This experiment confirmed quantum energy levels

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  • Опубліковано 10 вер 2024
  • Buy me a coffee and support the channel: ko-fi.com/jkzero
    In this video, we dive into the details of how the Franck-Hertz experiment provided the first direct evidence of quantized energy levels in atoms, confirming key aspects of Niels Bohr's atomic model.
    [Erratum]
    04:50: cos(θ) inside the square root should be sin²θ; thanks to ‪@jmmahony‬ for catching this typo.
    [Related videos]
    ∘ Film: the Franck-Hertz experiment, Physical Science Study Committee (1961) archive.org/de...
    ∘ The Birth of Quantum Mechanics • The Birth of Quantum M...
    ∘ This effect confirmed light particles • This effect confirmed ...
    ∘ Millikan tests Einstein's Light Theory • Millikan tests Einstei...
    ∘ How Niels Bohr created the quantum atom • How Niels Bohr created...
    ∘ This star almost broke Bohr's atomic model • This star almost broke...
    ∘ Playlist video series on Quantum Physics • Quantum Mechanics
    [References]
    ∘ J. Franck and G. Hertz, Über Zusammenstöße zwischen Elektronen und Molekülen des Quecksilberdampfes und die Ionisierungsspannung desselben, Verh. Dtsch. Phys. 16: 457 (1914)
    ∘ N. Bohr, On the constitution of atoms and molecules, London Edinburgh Philos. Mag. & J. Sci. 26, 151: 1 (1913) archive.org/de...
    [Credits]
    Heinrich Hertz, public domain
    Heinrich Hertz discovering radio waves, public domain
    Phillipp Lenard, public domain
    Gustav Herz, public domain
    James Franck, public domain
    Stanford Linear Accelerator, by P. Kaminski, public domain
    Electron-proton deep inelastic scattering, by Ddn2 under CC BY-SA 3.0
    Tube for Franck-Hertz experiment, by 3B Scientific amzn.to/4fDM6OZ
    Hans Geiger, public domain
    Ernest Marsden, public domain
    Ernest Rutherford, public domain
    Arthur H. Compton, public domain
    Ping-pong ball, by I. Joseph free use via Pexels www.pexels.com...
    Bowling ball, by A. Shvets, free use via Pexels www.pexels.com...
    Franck Hertz experiment, by 老陳 under GNU Free Documentation License V1.2
    Franck-Hertz experiment with neon gas, Infoczo/MikeRun as CC BY-SA 4.0
    Subway station, by Sosa Films, free use via Pexels www.pexels.com...
    Fluorescent lights, by KoolShooters, free use via Pexels www.pexels.com...
    Tanning lamp, by D. Brown, public domain
    Tanning lamp filament, by D. Brown, public domain
    Franck-Hertz experiment
    CC BY-SA 3.0: creativecommon...
    CC BY-SA 4.0: creativecommon...

КОМЕНТАРІ • 318

  • @douglasstrother6584
    @douglasstrother6584 26 днів тому +42

    It's fascinating how much Physics was squeezed out of vacuum tubes containing various configurations of high-voltage electrodes and a variety of gasses (or a vacuum).

    • @jkzero
      @jkzero  23 дні тому +11

      Totally agree, it is remarkable that the same few components cleverly arranged in different ways in tabletop experiments unveiled so much new physics over 100 years ago.

    • @futureconsequence5374
      @futureconsequence5374 11 днів тому +2

      IKR! Humans are awesome!

    • @anteconfig5391
      @anteconfig5391 6 днів тому +2

      for real

    • @caustinolino3687
      @caustinolino3687 4 дні тому +1

      ​@@jkzero It's also amazing how much progress has slowed since then.

  • @novakonstant
    @novakonstant 28 днів тому +58

    Best physics channel on youtube.

    • @jkzero
      @jkzero  26 днів тому +5

      Thanks for that, it is very moving when viewers appreciate the content and the effort to produce it.

  • @zephyrandboreas
    @zephyrandboreas 28 днів тому +68

    Beautiful and clear presentation. Amusing to see how self-deprecating James Frank was about keeping up with the literature in the field ('you know how that happens'... 😅 ). Brings memories of my Friday afternoons spent, with other colleagues, trying to catch up with the literature (when everything was in paper 😊).

    • @jkzero
      @jkzero  26 днів тому +6

      Thanks for watching until the end, having that record of Franck describing his own historic experiment is just fantastic. That added to his humble and shy personality adds extra value.

