots of cool science stuff - check out his channel if you haven't already

    We have been collaborating on rotational motion, which is timely for some of the videos I've been doing lately. In this video I talk about gyroscopic precession - the wobbling of a spinning top around its axis.

    This is caused by the torque due to the object's weight. The big idea is that the torque vector increases angular momentum in the direction of torque. So if there is no angular momentum initially, it will cause the system to swing in such a direction that it is rotating with new angular momentum in the direction of the torque. However, if there was angular momentum to begin with, the torque will change the direction of that angular momentum by causing precession.

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  • The Insane Biology of: The Octopus


    Get 1 year of both Nebula and CuriosityStream for just 14.79 here: using the code realscience

    New streaming platform:


    Writer/Narrator/Editor: Stephanie Sammann
    Editor: Dylan Hennessy (
    Illustrator/Animator: Kirtan Patel (
    Animator: Mike Ridolfi (
    Sound: Graham Haerther (
    Thumbnail: Simon Buckmaster (
    Producer: Brian McManus (

    Imagery courtesy of Getty Images


  • An Introduction to Ellipsoids!


    This is from the middle of my much-longer video Ellipsoids and The Bizarre Behaviour of Rotating Bodies.

    Huge thanks to Ben Sparks who made the ellipsoid animations. Check out their GeoGebra files:

    Subscribe to my main Stand-up Maths channel over here:

  • Can Humans Sense Magnetic Fields?


    Research has found some human brains can pick up on rotations of geomagnetic-strength fields as evidenced by drops in alpha wave power following stimulus. For more, see

    Huge thanks to:
    Prof. Shinsuke Shimojo, Connie Wang, and Isaac Hilburn, plus Prof. Joe Kirschvink. Their lab:

    Special thanks to Patreon supporters:
    Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd

    Additional filming by Whitney Clavin

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  • Chaos: The Science of the Butterfly Effect


    Chaos theory means deterministic systems can be unpredictable. Thanks to LastPass for sponsoring this video. Click here to start using LastPass:
    Animations by Prof. Robert Ghrist:

    Want to know more about chaos theory and non-linear dynamical systems? Check out:

    Butterfly footage courtesy of Phil Torres and The Jungle Diaries:
    Solar system, 3-body and printout animations by Jonny Hyman
    Some animations made with Universe Sandbox:
    Special thanks to Prof. Mason Porter at UCLA who I interviewed for this video.

    I have long wanted to make a video about chaos, ever since reading James Gleick's fantastic book, Chaos. I hope this video gives an idea of phase space - a picture of dynamical systems in which each point completely represents the state of the system. For a pendulum, phase space is only 2-dimensional and you can get orbits (in the case of an undamped pendulum) or an inward spiral (in the case of a pendulum with friction). For the Lorenz equations we need three dimensions to show the phase space. The attractor you find for these equations is said to be strange and chaotic because there is no loop, only infinite curves that never intersect. This explains why the motion is so unpredictable - two different initial conditions that are very close together can end up arbitrarily far apart.

    Music from The Longest Rest A Sound Foundation Seaweed

  • Ellipsoids and The Bizarre Behaviour of Rotating Bodies


    Derek's video: The Bizarre Behavior of Rotating Bodies, Explained

    Based on this amazing footage: Dancing T-handle in zero-g

    Terence Tao's original answer, with update.

    Support me on Patreon and I can make more video like this!

    We are sat so close because we filmed this in the “before times” of late 2019.

    Huge thanks to Helen Czerski for spinning a book in zero-G for us.

    Cosmic Shambles (who convinced ESA to launch Helen) also have a Patreon:

    Ben Sparks made the ellipsoid animations for me. Check out their GeoGebra files here:

    Rotating 3D book was thanks to Tim Waskett of Stone Baked Games.

    There are plenty more Matt and Hugh videos to learn about moments of inertia and suchlike.

    Hugh Hunt is the Cambridge University Reader in Engineering Dynamics and Vibration. I know!

    Zero G footage courtesy The Cosmic Shambles Network working in association with the European Space Agency. In flight footage shot by Melanie Cowan. External plane footage courtesy Novespace.

    - At 11:00 and 14:23 I say the axes correspond to the axes of rotation but technically they represent the three different directions of spin. Which is why they are labelled with omegas representing the angular velocities in those directions.
    - At 05:52 the ellipsoid equation should be “volume” not “area”. First pointed out by Ihsan Khairir. My fault for not paying attention editing the text after copying the previous equations.
    - Oh my goodness. At 11:50 we missed an “L” in ellipsoid. First pointed out by Daniel Burger. I’m so embarrassed.
    - Let me know if you spot any other mistakes. Or, you know, make a whole video about it.

