The reason for Quantum Mechanics - Part 3 of 3

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  • Опубликовано: 21 дек 2024

Комментарии • 85

  • @DrPhysicsA
    @DrPhysicsA  11 лет назад +2

    I think you mean the double slit experiment done by Young using light. D&G essentially repeated the experimental approach but using electrons. Instead of a double slit they essentially used a diffraction grating which was a crystal. The gaps between atoms essentially make up the slits.

  • @DrPhysicsA
    @DrPhysicsA  12 лет назад +2

    The idea is that an electron which behaves like a standing wave has a whole number of wavelengths as part of its orbit. It is quantised. Schrodinger developed the maths to show that electrons behaving like waves are constrained to have only certain energy levels and this prevents them spiraling in .

  • @DrPhysicsA
    @DrPhysicsA  11 лет назад +3

    Starting from E=pc we get p=h/λ. As you say, all to do with light. But Einstein had shown (photoelectric effect) that light as well as being a wave was also a particle (photon). That caused a French physicist, de Broglie, to speculate that an electron (a particle) might also behave like a wave and if so, might obey the same equation where p would now be mv, not mc. Experimentally verified.

  • @dblockbass
    @dblockbass 12 лет назад +1

    It's so fascinating how some theories, deductions and extrapolations were drawn from a long line continuous line of research. I will always appreciate the logical industriousness of science. You expound on this very well too. Thanks!

  • @thaisfrutu7
    @thaisfrutu7 9 лет назад +16

    Hey. I want to say thank you! The way your explain these phrenomenon is utterly brilliant!!

  • @DrPhysicsA
    @DrPhysicsA  11 лет назад +2

    Yes. Because n is an integer so angular momentum is quantised.

  • @Lee_yourboylee
    @Lee_yourboylee 10 лет назад +3

    Great teaching. Connected together sequentially and explained as simple as it can be but no simplier. Thank you Dr.

  • @zaphodbeeblebrox8496
    @zaphodbeeblebrox8496 11 лет назад +8

    Thank you so much. Your have filled in so many blanks for me. Your ability to communicate the relevant information is outstanding.

    • @DrPhysicsA
      @DrPhysicsA  11 лет назад +4

      Thank you for your very kind comments.

    • @FullMoongrn
      @FullMoongrn 11 лет назад +1

      DrPhysicsA I admire extremely your way of explanation. If I was a rich man I would have come to you and followed private courses and payed you any price you like. Keep up doing this good work. You are a gift mr Eagle.

  • @DrPhysicsA
    @DrPhysicsA  11 лет назад +1

    Now that's a good question. If we both participate in the experiment, but you look inside the box but I dont does the wavefunction collapse for you but not for me. The strict answer is that before either of us look the particle is in a superposition of states. Once you look the wavefunction collapses. I am simply in a state of ignorance till I look, or ask you.

  • @solematedesign
    @solematedesign 11 лет назад +1

    your videos are great for revision and really break the monotony of revising form text books! thank you

  • @havehalkow
    @havehalkow 11 лет назад +6

    Sir, you make physics seem so easy and beautiful, thanks a lot ! )

  • @felixbako
    @felixbako 10 лет назад +1

    Great work .You make it so easy to understand.

  • @DrPhysicsA
    @DrPhysicsA  11 лет назад +2

    That shouldn't be the case. My five-part series on special relativity calculates the relativistic momentum P.