  • @pedrowojciechowski8669
    @pedrowojciechowski8669 26 днів тому +15

    Interviewer: How good are you in what you do?
    Hertz: Yes

  • @mikemcguire1160
    @mikemcguire1160 27 днів тому +12

    I remember doing this experiment as an undergraduate. The tricky part was getting the temperature of the tube right. We messed with if for a couple of hours and then suddenly it came right and with a few minutes we got beautiful result of four or five peaks 4.9 volts apart--very gratifying.

    • @jkzero
      @jkzero  26 днів тому +2

      Thanks for sharing, yeah, I remember vividly this experiment in particular from my undergrad days, it really changed my way of seen the theory and valued these clever but, but today's standards, quite simple experiments.

    • @mellertid
      @mellertid 11 днів тому

      What happens when the temperature is too low or too high?

    • @mikemcguire1160
      @mikemcguire1160 11 днів тому +1

      @@mellertid The density of the mercury vapor varies with temperature

  • @carlosanvito
    @carlosanvito 27 днів тому +13

    As an electrical engineer, I can see regions of negative impedance in the experiment. Thank you for your excellent presentation.

    • @jkzero
      @jkzero  27 днів тому +2

      Thanks, I am glad you like the content

    • @MadScientist267
      @MadScientist267 25 днів тому +1

      I'm curious how this relates over to the crookes dark space in a discharge tube.

    • @jkzero
      @jkzero  24 дні тому +2

      @@MadScientist267 to be honest, I didn't know about Crookes' dark space, I had to look it up. Just from a quick search, the dark spaces observed by Crookes and Faraday appear to be due to large pressure differences. But I would need to read more to provide a better answer.

    • @MadScientist267
      @MadScientist267 24 дні тому +2

      @@jkzero I'd need to do the same but I'm thinking that the idea of pressure differences in an operating tube would have to be caused by these collisions... places where the gas is being displaced by the forces the electrons put on it... distance from the cathode dependent on the potential required in that zone to reach that first bump...

    • @victorscarpes
      @victorscarpes 20 днів тому +1

      Yeah, reminds me of tunnel diodes

  • @MaximumBan
    @MaximumBan 28 днів тому +28

    There is a huge gap between knowing the results of the experiment and understanding why you've got these results.

    Epic video. Best of many science videos I saw in the last two years!
    🎉🎉🎉❤❤❤

    • @jkzero
      @jkzero  27 днів тому

      Thanks for your kind message

  • @thomasgargan5971
    @thomasgargan5971 21 день тому +4

    Hands down most amazing physics video series on youtube.
    I’m a second year physics student and I have never seen such a good mathematical and experimental explanation.
    I rarely comment on videos, but this is the best video I have seen in ~5 years of watching content like this. Please keep it up.

    • @jkzero
      @jkzero  19 днів тому

      Wow, thank you! I really appreciate your positive feedback. I am totally with you. When I was a physics student I learned the solutions to the problems of the time but I remember that the lack of context and details was quite unsatisfactory. I decided to dig deeper, read parts of the original papers, and I decided to share the details and get the record straight. I think that the stories get even more fascinating.

  • @jaredhouston4223
    @jaredhouston4223 28 днів тому +16

    This was my first time viewing one of your videos and I have to say your content looks like it took some hard work, but you obviously love what you're doing and that combination instantly made me subscribe.
    Thank you for this video!

    • @jkzero
      @jkzero  27 днів тому +3

      Thanks for sharing, I really appreciate your kind words. Yes, it is a lot of work putting these stories to write and produce so thanks for the appreciation and welcome to the channel, make sure to check the other videos

    • @Erufailon.83
      @Erufailon.83 24 дні тому

      Same for me. It was my first video of this channel and as soon as it ended I liked and subscribed instantly.

  • @mktwatcher
    @mktwatcher 28 днів тому +12

    Excellent Summary of the Franck-Hertz Experiment and how it confirmed Bohr's Theory of the Atom and specific energy level shells.

  • @coolcat23
    @coolcat23 27 днів тому +5

    Indeed a beautiful experiment. I'm touched by the humility shown by Franck at the end of the clip. Einstein had a similar soft-spoken attitude. Nowadays, the en vogue personality is loud, bold, and hyper confident. I miss these classic personalities.

    • @jkzero
      @jkzero  26 днів тому +2

      Thanks for watching until the end, having that record of Franck describing his own historic experiment is just fantastic. That added to his humble and shy personality adds extra value.

  • @lastchance8142
    @lastchance8142 27 днів тому +6

    Thank you for producing such a comprehensive and clear description of this experiment...especially including the relevant equations!

