Introduction to Tensors

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  • čas přidán 8. 06. 2018
  • My tensor series is finally here! In this video, I introduce the concept of tensors. I begin by talking about scalars, then vectors, then rank-2 tensors (whose explanation takes up the bulk of the video since these are probably the most difficult to understand out of the three).
    I then move on to define tensors (without specifying their transformation properties), after which I conclude the video with a short discussion on rank-3 tensors, which may be represented by 3-D matrices/arrays.
    Questions/requests? Let me know in the comments!
    Pre-requisites: You basically need to know what vectors, scalars, and matrices are. Nothing much more to it. A 1st-year Physics + Linear Algebra course should be enough.
    Lecture Notes: drive.google.com/open?id=1O5G...
    Patreon: www.patreon.com/user?u=4354534
    Twitter: / facultyofkhan
    Special thanks to my Patrons for supporting me at the $5 level or higher:
    - Jose Lockhart
    - Yuan Gao
    - James Mark Wilson
    - Marcin Maciejewski
    - Sabre
    - Jacob Soares
    - Yenyo Pal
    - Lisa Bouchard
    - Bernardo Marques
    #Tensors #TensorMath #TensorIntro

Komentáře • 386

  • @FacultyofKhan
    @FacultyofKhan  Před 4 lety +78

    If you all liked this video, then make sure to check out the remainder of my playlist on Tensors, because there's more where that came from!
    czcams.com/play/PLdgVBOaXkb9D6zw47gsrtE5XqLeRPh27_.html

    • @kunalvshah
      @kunalvshah Před 4 lety +1

      Hi, which sw/hw you use for digital handwriting? - awesome video by the way. My tensor concepts are clear now. I have not learned this in my collage.

    • @RAJDEEPswarnakar6071
      @RAJDEEPswarnakar6071 Před 2 lety

      Bhai mobiel nabar

    • @johnkibathi7202
      @johnkibathi7202 Před 11 měsíci

      What software do you use to make these videos, am a huge fan of your eloquent presentations

  • @KeyMan137
    @KeyMan137 Před 5 lety +287

    I have a bachelor's degree in Physics but we didn't talk about Tensors much. This was an excellent introduction!

    • @HighestRank
      @HighestRank Před 4 lety +5

      Spencer Key phisyxs would be (un)concerned with mostly Brownian motion and other nullificable components. Mechanical(civil) and engineering disciplines plus their common prerequisite transcendent mathematics would need to look more closely at ‘stress mechanics’.

    • @jameswood8999
      @jameswood8999 Před 4 lety +6

      I have a BS degree in physics too, went to graduate school to learn tensors, more clear here.

    • @sidddddddddddddd
      @sidddddddddddddd Před 4 lety +8

      That is strange. We studied tenors in the 2nd year at our university, GR in the third and introduction to quantum gravity in the 4th. It has been a crazy ride.

    • @emvee5719
      @emvee5719 Před 4 lety

      BSME and we didn't cover tensors either. It's important.

    • @lachyt5247
      @lachyt5247 Před 3 lety

      I don't understand how that's even possible did you not take E&M? Tensors were a huge aspect of Jackson.

  • @CazoDK
    @CazoDK Před 5 lety +395

    This is the best video about tensors on youtube. The only video that covers the actual definition of a tensor: a tensor in _m_-dimensional space at rank _n_ is a mathematical object with components _m^n_., which obeys some rules. Thank you.

    • @FacultyofKhan
      @FacultyofKhan  Před 5 lety +12

      Thanks for the kind words! Glad you like it!

    • @danmccarron0
      @danmccarron0 Před 4 lety +19

      Yes this is a good video - feet-on-the-ground approach which is nice. But, um, no that isn't really the "actual definition" of a tensor. It is how a physicist or engineer would interpret the majority of the ones they use in their applications and rightfully so (except maybe the tensor densities). The subsequent videos deal with those rigorous definitions.
      Nonetheless this SHOULD be the starting point for introducing them, because antennas and skyscrapers are designed by real people using real equations, not created out of knowledge of differential manifolds or multi-linear spaces and typically they are brought up with those fancy-schmancy ideas in tow.
      This is good stuff here.

    • @JannikPitt
      @JannikPitt Před 3 lety +9

      This is not the definition of a tensor. It's the definition of an m by n grid of numbers.