    As always: thanks to Jane Street who support my channel. They're amazing.

    Filming and editing by Trunkman Productions
    Additional filming by Melanie Cowan
    Audio by Peter Doggart
    Music by Howard Carter
    Design by Simon Wright and Adam Robinson

    MATT PARKER: Stand-up Mathematician
    US book:
    UK book:
    Nerdy maths toys:

  • Rigid Body Motion and the Dzhanibekov Effect


    I give an intuitive explanation of the Dzhanibekov effect on a rotating rigid body, and discuss its relationship with the intermediate axis theorem.

    Simulations were created using glowscript (, developed by David Scherer and Bruce Sherwood.

    The simulations are based on the Lagrangian equations of motion for a simple rigid body. I will present the mathematical details in an accompanying video.

    Thanks to Derek Muller (Veritasium) and Matt Parker (Stand-up Maths) for permission to use clips from their videos.

  • Intermediate Axis Theorem - Explained


    A demonstration of the Intermediate Axis Theorem (also known as the Tennis Racket Theorem or the Dzhanibekov effect). Visuals provided by Kerbal Space Program.

    Physics vs KSP:

    Stopping Spinning Rockets:

    Orbital Mechanics:

    Drafting Rockets:

    Dance, Don't Delay by Twin Musicom is licensed under a Creative Commons Attribution license (

  • Rotating Solid Bodies in Microgravity


    Saturday Morning Science

  • BIZARRE spinning toys


    Spinning toys and tops have unusual behaviors. The famous tippe top flips itself over and spins on its stem. The PhiTOP stands up on its end, which you can also do with a hard-boiled egg. These behaviors all have to do with torque and angular momentum, like a bicycle wheel precessing around a rope due to gyroscopic behavior.

    Defining Gravity with Tim Blais:

    A Cappella Science:

    Crash Course Physics:

    Help us translate our videos!

    Creator: Dianna Cowern
    Writer: Sophia Chen
    Editor: Jabril Ashe
    Animator: Kyle Norby


    More resources:

    Music: APM

  • The bizarre behavior of a rotating body was NOT explained - rare


  • Dancing T-handle in zero-g, HD


    HD video of the installation handle on Space-DRUMS in free floating rotation showing a bi-stable state due to intermediate moments of inertia.

  • Dzhanibekov effect demonstration in microgravity, NASA.


    Principal axes of a tennis racket.
    The tennis racket theorem or intermediate axis theorem is a result in classical mechanics describing the movement of a rigid body with three distinct principal moments of inertia. It is also dubbed the Dzhanibekov effect, after Russian cosmonaut Vladimir Dzhanibekov who rediscovered one of the theorem's consequences while in space in 1985

  • The Tennis Racket Theorem Or Intermediate Axis Theorem - Dzhanibekov Effect


    The tennis racket theorem: will Earth suddenly flip its axis?
    Usually, scientific topics have very strange names that might not be so funny or attractive, but this isn’t the case of the Tennis Racket Theorem, also known as the intermediate axis theorem.
    This subject is strictly linked to a very weird event a Russian Cosmonaut called Vladimir Dzanibekhov observed while in space in 1985. By removing a screw in the orbiting station during an experiment, he made it turn around an axis, but suddenly the bolt started to change the direction of rotation by itself, without any external help. He was really surprised, and the event took its name after the scientist: the Dzanibekhov Effect.
    But what is the link with the Tennis racket Theorem? Have you ever tried to flip a phone or a racket? Isn’t there something really strange and inexplicable? Have you noticed it? Well, if not, this video will introduce you to the bizarre behavior of rotating objects. Did you know that the flipping of a little bolt was able to scare scientists to deat-, suggesting a possible ending of human life on Earth? Do you want to know more about that? Stick with me and I’ll tell you everything in a moment.