    • @jkzero
      @jkzero  27 днів тому +1

      Thanks, I am glad you liked it. The niche of this channel is a mix of historical context, some calculations, and use of original sources (original papers) and the viewers have actively asked me to include calculations instead of just superficial stories.

  • @uploadJ
    @uploadJ 20 годин тому +2

    I love basic, primary experiments. Too many presenters present 'thought experiments', which have their place, but are no substitute for actual lab experimentation. Thank you Dr. Diaz for the video.

    • @jkzero
      @jkzero  17 годин тому +1

      I am glad you like the content. I am totally with you, thought experiments have their place in physics, but the real magic happens with real experiments, with real measurements, and really shocking results. More of that coming soon.

  • @abdou.b3259
    @abdou.b3259 28 днів тому +12

    Please make a video for us about the books that helped you in the field of physics and mathematics for beginners

    • @jkzero
      @jkzero  27 днів тому +7

      I have on my to-do list a video on book recommendations, I will make sure to have it before the holiday season

  • @TheMusicPerson
    @TheMusicPerson 28 днів тому +11

    Wonderful as always. Your videos are some of my favorite on UA-cam. Thank you for doing what you do!

    • @jkzero
      @jkzero  27 днів тому

      thanks for your kind words, I really enjoy making these videos so it is great to see that they are appreciated

  • @4kevbot3
    @4kevbot3 28 днів тому +6

    I really enjoy your channel. I’m an out of practice engineer (ie. lost my knack for physics after working in Project Controls/Admin). Keep the videos coming! Bravo!

    • @jkzero
      @jkzero  27 днів тому

      thanks for watching, great having you here

  • @jimsvideos7201
    @jimsvideos7201 28 днів тому +6

    Thank you for an elegant explanation for such an elegant discovery.

    • @jkzero
      @jkzero  27 днів тому +1

      a lovely experiment, I really like how these table-top experiments really transformed our way of thinking

  • @darkmedici
    @darkmedici 28 днів тому +4

    I agree, this is an exceptional demonstration and explanation of this experiment.

  • @pAO29Ex
    @pAO29Ex 24 дні тому +2

    Thank you, sir. I finally can understand what the corresponding section in my quantum mechanics textbook about the Franck-Hertz experiment is actually trying to explain.

    • @jkzero
      @jkzero  24 дні тому +1

      I am glad it was helpful, what quantum-mechanics textbook are you following?

  • @Paul-ty1bv
    @Paul-ty1bv 28 днів тому +3

    I watched the other video. They busted out a slide rule. I loved it. Thanks for the recommendation.

    • @jkzero
      @jkzero  27 днів тому +1

      I am glad you watched that, I also found the use of the slide rule fascinating

  • @lepidoptera9337
    @lepidoptera9337 6 днів тому +2

    We had a century's worth of spectroscopic data that showed quantized energy levels. People simply didn't know what to make of it.

  • @mylittleelectron6606
    @mylittleelectron6606 4 дні тому +1

    I really love the work you're doing. It is the apotheosis of popular science content online.

    • @jkzero
      @jkzero  4 дні тому

      thanks, I am so delighted that viewers enjoy the content as much as I enjoy making it

  • @msontrent9936
    @msontrent9936 22 дні тому +2

    Extremely good video. You have a gift of making things simple to digest. I understood everything at first watch. Thanks for sharing.

    • @jkzero
      @jkzero  22 дні тому +1

      Thanks for your kind comment. I am glad the content can be followed. I really enjoy explaining these things and I miss teaching at universities so this channel gave the opportunity to share all these stories.

  • @robertharper3057
    @robertharper3057 28 днів тому +3

    fantastic as always. brought back the same memories of performing it in undergraduate school and then teaching it in graduate school, i sent you some coffee :)

    • @jkzero
      @jkzero  27 днів тому

      Thanks so much for your generous support. This is an experiment that really got me talking about it for weeks when I did it during my undergrad.

  • @mernokimuvek
    @mernokimuvek 4 дні тому

    As a nerd with a hobby of electronics, I absolutely love fluorescent lamps. I even collect old discarded ones. Even if the cathodes are broken, if the seals are intact they will light up without wire near a Tesla coil.

  • @anteconfig5391
    @anteconfig5391 6 днів тому

    When I saw that old footage of the experiment my heart fluttered and my jaw dropped because I recognized that this was a desktop experiment showing proof of quantization being a reality, and it was so easy to understand. Sure, I read the title of the video and that's why I clicked the link but I was so captivated by this entire video that I forgot why I was here.
    I love physics.