  • @uquantum
    @uquantum 4 года назад +1

    Thanks DrPhysicsA for this wonderful introduction to quantum mechanics, and for the other entertaining and informative videos you’re sharing with the world

  • @donjosue1000
    @donjosue1000 11 лет назад +1

    you have explained things very well and have made them very easy to understand, good job

  • @ufotofu9
    @ufotofu9 9 лет назад +6

    Best metaphor for the Photoelectric Effect is in Brian Green's "The Elegant Universe." I hope I can do it justice.
    So the metaphor got like this: Imagine that a room is filled with children. There is one doorway out of the room, which is guarded by a bouncer who will only let the children out if they pay him $1.
    Above the children are adults who are standing on a catwalk. The adults want to get the children out of the room, and so they begin throwing Nickels, Dimes and Quarters down at the children, hoping that any one child will be able to collect enough change to buy pay the $1 fee to leave the room.
    In this metaphor, the children are the Electrons on the surface, and the coins are the Photons. The bouncer is what allows the Electron/children to be released, but only with the required whole number of $1. Fractions of a dollar are not allowed, just as Quantum Numbers must be whole numbers.
    Following along, It doesn't matter how hard that the change is thrown (intensity). With so many Electron/children, it is unlikely that any one child will be able to collect enough change to pay the $1 fee and get released. But if the adults start throwing down dollar bills, now everybody only needs to collect one denomination being thrown at them, as opposed to the many denominations needed when the coins were thrown. Now the Electron/children are being released in large amounts.
    Obviously, the dollar bills being thrown down is analogues to the lights frequency. It did't matter how intensely (how fast) the coins were thrown at the children. It was unlikely for any one child to collect a dollar out of the coins. But the dollar bills don't need to be thrown intensely to release the children. The bills just need to be the correct amount, and off the Electron/children go.
    Does that all make sense?

  • @christopherwatts5055
    @christopherwatts5055 11 лет назад +1

    great video, by far the most informative.

  • @augurelite
    @augurelite 8 лет назад +1

    So informative and well presented!!!!

  • @CHEESYhairyGASH
    @CHEESYhairyGASH 10 лет назад +2

    absolutely fantastic
    thank you for taking the time to enlighten us all.

  • @pufalupagus
    @pufalupagus 11 лет назад +1

    Could you please do a video giving a basic introduction on string theory?

  • @philippeudry6818
    @philippeudry6818 7 лет назад +1

    Great work you can explain this so good that also i understand this. Thank you soooo much.

  • @omarali7572
    @omarali7572 9 лет назад +1

    thank you so much for this amazing videos
    but why u didnt mention Bohr

  • @JulianLagrange
    @JulianLagrange 9 лет назад +3

    Thank you for teaching! What a great (free!) gift to the rest of us :)

  • @dan69052
    @dan69052 11 лет назад +1

    As a chemistry teacher, I must say that these are great presentations. Peace

    • @DrPhysicsA
      @DrPhysicsA  11 лет назад +1

      I am most grateful. Thanks.

  • @TheGodlessGuitarist
    @TheGodlessGuitarist 6 лет назад +1

    Wonderful explanation. Thank you kindly.

  • @stasSS5
    @stasSS5 11 лет назад +1

    im just an avrege high school student and i got to say i realy enjoy your videos great video!

  • @larryhernandez5062
    @larryhernandez5062 7 лет назад +1

    Another great video by are British friend DrPhysicsA . Sincerely Larry Hernandez . THANKS

  • @DrPhysicsA
    @DrPhysicsA  11 лет назад +1

    Better to say it behaves like a wave rather than that it is a wave. Wave characteristics help us explain the world of quantum mechanics. But my best advice is not to try to understand it by reference to classical mechanics. It's a different world.

  • @teetee1640
    @teetee1640 11 лет назад +1

    You make it so simple! Thank you so much!

  • @alisaleh1900
    @alisaleh1900 6 лет назад +1

    Very simple and clear .. thanks a lot

  • @raifsam3408
    @raifsam3408 11 лет назад +1

    sorry for interrupt.. do you mean the angular momentum is conserved with the formula p=nhbar?

  • @joeldogadams3895
    @joeldogadams3895 11 лет назад

    I have a question about the physical interpretation of waves, specifically electromagnetic waves. As to my understanding a wave is an oscillating electromagnetic field that oscillates in one dimension (simply up and down) usually many waves are present causing oscillation at all angles. Via this interpretation what exactly is the difference between the electromagnetic field that the waves pass through and the "aether" as tested by michelson and morely?