    Some puzzling questions have been already made, but in order to give an appropriate answer to all of them it’s surely better to start from something that has been discovered many years ago.
    Classical physics, primarily created by Newton in the sixteenth century, was the most important field of research in science until the late 19th century. In this length of time the majority of scientists studied planets, that are used to have a circular movement around their star. Moreover, they also happen to rotate around their axis, and this is the reason why the Sun seems to move in the sky and why our days are only partially illuminated by solar light. In order to study these phenomena, physicist elaborated an entire theory (according to Newton’s principles) about moving particles and objects: Classical Mechanics.
    Nevertheless, this funny and silly theorem brought uncertainty in the scientific community. Major concern arose as the hypothesis of a similar behavior could be assumed by the Earth. Some physicists were scared by the idea of our planet flipping its axis of 180 degrees. The outcome of such a catastrophic event would be terrible. Imagine living in a world in which the Antarctic suddenly takes the place of the south pole and viceversa?
    Are you afraid by this possibility? If yes, don’t go nuts. I’ll rapidly comfort you by explaining that such a consequence is impossible.
    More and more experiments were taken on the international space station with other types of objects. They tried to make a liquid bottle flip over its different axis and a strange event happened. The body started to rotate around the axis with the largest moment of inertia, which is the one with the minimum kinetic energy.
    Why does this happen? When a fluid is inside the body, energy isn’t conserved due to friction and heat dissipation. As a result of that the object loses energy and “tends” to the rotation axis which requires less energy to spin.
    A similar event might happen if the body doesn’t contain liquid but has a shape that favors friction.
    Returning to our major concern: will earth flip its axis of rotation suddenly causing the possible destruction of cities and landscapes? Obviously not. And why? Because earth is not properly a rigid body as the tennis racket or Dzhanibekov’s screw. As a matter of fact, Earth is composed also by a lot of fluids both externally and internally.
    Consequently, in the course of its history it has gradually lost energy and has started to rotate around the axis with the minimum kinetic energy and the maximum moment of inertia, which is the axis that passes through north and south pole.
    In conclusion, the astonishing Dzhanibekov effect discovered by the Russian cosmonaut in 1985 is just a small derivation of classical mechanics, particularly of Euler’s equations about rotating rigid bodies. Although this theorem has some funny application as the one we have seen with the tennis racket, its conclusions are very deep and have temporarily made a full community of trained physicists doubt about the behavior of their own planet. Whenever you’ll go have an easy tennis match with your friends, those rackets will have a totally different meaning for you!
    This video ends here! Thanks for watching everyone! Did you find this topic exciting? Are you amazed by the consequences that a small and simple theorem can have on our entire planet? Are you afraid by the hypothesis of a flipping earth with a consequent destruction of humanity? Is there anything more you want to hear about the Dzanibekhov effect, the classical mechanics or the rotation of rigid bodies?

  • Dzhanibekov effect


    Study of the stability of a solid body isolated in the space
    and rotating without external torque.

    See also the video

    The Bizarre Behavior of Rotating Bodies, Explained

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  • International Toys in Space: Spinning Top


    Astronaut Peggy Whitson investigates how a traditional spinning top performs in a microgravity environment. Whitson narrates the video.

  • The reason that spinning tops rise, explained logically


    Here I explain in poor words and without algebra the reason that spinning tops tend to rise in vertical position while spinning, if the spin speed is high enough.

    Light Awash di Kevin MacLeod è un brano autorizzato da Creative Commons Attribution (

  • Does Water Swirl the Other Way in the Southern Hemisphere?


    The definitive answer about the direction water swirls in two hemispheres
    Sync the videos yourself:

    For the record Destin and I repeated the experiment 3-4 times each in each hemisphere and got the same results every time.

    The idea that water going down a drain or flushed down a toilet swirls in opposite directions in the Northern and Southern Hemispheres has a long history. But few have ever done the experiment. Destin from Smarter Every Day and I performed identical experiments in the Northern and Southern hemispheres. What we found is the direction of water swirl in a toilet, sink, or bathtub is determined by other sources of angular momentum. However if the body of water is big enough, e.g. a kiddy pool, and left still for long enough (at least 24 hours), then the Coriolis effect is observable with water swirling counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere.

    Veritasium on Instagram:
    Patreon Support Link:

    Smarter Every Day Instagram:
    Patreon Support Link:

    Gordon McGladdery did all of the sound design for the video. We used two songs from other artists (licensed of course). Derek split the first one up so it fades from video to video, and Gordon split the instruments up on the second one. There are violins on one video and percussion on the other for example. It's really neat.

    The neat earth animation at the beginning and the synchronizing timer was made by He also made still images of the earth from the top and the bottom.