    • @jkzero
      @jkzero  5 днів тому

      I get your point, I really got goosebumps when I did this experiment with my own hands, memorable moment.

  • @leon1111er3
    @leon1111er3 28 днів тому +5

    Nice coincidence. I Was studyikg the Franck Hertz Experiment today

    • @jkzero
      @jkzero  28 днів тому +3

      spooky action at a distance?

    • @leon1111er3
      @leon1111er3 28 днів тому +2

      I assume ;)

    • @mellertid
      @mellertid 11 днів тому

      Avoid the environment until the exam, you don't want to lose coherence.

  • @Necrozene
    @Necrozene 27 днів тому +5

    I guess Stein was busy that day, and Hertz got his day in the sun.

    • @jkzero
      @jkzero  27 днів тому +1

      I have to be honest, only after the recording of the story I realized that many times I said Franck-and-Hertz way too fast

    • @raycar1165
      @raycar1165 3 дні тому +1

      Is this a The Far Side reference?!

    • @Necrozene
      @Necrozene 3 дні тому +1

      @@raycar1165 It may well be! Thank you for amplifying the joy. Wonderful! Great things surround greater things.

    • @jkzero
      @jkzero  2 дні тому

      @@raycar1165 no idea what The Far Side is, I would have to google it

    • @raycar1165
      @raycar1165 День тому

      @@jkzero The Far Side is an art/comic series by Gary Larson.
      Known for his very simple, one image storytelling.
      “I guess Stein was busy that day, and Hertz got his day in the sun”
      Sounded like it could have been one of the captions.

  • @smartperson1
    @smartperson1 25 днів тому +1

    What a delightful explanation thank you. That was a fun experiment. And your explanation of it is straightforward enough for me to share with my nephew in high school, while also demonstrating the mathematics.

    • @jkzero
      @jkzero  24 дні тому

      Thanks fro your positive feedback and for sharing. This part of the early times of quantum physics are remarkably simple in terms of mathematical complexity. The whole Bohr model can be derived with just high-school physics.

  • @JamesKaramath
    @JamesKaramath 23 дні тому +1

    Just discovered your channel through this - wow! I'll be using this as challenge material for my students going forward, thanks so much, will check out your others too

    • @jkzero
      @jkzero  22 дні тому

      Thanks for your kind comment. One of the most satisfying outcomes of creating content for this channel has been the great number of people telling me "I am showing your videos to my students." I hope you enjoy the rest of the series and welcome to the channel!

  • @barry7608
    @barry7608 17 днів тому +1

    Brilliant I’m not overly bright but could follow that, not the formula’s, but the process and its implications, very well explained thanks

    • @jkzero
      @jkzero  17 днів тому

      Glad it was helpful! Don't put yourself down, this is definitely not trivial stuff and a little secret: the math is the easy part, the concepts are really the hard component of quantum physics so you might be more advanced than you give yourself credit for.

    • @barry7608
      @barry7608 16 днів тому

      Thank you very kind

  • @AlphaPhoenixChannel
    @AlphaPhoenixChannel 24 дні тому +2

    Is the image with three half-fuzzy disks of light in neon representing the first, second, and third collisions of electrons with the gas? If I'm understanding that correctly, that's such a ludicrously awesome picture. wow!

    • @jkzero
      @jkzero  24 дні тому

      You are right, those fuzzy discs are the radiation coming from neon de-excitation after the electrons collided with them. I find this image insanely fascinating.

    • @AlphaPhoenixChannel
      @AlphaPhoenixChannel 23 дні тому +1

      @@jkzero AWESOMEE!
      sorry I should have specified first three “energy transmitting” collisions 😁

    • @jkzero
      @jkzero  23 дні тому

      @@AlphaPhoenixChannel no worries, it was clear. Thanks for watching and your comment. I am flattered to have you here, I am a big fan of your channel. You have showed me how little I understand about how electricity works and, weirdly, I love that feeling. Your latest video recording dragonflies was also great, I look forward to what else you do with your new ̶t̶o̶y̶ tool.

    • @AlphaPhoenixChannel
      @AlphaPhoenixChannel 23 дні тому +1

      @@jkzero thanks! I think this is the first videos of yours I’ve seen but it’s awesome - I’ll be checking out the rest! I love the science history stuff - I recently discovered another channel called chemistorian I think that does similar breakdowns of old experiments. The historical bits on cosmos were always my favorite too. They learned so much with so little back in the day

    • @jkzero
      @jkzero  23 дні тому +1

      @@AlphaPhoenixChannel I really appreciate the compliment, specially coming from someone whose work I admire, thanks a lot. I will check the channel that you mention. I love this period in which so much was unveiled with beautifully simple experiments. Most people focus on the theorists, as a theoretical physicist myself I value experimentalist much more as they really managed to find clever ways to probe Nature so I like to share the stories of less-known physicists and the great impact they had on the work of the famous ones.