  • @santoshmahato8032
    @santoshmahato8032 7 лет назад

    it helps to improve my knowledge thanks a lot, but second problem about proton stability not explain yet

  • @pufalupagus
    @pufalupagus 11 лет назад +1

    Great job

  • @vaughne4712
    @vaughne4712 11 лет назад

    Great video! School should teach more like this, so you understand where things come from and why they are important. This video series for me helped me understand how all these "random" things I learned in school are actually tied together. Thanks!

  • @pegatrisedmice
    @pegatrisedmice 11 лет назад

    this is great, simple explanation! thank you! but i just don't get the concept of wave...can a single particle be a wave?

  • @AlOufiHussain
    @AlOufiHussain 11 лет назад

    Thank you very much, l like your work. You make it clear and simple to understand. Please, keep going

  • @1998anirudh
    @1998anirudh 11 лет назад

    This deserves more views !

  • @comprehensiveboy
    @comprehensiveboy 11 лет назад

    I think were at a similar stage. Radio waves are going outwards too or they would not have velocity = c. They travel through 'empty' space. Standing waves just go up and down, I think that's what an electron does when you think of it as a wave. I think the equations are easier to understand than trying to get an intuitive picture. The best I can do is move my finger up and down regularly while moving it front of my face.

  • @relhage100
    @relhage100 11 лет назад +1

    great videos thank you!

  • @christopherwatts5055
    @christopherwatts5055 11 лет назад

    question on the observer effect, who's the observer just humans or can animals like a cat make the wave collapse into a particle? Also is it the devices they use for measuring the particles causing the collapse, possibly or just the measuring itself? One last thing how do they know waves collapse into particles when observed considering you wouldn't know what it was when your not observing? I've been trying to understand this and have done alot of research but these questions aren't clear to me.

  • @sathishshastry461
    @sathishshastry461 10 лет назад

    so simple sweet explanation....... thank you very much 'SIR'

  • @PrasauskasPaulius
    @PrasauskasPaulius 11 лет назад

    Hello, you said, that p = mv, but Einstein in special relativity corrected this equation to p = mv / lorentz_factor. I`ve done that calculation and i found that then p then is always 0 .

  • @adam157reloaded
    @adam157reloaded 12 лет назад +1

    Thanks dude this is so interesting

  • @dogwithwigwamz.7320
    @dogwithwigwamz.7320 9 лет назад +1

    Amazing.

  • @eruiluvatar6688
    @eruiluvatar6688 5 лет назад

    But isnt E=mc^2 derived from E^2=(mc)^2 + (cp)^2 where p=0? Thus why can it be said that p=E*c/c^2

  • @jayz12321
    @jayz12321 12 лет назад

    i don't understand
    why electrons behave like waves and atom have certain energy level can get the conclusion that electron would not spiral into the neucleus?

  • @rohitabraham5809
    @rohitabraham5809 11 лет назад +1

    Brilliant

  • @strikeblade6669
    @strikeblade6669 4 года назад

    didn't planck discovered E=hf?

  • @obayrafi2632
    @obayrafi2632 6 лет назад

    Good explanation

  • @koithecatgamer
    @koithecatgamer 12 лет назад +1

    do like it man

  • @priyankagunjan7887
    @priyankagunjan7887 4 года назад

    Very good vedio

  • @ayatelrahmanelsayed5890
    @ayatelrahmanelsayed5890 8 лет назад

    why because electron behave like wave that forces it to stay at specific orbits without attracked to nucleus and destroy atom ?!

    • @DrPhysicsA
      @DrPhysicsA  8 лет назад +2

      Because the wave like nature of the electron means it can occupy only certain quantised energy levels. It is thus forbidden from spiralling in.

  • @Cube8
    @Cube8 11 лет назад

    You didn't explain why we have finite max number of electrons per level around the nucleus. Also, you didn't explain what is the role of the neutrons inside the nucleus.