    Thanks to Vanessa for filming in Sydney:


    There was a study performed at MIT years ago ( that explained the physics involved. We repeated some of these demonstrations, but on opposite sides of the globe…and in a way that can be easily understood.
    This site is a great resource on the Coriolis effect and ways people have gotten it wrong:

  • Spinning Disk Trick Solution


    ZoggFromBetelgeuse's solution:
    This is a preliminary solution to the spinning disk trick based on the commonly cited tippe top explanation. I have my doubts that it tells the whole story because the disk seems to tilt, so the argument about constant angular velocity is in doubt. I wonder if the weight of the disk plays a more important role in making it flip. Plus, I think the disk appears to roll without slipping while the lighter side is moving down. This violates one of the assumptions of the tippe top explanation. So why am I publishing this now? I feel bad it has been two weeks and I haven't posted the answer yet so let's consider this a starting point for a work in progress...

  • Bullet Block Explained!


    Watch the bullet block experiment first:
    Click for a free audiobook from Audible:
    An interactive vignette of the bullet block

    Can you figure out the spinning disk?

    Thank you all for the awesome video responses and comments!!

    Web comic:
    Wired Blog:
    Science Blogs:
    Scientific American:
    Le's Blog:

    Video responses from which I borrowed:

    Thanks to everyone at RIT and Dickinson College who helped with the making of this video:
    Rochester Institute of Technology
    Robert Teese, Katelyn Wilkerson, Andrew Gillie, Andrew Stidwill

    Dickinson College
    This experiment was the brainchild of David Jackson based on a demo at Princeton.
    Priscilla Laws, Catrina Hamilton-Drager, Maxine Willis

    High-speed camera support:
    Charles Zwemer and Bria Antoine

    Music: Temper Trap Love Lost (Instrumental) and Lights & Motion Epilogue licensed from

  • Weird Physics Phenomenon Of Rotating Bodies In Space || Turning Effect Of Rotating Bodies #Shorts


    Weird Physics Phenomenon Of Rotating Bodies In Space || Turning Effect Of Rotating Bodies
    - This video clip is of a Russian cosmonaut who found a weird phenomen about rotating bodies. He opened a screw which continued to rotate in space. But the weird part was that it would change its direction after rotating in a particular direction

  • Free rigid body, stability about the three principal axes, qualitative analysis of spinning objects


    Dr. Shane Ross, Virginia Tech. Lecture 14 of a course on analytical dynamics (Newton-Euler, Lagrangian dynamics, and 3D rigid body dynamics). The tennis racket theorem; instability of rotation about the intermediate principal axis (jump to 42:44)

    Online course playlist

    0:00 A demonstration of yaw-pitch-roll from the built-in gyroscope of an iPad

    Then a few main topics

    7:24 Free rigid body. First, the stability of the motion for a torque-free rigid body, that is a rigid body which can be approximated as having no external moments on it. We try to give an intuitive explanation as to why pure rotation about any axis is not possible. Instead, there are only three directions about which pure rotation is possible, corresponding to the principal axes. The principal axes can be ordered by the corresponding value of the moment of inertia for rotation about that axis. In general, we have I_max, I_int, I_min, corresponding to the maximum, intermediate, and minimum moment of inertia. We discuss the stability of rotations about these axes: rotation about the maximum and minimum principal axes are stable, whereas ...

    42:44 rotation about the intermediate axis is unstable

    51:33 Why can't we always get pure (steady) rotation about an axis for a free rigid body?

    1:03:20 Qualitative analysis of spinning objects. We discuss the qualitative analysis of a spinning body, where the body is either spinning rapidly or is a system with a connected rapidly spinning rotor. The approach we mention is useful to develop a qualitative understanding of the expected behavior. We apply the analysis to a gyroscope with a rapidly spinning flywheel, which is suspended from a string.

    You can also see the entire class lecture notes in PDF form here

    and in OneNote form here:

    Lecture 2020-10-08, Fall 2020

    Author's website:

    Dzhanibekov effect Tennis racket theorem intermediate axis theorem instability about the intermediate middle medium axis

    #RigidBody #FreeRigidBody #gyroscope #Dzhanibekov #instability #IntermediateAxis #TennisRacketTheorem #QualitativeAnalysis #PrincipalAxis #TorqueFree

  • Spinning Tube Trick Explained


    When a tube spins with an X and an O labelled at either end, why do we see only one letter during the rotation?

  • Dzhanibekov Effect applied to Earth Gravitational Model


    My latest Moon video.

    The earth is an object in space, it's not flat, and it's also not a perfect sphere, especially in terms of gravity. But it is subject to the laws of physics, and since there is much debate about the earths geometric shape, global warming and why the weather is getting increasingly more extreme, without taking any sides, I provide an explanation that the earth is subject to the laws that can be seen in all spinning objects in space and explained using the Dzhanibekov effect, also known as the tennis racquet effect.