  • @spencerwenzel7381
    @spencerwenzel7381 26 днів тому +1

    Excellent video! This channel is one of the few rare channels that I asked to be notified when a new video comes out.
    Honest question here, why does only 4.9 eV get absorbed? How about the higher energy levels of mercury like 6.7 eV and 8.8 eV? Why is there only one spectral line emmitted?

    • @jkzero
      @jkzero  26 днів тому

      Thanks, I appreciate that you value the content. You have a great question there; it is tempting to think that at a voltage higher than 4.9 V the electron will reach the next excitation energy; however, since the energy is gradually increased, when the colliding electrons reach 4.9 eV they give their energy off to the Hg atoms, now they are reset to 0 eV, so they start over from zero to 4.9 eV and again they collide inelastically. In other words, the electrons never get more than 4.9 eV of energy because as soon as they reach this value the give it away. I hope that helps.

    • @spencerwenzel7381
      @spencerwenzel7381 26 днів тому

      @@jkzero Thankyou! That makes perfect sense.

    • @janosvarga9997
      @janosvarga9997 25 днів тому

      That is the way how the striations form I presume. Seems electron needs certain distance to accelerate again to the energy level what the gas atom is willing to absorb.

  • @CDXLIV444
    @CDXLIV444 15 днів тому +1

    This is mind blowing. Wish I understood the equations better though.

  • @valentinului
    @valentinului 12 днів тому +2

    Amazing content ❤, just watched all your videos about quantum mechanics xD

    • @jkzero
      @jkzero  11 днів тому

      Awesome, thank you! Several people have recently discovered the channel and written saying that they binge-watch the quantum mechanics playlist as well as the playlist on the physics of nuclear weapons. I really appreciate the positive feedback. More coming soon.

  • @threeMetreJim
    @threeMetreJim 28 днів тому +5

    That's fascinating. When using Neon, why do the areas of inelastic collision form distinct bands though?

    • @GRosa
      @GRosa 28 днів тому +7

      My guess is that, when the accelerating voltage is high enough to permit various inelastic collisions, the electrons after the first inelastic collision have time to accelerate to the next collision, covering a certain distance. This repeats after each inelastic collision. In the meantime, the Ne atoms are excited and falling back to their ground state during those collisions, emitting light in the process, which becomes visible as those stacked bands of light.

    • @threeMetreJim
      @threeMetreJim 28 днів тому +2

      @@GRosa Yes, the collisions cause the light, but why the bands?. The banding would suggest some probability of positions, but why no glowing anywhere else? Do the electrons only 'bounce' in a forward direction? The electron speed only decreases by the energy loss in the collision, they don't need to regain any speed (from what I understand in the video). Maybe the banding gaps are something to do with 'mean free path' in the mercury vapour? I'm guessing the number of bands also is an indicator of applied voltage (number of possible inelastic collisions before the energy is too low to produce an inelastic collision that produces light).
      Ok I get some of it now, any electrons bouncing backward will have to be accelerated in the forward direction again, I guess this effect causes no light emission in the backward direction as they only reach the energy required to reach the 'collector' at the far end pretty rapidly; they already passed the main accelerating grid.

    • @zulumike993
      @zulumike993 28 днів тому +5

      @@GRosa IOW - the glowing bands indicate the location where the electrons - under the influence of an accelerating electric field - have reached the speed (kinetic energy level) necessary to have an inelastic collision with the Ne atom, transferring their energy to the latter. I'd imagine these bands would compress - and more bands appear at the far end - as the accelerating voltage goes higher through successive increments the band gap energy of the gas atom.

    • @GRosa
      @GRosa 27 днів тому

      Yes, I agree with that except the last part. I don't think it has anything to do with "band gap energy"

  • @mrhassell
    @mrhassell 6 днів тому

    The most well video ever made on Frank-Hertz’s work. Excellent!

    • @jkzero
      @jkzero  5 днів тому +1

      thank you, I am glad you liked it

  • @jerryking2418
    @jerryking2418 28 днів тому +2

    Very Interesting and crystal clear.

  • @DocM221
    @DocM221 28 днів тому +2

    Love the videos, keep it coming!!!