    • @hybmnzz2658
      @hybmnzz2658 Před 3 lety +2

      @@JannikPitt emphasis on "obeys some rules"

    • @user-ry1td5uq1n
      @user-ry1td5uq1n Před 3 lety +3

      @@hybmnzz2658 Everything in math "obeys some rules", but just saying that doesn't tell anything about the particular object. That's why this kind of definition is bad: it can mean anything!

  • @Abhisruta
    @Abhisruta Před 5 lety +82

    Your digitised handwriting is beautiful...this may be a Handwriting Tensor Analysis

  • @skudzer1985
    @skudzer1985 Před 4 lety +39

    I have no idea what's going on, I just found this video in my recommended section, but I love the black background with the colored writing; it's very pleasing to the eyes.

  • @enricoiraldo9057
    @enricoiraldo9057 Před 2 lety +5

    incredibly useful. In my ignorance so far I always struggled to really find a connection between simple dimensions such as temperature and vectors, always considering them “different topics on the maths book”, but it is now clear how they are linked together

  • @isma2605
    @isma2605 Před 2 lety +1

    This is the most geometrically comprehensive explanation about TENSOR that I have seen on CZcams or books. Finally I realized why the vector's components on same direction can't be added. Thanks

  • @sihmidou9843
    @sihmidou9843 Před 2 lety

    A big thank-you ! your videos on tensors are by far the clearest and most intuitive explanations i have found on tensors !

  • @feynstein1004
    @feynstein1004 Před 4 lety +2

    Amazing introduction. I want more of these.

  • @igorxavier1544
    @igorxavier1544 Před 4 lety +1

    A phenomenal video, thank you very much for the explanation, i could finally understand what tensors really mean!

  • @maurocruz1824
    @maurocruz1824 Před 4 lety +30

    You just broke me free from YEARS and years of misconceptions about what a tensor and its rank really are . Thank you.

  • @BMerker
    @BMerker Před 4 lety +7

    Amirably clear and concise! Much appreciated!

  • @cultclassic999
    @cultclassic999 Před 4 lety +1

    Excellent intro to tensors! Thank you so much!

  • @mannathugopikrishnan9299
    @mannathugopikrishnan9299 Před 5 lety +4

    Perfectly explained. Feeling enlightened.

  • @evandrogaio7003
    @evandrogaio7003 Před 5 lety +5

    Amazing. An easy way to explain this amazing definition. Almost all students leave college without a good understand of this

    • @HighestRank
      @HighestRank Před 4 lety

      Evandro Gaio everything’s easy to the chimp which didn’t have to produce it.

  • @umedina98
    @umedina98 Před 3 lety

    Finally a video which explains tensors in an intuitive way! Excellent examples used!

  • @ahmedamr5265
    @ahmedamr5265 Před 3 lety +6

    Finally! A clear and intuitive explanation of tensors. Great job man!

  • @illogicmath
    @illogicmath Před 4 lety +2

    Thank you for this video. You are an excellent professor and communicator

  • @MeepMu
    @MeepMu Před 3 lety +7

    Thank you! You seem to be the only person on the internet who explains what a tensor is from the ground up, and actually gives a concrete example that can be followed and understood by someone who is new to the concept.

  • @joluju2375
    @joluju2375 Před 4 lety +2

    Been wondering what it was for tens of years. At last, an explanation with no bs. Thank you so much.

    • @HighestRank
      @HighestRank Před 4 lety

      Joluju no bs? It’s Sso fullll of BS that I almost don’t know where to begin. You’re brainwashed by tens of years of being sequestered, and simply suffer from a case of hostage’s-empathy. Torture you much?

  • @kshitishp3662
    @kshitishp3662 Před 3 lety

    U are the only one in my life till now I've ever seen who can explain tensors with such clarity ...u are god of teaching ...well done ...and thanks a lot

  • @JulieanGalak
    @JulieanGalak Před 5 lety +23

    Perfect timing! I just hit the point in my self-study of electrodynamics where I needed to understand tensors. Please release this series quickly! :)

    • @HighestRank
      @HighestRank Před 4 lety

      Juliean Galak granted. Oh curse my circuits a whole year late.

    • @the_sophile
      @the_sophile Před 3 lety

      Im studying this for General relativity

  • @GiI11
    @GiI11 Před 3 lety

    I'm starting an MS in physics in ablut two weeks. Your videos are perfect prep to get back into the game

  • @Gismho
    @Gismho Před 3 lety

    Thank you. This is an EXCELLENT video. All your explanations are SUPERB. I must watch all your other videos on this subject.