    One important note in this simulation, is that the EGM96 is a snapshot in time. The distribution of the earths gravity changes constantly with tectonic movement, subterranean flows, freezing/thawing of the poles throughout the seasons. So until I can process data of earths gravity distribution over certain time frames, this simulation is really only applicable if the earth became a solid body who's gravity distribution remained constant from the time the EGM96 was created.

    The video I used at the start of this video is public domain, and can be viewed from the Wikipedia link,

    Model at

    The 3D model in this video was created by me and can be downloaded from here

    If you use the model and/or parts of this video, then please credit me with the link to the repository and/or this video. Thanks for your interest.

    Interesting Reads:

  • Rotating bodies in microgravity and cat flip!!!


    Spinning objects have strange instabilities known as the Dzhanibekov effect or tennis racket Theorem. Also i show video rotating rigid and solid bodies in space. At last you can see how cat flip on earth!

  • Spinning T-Handle in Space in MOMDYN


    Replicating the unstable dynamics of a spinning part in zero gravity using MOMDYN version 0.9.4. If you’re interested in joining the beta test, check out

    A sample of the original video and a good explanation for why this happens is at I do my own treatment of the maths bit at

  • Most BIZARRE Sea Creature Behavior!


    Check out the most bizarre sea creature behaviour! This top 10 list of weird and strange deep sea animals have some odd behavior you'll be surprised to hear!

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    11. Be The Leaf
    So, when you're in the waters of the oceans or seas below, you know that to survive, you have to adapt to what's around you. Whether that be through knowing what predators are a threat to you, or knowing your surroundings, it's better to be prepared than eaten. However, the Orbicular Batfish takes it to a whole other level.

    10. No Head On its Shoulders
    Sometimes a behavior doesn't mean a personality trait, it can simply mean that there's something about the creature that just makes it weird. It can’t help it! A great example of this is the Ghoulfish.

    9. The More To Smell You With
    There are cases when an adaptation or skill is useful beyond the ways that people perceive them. Animals surprise humans all the time with what they can do with what they have. But, in certain cases, it's just flat out strange what's going on. Like what? Well, how about how Bony Fish actually have more than one set of nostrils??

    8. This Is My Spot
    One of the coolest things to see on certain nature documentaries about the ocean are the bizarre movements of octopuses and other sea creatures. From schools of fish moving around to sharks launching themselves out of the water to catch food, it’s highly entertaining.

    7. See Me Now?
    Light is meant to be everywhere, even in the darkest of places. And many creatures under the water use light to move around, or to lure in creatures for them to eat. However, there are cases where using light actually seems like a detriment for creatures instead of a helping asset.

    6. Will You Stand?
    When you think about fish, what are the characteristics you think of? Do you picture it swimming around? With its fins, its gills? And at any moment have you ever wondered, Man, wouldn't it be cool if a fish could stand? No, you don't, do you. But, that's exactly what the Tripod Fish does!! It uses extensions on its fins to actually stand underwater.

    5. Water Assassins
    While this list is about odd behavior, some of these ones are just plain scary in how natural this behavior is for them. For example the Archerfish. A fish that truly earned its name for the scariest (and admittedly coolest) of reasons.

    4. A Whale Of A Congregation
    Animals are unique in many ways, and just like humans, they can either be very social, or very solitary. It just depends on the species and their natural instincts. So, when a solitary creature suddenly starts popping up with dozens upon dozens of its friends, people take notice. And that's exactly what's been going on with the Humpback Whale.

    3. Flip Or Fly
    All animals need to eat, right? And creatures have come up with some unique ways to get their food! From Manta Rays to Eagle Rays, these majestic creatures have all been seen leaping out of the water like crazy!! Scientists were very intrigued when they started studying their eating habits.

    2. Inside Out
    Squids are some of the most amazing, terrifying, and unique creatures in the waters. You've already met the Googly-Eyed Squid, but now, here’s a squid that can do some extremely odd things.

    1. Puke Attack
    So how would you defend yourself against an enemy? Would you use your fists, your feet, a weapon? Or, maybe you'll try and use their own strength against them? All’s fair when you’re threatened but it’s not so easy when you’re in the deep sea!!!

    Origins Explained is the place to be to find all the answers to your questions, from mysterious events and unsolved mysteries to everything there is to know about the world and its amazing animals!