  • @user-nz8hp6if2m
    @user-nz8hp6if2m 22 дні тому

    One of my favorite experiments explained in detail on the best UA-cam channel. 🎉

    • @jkzero
      @jkzero  22 дні тому

      Wow, thank you!

  • @nachiketrao5285
    @nachiketrao5285 26 днів тому

    Your ability to condense complex theories in physics into such informative videos is nothing short of amazing!!🤯 This has been my favourite channel since I discovered the nuclear related videos❤

    • @jkzero
      @jkzero  26 днів тому +1

      Thanks, I am glad you like the video and I appreciate the good vibes. I just have a great time making these videos and I am thrilled to have found an audience who are interested in the stories and don't shy away from some math.

  • @jbflores01
    @jbflores01 28 днів тому +2

    Excellent video! Great work! Thanks!

  • @tmo314
    @tmo314 18 днів тому

    This stuff is phenomenal. Particle science is so fascinating and your videos really make me want to learn even more!

    • @jkzero
      @jkzero  17 днів тому

      Awesome, thank you!

  • @AbideByReason
    @AbideByReason 24 дні тому

    Another great video Dr. Diaz! I love the logical breakdown of all the physics and math along with the experimental setup, it was really nice to follow. Super helpful including the film from the Physical Science Committee too.

    • @jkzero
      @jkzero  24 дні тому

      Glad you enjoyed it! Those old physics films are a gem.

  • @kelleysimonds5945
    @kelleysimonds5945 22 дні тому +1

    Truly excellent explanation and presentation.

    • @jkzero
      @jkzero  22 дні тому

      Glad you liked it

  • @sphakamisozondi
    @sphakamisozondi 28 днів тому +1

    Splendid upload as usual Dr. By this time next year. Your channel will be bigger.

    • @jkzero
      @jkzero  27 днів тому

      thanks, great to have loyal viewers returning here

  • @Muonium1
    @Muonium1 28 днів тому +3

    Being mostly self- taught, and in a sort of haphazard scattershot way about these sorts of things, this particular experiment somehow escaped my notice until relatively recently, just a couple years ago. What's so beautiful about it, aside of course from its parsimony in validating the Bohr model, is also the fact that it neatly and completely explains the spontaneous appearance of the regularly spaced bright glowing striations in the so called "positive column" of a DC glow discharge plasma, and how they seem to multiply while filling the same space, as voltage to the discharge tube is increased. Higher kinetic energy of the electrons, greater ability to undergo more inelastic collisions with the atoms of gas along the length of the tube. Simple.

  • @faisalsheikh7846
    @faisalsheikh7846 28 днів тому +2

    Best physics channel❤

  • @mattwillis3219
    @mattwillis3219 28 днів тому +2

    16:48 for one of the coolest physics demonstrations eVaR!!!!!

    • @jkzero
      @jkzero  27 днів тому +1

      totally agree, this is insanely cool to literally see where the neon atoms "decide" to accept the energy from the colliding electrons in perfect agreement with Bohr's model

  • @Phantomphyz
    @Phantomphyz 22 дні тому +1

    James Frank is giving very mindful, very demure - he doesn’t come to work having read all that extra literature but still get it done 👏 As a physics student, your videos always help me gain more insight on topics that deserve so much more appreciation! My favorite part of your work is the historical context you give. It really is unmatched compared to other UA-cam channels - I’m excited to see more.

    • @jkzero
      @jkzero  22 дні тому +1

      I am glad that so many people have really liked the brief segment with Franck describing in such a humble way the remarkable experiment he did. It is great having physics students here, most of the content in the channel are things I was never taught in school but are very interesting, these stories are what made me fall in love with physics as a kid. Now that I have the training I can reproduce the math and understand them better. Since leaving academia the only thing that I really miss is teaching so I created this channel and I am grateful for the great community that I have found here.

  • @davidhand9721
    @davidhand9721 24 дні тому

    That neon tube demonstration is just beautiful

    • @jkzero
      @jkzero  24 дні тому

      I find this image insanely fascinating

  • @pedronobre3898
    @pedronobre3898 26 днів тому +1

    Amazing video quality, as always. Soon, you may become unparalleled in the physics content community.

    • @jkzero
      @jkzero  26 днів тому

      Thanks, I am glad you like the video and I appreciate the good vibes. I just have a great time making these videos and I am thrilled to have found an audience who are interested in the stories and don't shy away from some math.