  • @totakuraanil2921
    @totakuraanil2921 Před 4 lety

    Many thanks for a good video, I can see the hardwork you put into editing the video.

  • @KevinKuo
    @KevinKuo Před 5 lety +52

    It's a good day when Khan releases a video

    • @HighestRank
      @HighestRank Před 4 lety

      The jester was the only other figure allowed to sit in the king’s chair.

  • @chronoyeung
    @chronoyeung Před 3 lety

    This is the best introduction of tensor i have found in YT!

  • @soumya0307
    @soumya0307 Před 4 lety +1

    Now this is something that gave me satisfaction for making me gain the intuition about tensors (Excluding the math part)

  • @absolutelynothingtoseehere

    The best intro I've seen so far. Really like the physical examples involving stress, etc. I think that section could be improved by slowing down a bit and going into explicit detail about how the physical forces are mapped to various components.

  • @NoNTr1v1aL
    @NoNTr1v1aL Před 5 lety +2

    Best video on tensors ever!

  • @alikral3149
    @alikral3149 Před 3 lety

    Great video! Thank you a million. Your pronunciation is very clear and nice along with the impeccable explanation

  • @andcool2
    @andcool2 Před 4 lety +6

    Probably the best tensor video I 've come across to date. Very elegant and crystal clear explanation of the idea of tensor, especially by bringing up real-life examples of breaking down a rectangular steel beam.

    • @HighestRank
      @HighestRank Před 4 lety

      amith anand these days a design would use what are called girders, but for complexity’s sake, a rectangular prism.

  • @jeffgalef121
    @jeffgalef121 Před 5 lety +1

    That was fantastic. Thank you!

  • @YourCRTube
    @YourCRTube Před 4 lety +3

    5:25 is why this explanation is the best - it tell you how they are used in practice!

  • @ricky12105
    @ricky12105 Před 5 lety +2

    Excellent video. Thank you!

  • @trixonx
    @trixonx Před 4 lety +8

    With this explanation even a chimpanzee can understand the concept. Very effective. One of the Best 11 mins of my life spent on CZcams!

  • @eyeballs97
    @eyeballs97 Před 3 lety

    You just explained what my teacher failed to explain in 3 90 min lectures in 11 minuites. Thank you so f****** much! :)

  • @ranitroy6495
    @ranitroy6495 Před 5 lety +3

    Outstanding....fabulous lecture ...

  • @meanymcbeik8082
    @meanymcbeik8082 Před 4 lety +1

    Perfect. Thank you.

  • @AniketSharmacodes
    @AniketSharmacodes Před 4 lety +4

    I had two questions about tensors after a lecture at my class today,
    1. Why are there 9 components and not just add resultant force to 3 component?
    2. How is Tensor different from a Matrix?
    This video answered both of these questions in a very clear and oriented manner. Thanks for understanding what students can be confused about and addressing it right in the first place.

    • @HighestRank
      @HighestRank Před 4 lety

      Aniket Sharma you’re not thinking about the same kind of tensors, sad to say.

    • @HighestRank
      @HighestRank Před 4 lety

      Aniket Sharma tensor different from a matrix. Well, a tensor isn’t a matrix but it should have one, while a matrix isn’t much like a tensor unless it’s in one. Actually that’s the best explanation I can give after an attempt at listening to billshit’s video.

    • @adam-markgheczi4577
      @adam-markgheczi4577 Před 3 lety

      @@declanwk1 I still don't "feel" the difference between them. I don't study physics or engineering, I'm just watching this video for fun. Can you explain why the forces act differently? I can't create a mental model of the scenario.

    • @declanwk1
      @declanwk1 Před 3 lety

      @@adam-markgheczi4577 sorry I don't understand it myself. If the beam was isolated (in space say) with no external forces then I would expect there to be no internal stress forces. If there was a single force acting down, I don't see why there would be shear forces since there are no components of the downward force in these directions. However beams do thin out when they get stretched, which could be indication of shear forces or just conservation of mass.

    • @adam-markgheczi4577
      @adam-markgheczi4577 Před 3 lety

      @@declanwk1 Well thanks for replying anyway

  • @IITian_shubham_shekhar_rajput

    Liked 👍 even before I started watching it...this is the level of trust I have with this channel 💕💕

    • @HighestRank
      @HighestRank Před 4 lety

      Shubham Shekhar giveitaway giveitaway giveitaway now.