  • McPherson, Hester & Massa - Just Because


    3:13 - Jane's Addiction
    10:44 - 90's Pop Megamix

    April 6, 2021 - Nature Bats Last Radio

    Could Life on Earth Have Come From Space
    Thermodynamics and the End of the Universe - Energy, Entropy, and the fundamental laws of physics
    The Plan to Revive the Mammoth Steppe to Fight Climate Change
    The Bizarre Behavior of Rotating Bodies, Explained
    Religulous - The Final Message

  • Rotating Bodies Physics


    Explanation for the phenomenon -

  • ap10.5 angular Momentum


    University physics

  • Эффект Джанибекова в земных условиях | 1 курс


    Победитель конкурса студенческих проектов 1 курса ФТФ ИТМО Изучение эффекта Джанибекова

    Воропаев Илья,
    Гущин Даниил,
    Ивлиев Вячеслав,
    Карпунов Иван,
    Козин Роман
    Науч. рук.:
    Коробков Максим

    В ходе проекта нами были изготовлены рабочая экспериментальная установка и две модели шаров с неравномерно распределённой по объёму массой, наглядно демонстрирующие проявление эффекта Джанибекова в условиях земной гравитации. Мы численно решили систему дифференциальных уравнений Эйлера в зависимости от значений моментов инерции и начальной угловой скорости, подтвердив тем самым неустойчивость вращения вокруг промежуточной оси. Также теоретически была получена формула для расчёта периода переворота асимметричного тела при неустойчивом вращении. Было экспериментально показано, что формула для вычисления периода верна с учётом погрешности. Была найдена аналитическая зависимость моментов инерции шара, разделённого на доли, от их угла раскрытия.

    К сожалению, нам не удалось рассмотреть вращение тел при малых угловых скоростях, так как мы не смогли настолько минимизировать силу вязкого трения. Установка хорошо работает при больших угловых частотах вращения шара, но при этом период переворота довольно мал, что снижает наглядность демонстрации.

    Впоследствии мы хотим доработать механизм раскрутки шара в подшипнике. Вместо закручивания руками мы планируем изготовить устройство, которое будет придавать не приблизительную, а точную начальную скорость вращения шара, тогда точность эксперимента повысится и можно будет делать более точные оценки по работе эффекта.

    0:00 Введение
    0:30 История
    1:28 Задачи
    2:09 План проекта, командная работа
    2:26 Варианты реализации
    2:41 Международное сотрудничество. Установка Пола Норда.
    3:13 Бюджет проекта
    3:24 Теоретическая часть. Моменты инерции.
    4:04 Уравнения Эйлера
    4:13 Закон сохранения энергии и закон сохранения момента импульса
    5:05 Зависимость времени от угловой скорости
    5:20 Эллиптические функции Якоби, эллиптический интеграл.
    5:33 Формула для периода переворота
    5:55 Модель шара с перегородками
    6:10 Формулы для расчета момента инерции шара с перегородками
    6:30 Аналитические зависимости для моментов инерции шаров, заполненных глиной, парафином
    7:07 Динамика вращения. Численное решение системы дифференциальных уравнений Эйлера
    7:53 Аналитическая зависимость периода переворота от начальной скорости вращения
    8:08 Сборка установки и изготовление шаров
    8:58 Вид экспериментальной установки
    9:13 Демонстрация эффекта
    9:29 Анализ результатов
    10:55 Итоги работы
    13:58 Демонстрация установки, вопросы

    Список литературы
    [1] Л. Д. Ландау, Е. М. Лифшиц. Теоретическая физика, Том 1 Механика. ФИЗМАТЛИТ 2001
    [2] P. M. Trivailo, H. Kojima. Discovering Method of Control of the “Dzhanibekov’s Effect” and
    Proposing its Applications for the Possible Future Space Missions. Trans. JSASS Aerospace Tech. Japan 2019
    [3] Tennis racket theorem.
    [4] В. Н. Винчаков, И. П. Ипатова. Применение тензоров и матриц в физике твердого
    тела, Учебное пособие. Ленинград 1979
    [5] А. П. Маркеев. Теоретическая механика. Издание второе, Ижевская республиканская
    типография 1999
    [6] Д. В. Сивухин. Общий курс физики, том 1, Механика. ФИЗМАТЛИТ 2016
    [7] Veritasium The Bizarre Behavior of Rotating Bodies, Explained
    [8] Решение систем обыкновенных дифференциальных уравнений в среде MATLAB.

    [9] Paul Nord. Laboratory technician. Valparaiso University, Indiana, the USA.