    • @AayamS
      @AayamS 11 лет назад

      those are basic ideas, just google it. also look on the fundamental forces. might help

  • @eaglewolfzen
    @eaglewolfzen 10 лет назад

    except in nuclear reactions. the explosion compresses the atoms so the electrons actually get into the nucleus. and thats not even counting tunneling.

  • @jackpipe68
    @jackpipe68 4 года назад

    This was excellent throughout, but I feel you bungled the punchline. Why should the fact an electron behaves like a wave mean that it can only occupy certain energy levels? I see in your other videos that you draw electrons as a circular standing wave around the nucleus, and this gives a very intuitive explanation for why there are levels; there needs to be a whole number of wavelengths. Why not use that device here?

  • @Vide0Browser
    @Vide0Browser 11 лет назад

    idk exactly how many experiments scientists did to propose such extraordinary claims, but for them to invent a whole new counter intuitive universe I hope they have done enough experiments.

  • @sanGuziy
    @sanGuziy 11 лет назад

    m there already contains the Lorenz factor m=m0/lorenz-factor.

  • @johnmiller5259
    @johnmiller5259 6 лет назад +1

    😊🙏

  • @iKhazModan
    @iKhazModan 11 лет назад

    Thank you

  • @mettlus
    @mettlus 11 лет назад

    Amit Goswami explains it quite simply, look for him in youtube

  • @1998anirudh
    @1998anirudh 11 лет назад

    just a sec .. while deriving g p = h/ lambda you made an assumption that v = c , in the case of light that is true . But then you go on the say lambda = h / mv , that should have been h /mc . A little help some one ?

  • @Linshark
    @Linshark 11 лет назад

    You left out Niels Bohr..

  • @erwinmeza2826
    @erwinmeza2826 6 лет назад

    it explanation well

  • @mettlus
    @mettlus 11 лет назад

    Please watch Amit Goswami, he has answers to all your questions!

  • @profeluisegarcia
    @profeluisegarcia 3 года назад

    ¡¡BRAVO¡¡¡¡

  • @jacobvandijk6525
    @jacobvandijk6525 11 лет назад

    I agree. Great video's! BUT why is the order of your video's so messy.

    • @DrPhysicsA
      @DrPhysicsA  11 лет назад +1

      Not sure what order you are looking at. The main list is just the order they were uploaded. But the playlists put the videos into categories and within each playlist the videos should be in some logical order.

    • @jacobvandijk6525
      @jacobvandijk6525 11 лет назад +1

      DrPhysicsA I'm sorry. You're right.

  • @allenrobinson5750
    @allenrobinson5750 11 лет назад

    i feel like i just went on a journey.

  • @adnansaud3194
    @adnansaud3194 11 лет назад +1

    #RESPECT SIR! :)

  • @ClubCarambaGuitar
    @ClubCarambaGuitar 8 лет назад

    I would rather say that they are neither particle nor wave.....

  • @ParijatMohajan
    @ParijatMohajan 3 года назад

    And the reason why we all exit

  • @ShirtOffLJay
    @ShirtOffLJay 12 лет назад

    excellent. now i'm only 80% lost. think i have a learning disorder

  • @cadkls
    @cadkls 11 лет назад +1

    You say that C over f is the wavelength, but the formula is f over C. Let's say f is 1 and C is 10, C over f is 10, but f over C is 0.1.
    10 does not equal 0.1
    Therefore the equation is wrong.

    • @DrPhysicsA
      @DrPhysicsA  11 лет назад +5

      The speed of the wave is its frequency multiplied by its wavelength.

  • @Vide0Browser
    @Vide0Browser 11 лет назад

    science is formed on shaky grounds...

  • @OmarGhanemAbdelrady
    @OmarGhanemAbdelrady 6 лет назад

    ruclips.net/video/1vWWbsveQKo/видео.html
    hahah
    de broglie nailed it