  • @NancyMancarious
    @NancyMancarious Před 2 lety

    الفيديو ده شامل تقريباً جميع نواحي الموضوع، شكراً!

  • @josephlam6560
    @josephlam6560 Před rokem

    I am interested in trying to under the general relativity. In order to understand it, it sounds like one of the prerequisites is to understand tensor. For a regular guy with non-physics major, all I know is vector vs scalar. Thank you for this excellent explanation of tensor and I can understand what you are talking about.

  • @jokingseverus3221
    @jokingseverus3221 Před 5 lety +4

    The best ever explanation I have ever got about tensor.. thank you so much sir... In particular the explanation of stress tensor was the best part... how easily you told that much tough concept sir...😊

  • @PrinceKumar-fe1wr
    @PrinceKumar-fe1wr Před 4 lety +4

    Now, my tensor concept is clear. I was wondering about tensor's definition and tried to understand with many sources but failed. Thank you for the video.

    • @alphainfinitum3445
      @alphainfinitum3445 Před 4 lety

      You know very well that you are lying to yourself. This video is as terrible as all those videos and PDF that claim to introduce tensors, but rather take you into some specific application (in this case the stress tensor). At the end of the video you still don't understand tensors in general. Take it from me, if you want to safe your self years of going in circles on tensors, do the following;
      1. have a modest understanding of linear algebra.
      2. Focus on basis vectors and know how to play with them well.
      3. Study forward and backward transformation from one basis to another well.
      4. Study covectors well.
      5. Study the tensor product well.
      6. Then at this stage you will not only know what a tensor is, but you will have a working knowledge of tensors. So you will be able to pick up a book on tensor calculus and follow through well.
      Good luck and thank me later.

  • @ChocolateMilkCultLeader

    One of the best channels for math out there.

  • @tareqal-ghamdi1349
    @tareqal-ghamdi1349 Před 4 lety +2

    The greatest Tensor’s video ever

  • @Martin-iw1ll
    @Martin-iw1ll Před 5 měsíci

    Great video for giving an intuitive understanding of tensors

  • @curlyconstant
    @curlyconstant Před 5 lety +2

    Thank you so much this helped a lot🙏🙏

  • @TheTranq
    @TheTranq Před 4 lety +1

    Very helpful and no bs. Thank you

  • @mehedihassan8649
    @mehedihassan8649 Před 3 lety

    This is gold! Thank you so much

  • @abdulmalekwalayeh4790
    @abdulmalekwalayeh4790 Před 5 lety +1

    What a great explanation!!

  • @richardneifeld7797
    @richardneifeld7797 Před 2 lety

    Nice clear and simple introduction to the topic.

  • @jameswood8999
    @jameswood8999 Před 4 lety

    Looking forward to the next video. What I'm looking for, is looking for Einstein's application of curvilinear coordinates and using tensor calculus to solve general relativity

  • @fitness60plus52
    @fitness60plus52 Před 7 měsíci

    wow! the best (because VISUAL) explanation of tensors, so different from the usual, axiomatic definition.

  • @timothyvaher2421
    @timothyvaher2421 Před 4 lety

    Completely realized this lesson. A concise understanding is communicated. Education is happening here: Khan Academy is a towering success!

  • @cybertronian9909
    @cybertronian9909 Před 5 lety +6

    Damn, nice visuals and explanations as always

  • @lucys3482
    @lucys3482 Před 4 lety +7

    Excellent video. I love the beam example, as it puts the concept into a real world problem. You clearly have a charisma in passing on your knowledge. Not many have the 'touch of Feynman'. :) Thank you for doing this!

  • @RyanLBuchanan
    @RyanLBuchanan Před 3 lety

    Brilliant! Thank you soooo much! Now I understand!

  • @jurascipakre9200
    @jurascipakre9200 Před rokem

    Best explanation on youtube, thank you.

  • @ankurc
    @ankurc Před 5 lety +1

    very simple and clear thanks

  • @lunacui461
    @lunacui461 Před rokem

    Thank you SO MUCH!!!

  • @ibanix2
    @ibanix2 Před 2 lety

    jesus christ, this was the video I needed. Simple, concise, perfect illustrations.

  • @rachanasoni007
    @rachanasoni007 Před 5 lety +4

    Your voice and fluency are 😍

  • @hendriaditjandra6418
    @hendriaditjandra6418 Před 4 lety +1

    Thank you Sir for a very clear explanation.