    Pictures credits:

    Новый физтех:

    #Новыйфизтех_проекты #ITMO #новыйфизтех

  • الشيء العجيب في تصرف الأجسام الدوارة


    الأجسام الدوارة لديها عدم اتزان غريب يدعى تأثير دزانيبيكوف أو نظرية مضرب التنس. هذا الفيديو يشرح هذه الظاهرة ونبحث عن إذا من الممكن أن يتغير اتجاه دوران الأرض. اشتركوا في قناة فريتاسيوم بالعربي
    للحصول على حلقات جديدة كل أسبوع

    شرح البروفسور تيري تاو لمعادلة تجاوز الرياضيات

    مضرب التنس الملتوي - The Twisting Tennis Racket
    أشباغ، إم إس، تشيكون، سي سي وكوشمان، أر إتش جاي دين دف إيكوات (1991) 3: 67.

    تأثير جانيبيكوف وقواعد الميكانيك - Janibekov’s effect and the laws of mechanics
    بيتروف أي جاي وفولودين، إس إي دوكل. (2013) 58:349

    الكويكبات المتدحرجة - Tumbling Asteroids

    المعادلة المحددة لمسار المجسم الحر المتصلب واستخدامه في شق الأساليب
    The Exact Computation of the Free Rigid Body Motion and Its Use in Splitting Methods

    الرسوم المتحركة من إيفان تيلو وإيساك فرايم

    شكر خاص للأشخاص اللذين ناقشوا هذا الفيديو معي:
    رائد الفضاء دون بيتيت
    هينري رايخ من دقيقة فيزياء (MinutePhysics)
    جرانت ساندرسون من 3blue1brown
    فيرت ديدر - قناة يوتيوب روسية

    في الأسفل شرح مفصل من هنري رايخ الذي برأي يفصل لماذا المحاور 1 و 3 يكونوا إجمالا ثابتين بينما المحور الثاني ليس كذلك:

    بشكل عام قد تتخيلون أن المجسم يدور في عدة اتجاهات، عناصر الطاقة والزخم قابلة للتغير حين يبقى مجموع قوة الدفع ثابتة.

    لكن في حال محور 1 الطاقة الحركية تكون في أعلى مستوى ممكنة للزخم الزاوي الموجود، وفي حال محور 3 الطاقة الحركية تكون في أدنى مستوى ممكنة للزخم الزاوي الموجود (والتي بالإمكان أن يثبت بسهولة من معادلات الحفاظ على الطاقة والزخم، ويعتبر بديهيا في واقع الأمر أن القوة الحركية متناسبة مع مربع السرعة حين الزخم متناسب مع السرعة - إذا في حال المحور 1 الأوزان الأخف يجب أن تدور بسرعة أسرع للزخم الموجود، وبالتالي سيكون لديها طاقة أعلى، والعكس صحيح للمحور 3 في مكان ما تدور كل الأوزان: الطاقة ستكون في أدناها). في واقع الأمر، هناك عدم مساواة حسابية - إذا كانت الطاقة في أعلى درجة ممكنة، ليس هناك أي مجموع قوات الزخم ممكنة غير L2=L3=0، والعكس كذلك إذا كانت الطاقة في أدنى مستوى ممكنة.

    ولهذا السبب، في حالة محور 1 تكون الطاقة عالية جدا لدرجة أنه ببساطة ليس هناك أي مجموعات أخرى لقوات الدفع الزاوي، L1، L2، و L3 - المجسم يجب عليه أن يفقد طاقة لكي يدور بشكل مختلف. وفي حالة المحور 3، الطاقة منخفضة جدا لدرجة أنه بنفس الطريقة ليس هناك أي مجال للمجسم أن يدور إلا حول محور 3 - يجب عليه أن يكسب طاقة. لكن ليس هناك قيود لمحور 2، بما أن معدل الطاقة تكون بين المعدل الأعلى والأدنى. هذا وبالإضافة إلى تأثير النابذة (طاقة الطرد المركزي) وذلك يعني أن مكونات الزخم ستتغير.

    الفيديو الأصلي باللغة الإنجليزي:

    اسم الفيديو الأصلي باللغة الإنجليزية:
    The Bizarre Behavior of Rotating Bodies, Explained

    إدارة القناة:

    ستوديو الدبلجة
    Racti Art Production
    مدير القناة: وسام الشيخ حسن

  • 12 Make things rotate


  • Torque free motion of a rigid body about intermediate inertia axis


    Torque free motion of a rigid body about intermediate inertia axis. Shows precession. Angular velocity, angular momentum, and body axes shown.

  • Intermediate Axis Unstable Spin Simulation


    A simulation of a body in torque-free motion spinning about its intermediate axis which causes a quasi periodic 180 degree flip in spin axis.