  • @ProfessorBeautiful
    @ProfessorBeautiful 25 днів тому

    Terrific! Totally clear explanation. Brilliant conclusion too. Delightful

    • @jkzero
      @jkzero  24 дні тому

      I am glad you liked it. The clip with James Franck is just great.

  • @Pepesmall
    @Pepesmall 17 днів тому +1

    Lol he basically said "Yu-Gi-Oh players don't read" before it was even a glimmer in a meme lord's eye

  • @yeetingkelp8624
    @yeetingkelp8624 28 днів тому +2

    Fascinating

  • @jmmahony
    @jmmahony 5 днів тому +1

    I think there's a small error in the bottom line at 4:50. The cos inside the square root should be sine squared.

    • @jkzero
      @jkzero  4 дні тому +1

      Oh rats, you are so right. I checked my notes and I clearly have a sin²θ instead of cosθ. I added an erratum in the video description reporting the typo and acknowledging you for spotting it. Thank you for reporting this, I do my best to avoid these typos but after watching everything many times some minor details slip through. Thanks again.

  • @donk8589
    @donk8589 28 днів тому +1

    This is what science should be - exciting and fascinating, not something that crushes your spirit like it's taught in schools.

    • @genebrown7920
      @genebrown7920 27 днів тому +2

      What? Your spirit was "crushed" in school science classes? Not mine! I could not wait to get to my next physics class. Every day I learned more fascinating things about physics (and the world)!

    • @jkzero
      @jkzero  27 днів тому +2

      I am glad you find the content "exciting and fascinating" that is exactly how I feel when I have the opportunity to talk about these topics, this channel is my way to continuously talk about cool physics

    • @donk8589
      @donk8589 27 днів тому

      @@genebrown7920 You were lucky to have good teachers. For me it was nothing but mathematical formulas to regurgitate

    • @coolcat23
      @coolcat23 27 днів тому

      @@genebrown7920 Same, I loved physics in school and at university (as a minor subject).

  • @dosesandmimoses
    @dosesandmimoses 14 днів тому

    That is what I saw in my idea of propulsion- brilliant

  • @fareedjavadi2122
    @fareedjavadi2122 22 дні тому +1

    Very well explained . Thank

    • @jkzero
      @jkzero  22 дні тому

      Glad it was helpful!

  • @mariacordero6194
    @mariacordero6194 28 днів тому +1

    Outstanding content as usual ❤❤❤
    Keep them coming ❤❤❤

  • @ck3908
    @ck3908 24 дні тому

    Wow, this is beautifully done and so easy to understand. Thanks!

    • @jkzero
      @jkzero  24 дні тому

      Glad it was helpful!

  • @N_0706
    @N_0706 24 дні тому +1

    Great video! Could you make a video on the Davison Germer experiment which verified Debroglie's hypothesis?

    • @jkzero
      @jkzero  24 дні тому +1

      Yes, the Davisson-Germer experiment is definitely coming, I have to cover de Broglie first but yes, this is on the list

  • @GeoffryGifari
    @GeoffryGifari 27 днів тому +1

    Ahhh I redid this in the modern physics lab course!

  • @DavidMFChapman
    @DavidMFChapman 28 днів тому +1

    Thank you!

  • @АлексейИлларионов-ш5о

    Great video! My lovely how and why physics history telling with results their meanings and consequences. Thank you a lot ❤

    • @jkzero
      @jkzero  5 днів тому

      Glad you enjoyed it!

  • @randall.chamberlain
    @randall.chamberlain 28 днів тому +1

    Fantastic presentation

  • @fredericharmand
    @fredericharmand 28 днів тому +1

    Very interesting. Thank very much , I didn't know this very astute experiment.

    • @jkzero
      @jkzero  27 днів тому +1

      thanks, my motivation is precisely to make these groundbreaking experiments that are only known to physicist a bit more mainstream; they are fascinating and not necessarily hard to understand, and their consequences were historical. I am glad that you now know about Franck-Hertz, I hope you think about it every time to encounter a fluorescent lamp

  • @giorgiobarchiesi5003
    @giorgiobarchiesi5003 26 днів тому

    Great content, explained wonderfully well. Thanks!

    • @jkzero
      @jkzero  26 днів тому

      thanks, I am glad you like the content.

  • @GRosa
    @GRosa 27 днів тому +3

    If Franck's collaborator was named Stein instead of Hertz, the experiment would be known as Franck an' Stein experiment. 🧟🙃

    • @jkzero
      @jkzero  27 днів тому +2

      love it; I have to be honest, only after the recording of the story I realized that many times I said Franck-and-Hertz way too fast

    • @douglasstrother6584
      @douglasstrother6584 26 днів тому +1

      Franck-und-Stein Experiment!