  • @prashanttripathi2211
    @prashanttripathi2211 Před 2 lety

    Thank you so much sir. Wonderful explanation

  • @serahstales9451
    @serahstales9451 Před 4 lety +2

    Thank you so much sir🙏🙏

  • @MathwithMunaza
    @MathwithMunaza Před 3 lety +1

    Best explanation on this topic.

  • @thomasanderson1416
    @thomasanderson1416 Před 4 lety +3

    FINALLY! Thanks.

  • @rp1455
    @rp1455 Před 5 lety +7

    Thanks for just giving it straight. This was a much more helpful explanation than others who used fancy graphics or kids toys.

  • @eoinmullally1531
    @eoinmullally1531 Před 5 lety +2

    Great Video! Very neat and easy to understand!

  • @ezu8501
    @ezu8501 Před 4 lety +1

    great job! beautifully done. and your digital handwriting

  • @NovaWarrior77
    @NovaWarrior77 Před 3 lety +1

    LITERALLY AWESOME.

  • @soumahakase7124
    @soumahakase7124 Před 3 lety

    You are a bless man, thank you very much.

  • @ParasiteDelta
    @ParasiteDelta Před 4 lety

    You melted my brain, but it's still very interesting. Well done.

  • @nargis7646
    @nargis7646 Před 3 lety

    Great explanation...Thank you

  • @gunaycafarova750
    @gunaycafarova750 Před 3 lety

    Thank you for this video , I think it will help me in my speech about Tensors✨

  • @mokshraj63
    @mokshraj63 Před 2 lety

    I really wanted to have this lecture thank you sir pls add more videos of
    Physics 💙

  • @wdobni
    @wdobni Před rokem

    this guy is a TEACHER ..... very good video that reduces tensors to reasonable ideas for simple minds like mine

  • @Abhisruta
    @Abhisruta Před 5 lety +4

    Very good video... All concepts are clear

  • @amitshoval7653
    @amitshoval7653 Před 2 lety

    Thanx for an this amazing explenation!

  • @gerardomoscatelli8584
    @gerardomoscatelli8584 Před 4 lety +1

    Amazing explanation tks

  • @rahuldas4967
    @rahuldas4967 Před rokem +1

    Shit this 4 year old content is much better than all the videos I watched on Tensors till now ❤️😍

  • @kewal_chhetri
    @kewal_chhetri Před 3 lety

    Very nice introduction to tensors... Impressive.... Explained in a very fundamental way

  • @PunmasterSTP
    @PunmasterSTP Před 2 lety

    This is hands-down the best explanation of tensors that I have ever seen or read. I can't tell you how much time I have spent in different places looking at different things and still not understanding the essential concepts. Thank you so so much for making these videos and putting them up, and I'm planning to binge-watch them in my free time!

  • @infinitylove2713
    @infinitylove2713 Před 5 lety +4

    Nice lecture.......keeeep doing .....it will help a lot ..thank you sir

  • @GandalfTheBrown117
    @GandalfTheBrown117 Před 4 lety +1

    Very well made video. I like the script and examples and the figures were drawn very well. Thank you for this.

  • @sindbadthesailor1541
    @sindbadthesailor1541 Před 5 lety +3

    Great video!!

  • @ErickFGx
    @ErickFGx Před 3 lety

    Thank you!

  • @JoseAntonio-ml8yg
    @JoseAntonio-ml8yg Před 2 dny +1

    ¡Gracias!

  • @fmp1976
    @fmp1976 Před rokem

    Great lecture, thank you

  • @Zeezoro
    @Zeezoro Před 3 lety

    Best video. Thank you

  • @Gabby-du4mc
    @Gabby-du4mc Před rokem

    You are a blessing!!!!

  • @mrozzy4442
    @mrozzy4442 Před 3 lety

    Very helpful - thank you!

  • @hankli6968
    @hankli6968 Před 3 lety

    the best video on tensors!

  • @rfzafar
    @rfzafar Před 2 lety

    The insight for tensors was amzaing, i was struggling to solve a problem which included gradient of exponential function in matrix variable.

  • @user-te4jj2nq6q
    @user-te4jj2nq6q Před 3 lety

    Very nice.
    Thank you 😊

  • @karthick...
    @karthick... Před rokem

    Thank you ❤️

  • @zubairahmad655
    @zubairahmad655 Před 4 lety

    Thanks a lot sir. U have solve my a lot of my problems..

  • @somefuckstolemynick
    @somefuckstolemynick Před 5 lety +2

    Great video! Thanks!