    This is the first of a few sneak peeks I will be posting before coming out with the Introduction to Spacecraft Attitude Control with Python video (and the subsequent series).

    Astronauts have done this experiment on the International Space Station showcasing this phenomenon in real life. This effect is also called the tennis racket theorem or the Dzhanibekov effect if you want to do more research on it before I cover it in a future video.

  • Tennis Racket Theorem



  • 3 axis gimbal rotation explained in a unique way DJI Pro 2 DJI Zoom


    Please, support this channel, most videos, google has restricted for monetization; please consider a recurring donation of as little as dollar a month, it will allow me to maintain this pace of sharing and helping
    Please, keep in my mind, as I make this videos, in the initial stages of data gathering I WILL make mistakes and get data WRONG as my wires ''cross and uncross'' in my brain.
    Also, read my comments in the ''community page'' , it explains what this Youtube channel and forum will accomplish.
    Very importantly, we need the workers from these troubled videos to comment and share their data so we can expose the truth and not some narrative our local and Federal government wants to release. You, the workers know the real deal! Share it, no company is paying you extra to protect them, you owe it to the people that can before and after you. OSHA will not protect you, they also only want money for the government, when is the FIRST time OSHA has given a dime to the victim workers? NOT ONE TIME... NO respect meant to the employees of OSHA, I know a few of you personally and I know how you feel about your job... But, it is a job so stick with it.
    Please, do my one favor, give me a thumbs up or down based on your thoughts of content... Your comments and thoughts are appreciated. Please, keep in mind, that I love the human mind and how it works and processes... So, I have more of a ''deep thought on subjects that may include the ''intent'' (inside my evaluations in my videos).
    Thank you for considering. 3 axis gimbal rotation explained in a unique way
    This would be what is going on in your DJI pro 2 and DJI Zoom
    The three axis gimbal and why they are so smooth in relationship to movement!

  • Dzhanibekov Effect


    This can explain Newton's 1st Law..
    A body can't change its State of motion ,Till any external force act on it

  • Centrifugal Instability


    This movie shows examples of centrifugal instability in a 20 cm diameter by 20 cm deep cylindrical tank of water situated on a DJ turntable. We spin up the tank of water so that all the water is in solid body rotation. Then we slow down the rotation rate. The fluid adjacent to the tank boundaries slows with the tank and the interior fluid maintains its original speed. The faster interior fluid then centrifuges its way outwards into the slowly fluid on the sidewall. The occurs in the form of centrifugal rolls. The rheoscopic fluid that is added to the water allows this instability to be nicely visualized.

  • Bizarre behavior - Intro to Psychology


    This video is part of an online course, Intro to Psychology. Check out the course here:

  • Objects in Microgravity #6--Gyroscope Physical Explanation


    In this video, Toby Dittrich provides an explanation of the physics operating on a gyroscope that is in free fall and therefore under near-zero gravity conditions.

    Toby Dittrich is a physics instructor at Portland Community College in Portland, Oregon and has conducted a variety of experiments in cooperation with the Dryden Drop Tower laboratory and facility. The DDT is 31.1m (102 ft.) in height and provides approximately 2.1 seconds of micro-gravity conditions inside the drop box. The experiments generally consist of objects being dropped in the DDT that are recorded by a high-speed videocamera in the drop box.

    For more information about the DDT, go to:

    For Toby Dittrich's entire Drop Tower Physics playlist, go to:

    This video produced by the Video Production Unit at Portland Community College:

    Michael Annus: Producer, director and editor
    Derek Skeen: Camera and lighting
    Jill Petracek: Grip and lighting

  • Centripetal Force vs Centrifugal Force EXPLAINED


    I hope this explains the differences between centripetal and centrifugal force clearly. Please feel free to leave your questions in the comments! :)
    Animation was done using Manim!

  • Ep.20 Rotating bodies in microgravity


    Saturday Morning Science - Dr. Don Pettit demonstrates rotating bodies in the International Space Station.

  • This Particle Breaks Time Symmetry


    Increasing entropy is NOT the only process that's asymmetric in time.
    Check out the book:
    This video was co-written by Daniel Whiteson and Jorge Cham
    You can also check out PhD Comics:

    Special thanks to Patreon supporters:
    Tony Fadell, Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Joshua Abenir

    Support Veritasium on Patreon:

    Original paper on parity violation by the weak force by Lee and Yang:

    More on B-meson oscillations and time reversal violation:
    Physics World Article:
    Original paper:

    Physics consultant: Prof. Stephen Bartlett

    Studio filming by Raquel Nuno

  • HTPIB10L Stokes Tips




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