    • @GRosa
      @GRosa 25 днів тому +1

      @@douglasstrother6584 Ja gut, so wäre es aber auf Deutsch.

  • @gloriosatierra
    @gloriosatierra 21 день тому

    This what happens when I think about electrical circuits in my car: I want to know how it is happening. I am still learning how to read circuit diagrams.

  • @UncoveredTruths
    @UncoveredTruths 28 днів тому +2

    oh yes, the literature seems to slip my grasp too ...

  • @darrennew8211
    @darrennew8211 23 дні тому

    What a very cool experiment and explanation.

    • @jkzero
      @jkzero  23 дні тому

      Thanks, I am glad you liked it. This is indeed a beautiful experiment.

  • @GeoffryGifari
    @GeoffryGifari 27 днів тому

    so cool to see what retro automatic plotting device is like

    • @jkzero
      @jkzero  27 днів тому

      I loved it when he said "this this I would like to use and automatic recording device" and showed such an old-fashion plotting device

  • @Moletrouser
    @Moletrouser 13 днів тому

    Rutherford inferred the structure of atoms from the scattering of alpha particles, originally from metal surfaces. The Geiger and Marsden experiment was designed to confirm (or refute) his prediction, which had already been published before that experiment was run.

    • @jkzero
      @jkzero  12 днів тому

      I was not aware of the early publication that you mention, could you share the reference? I would love to check it out

  • @GRosa
    @GRosa 28 днів тому +1

    I don't remember repeating this experiment during my undergrad studies. 😅

    • @jkzero
      @jkzero  27 днів тому

      oops

    • @GRosa
      @GRosa 27 днів тому

      ​@@jkzeroI did them, the studies, a long time ago (1987-1991). 😔

    • @jkzero
      @jkzero  27 днів тому +1

      @@GRosa ok, that was a bit earlier than me, I was starting elementary school in those years

  • @Schraiber
    @Schraiber 18 днів тому

    I think I'm still confused by whats wrong with the naive calculation that results in elastic scattering. It seems like the key there was just that the mercury atoms are way heavier than electrons, not necessarily any assumption about continuous or discrete energy levels.
    Is the solutuon that the inelastic scattering arises not from bumping into the "atom" in bulk but specifically from colliding with one of the electrons around the atom, which is small enough that there's the opportunity for inelastic scattering?

  • @matthewhoag2609
    @matthewhoag2609 26 днів тому

    Excellent presentation!

    • @jkzero
      @jkzero  26 днів тому +1

      Thank you kindly!

  • @luudest
    @luudest 7 днів тому

    Thanks for thins interesting video. I love stories from the dawn of new theories.

    • @jkzero
      @jkzero  7 днів тому

      Glad you enjoyed it! In case you haven't, make sure to check the currently running series on quantum physics ua-cam.com/play/PL_UV-wQj1lvVxch-RPQIUOHX88eeNGzVH.html

  • @SimulatedEarthboundMisfit
    @SimulatedEarthboundMisfit 24 дні тому

    I ♥ the scientific method.
    And, "there's no data like real data".

    • @jkzero
      @jkzero  23 дні тому

      plus this can be reproduced even by undergraduate students, it is a beautiful experiment.

  • @Lolwutdesu9000
    @Lolwutdesu9000 19 днів тому

    Nice video but the circuit diagram used around halfway through the video to showcase the experiment is slightly incorrect (it's the oversimplified version often shown on the Internet but is flawed).

    • @jkzero
      @jkzero  19 днів тому

      I always welcome corrections, thanks

  • @RandomerFellow
    @RandomerFellow 8 днів тому

    Very good review of the experiment.
    (Interesting that the Americans used “centigrade” at that time.)

    • @jkzero
      @jkzero  8 днів тому +1

      yeah, in physics classrooms in the US you don't find the commonly used units. I was very surprised when teaching in the US that problems sets never use miles, pounds, or Fahrenheit

  • @dleddy14
    @dleddy14 22 дні тому

    Great explanation!!

    • @jkzero
      @jkzero  22 дні тому

      Glad it was helpful!

  • @mikehibbett3301
    @mikehibbett3301 27 днів тому

    This must have been such an exciting time in Physics

    • @jkzero
      @jkzero  27 днів тому

      right? I like to say that most people get excited about the late 20s with Heisenberg, Schrödinger, and Dirac but I personally find the early quantum physics quite fascinating, the close interaction between experiments and theory, that must have been a great time to be a physicist

  • @tyeadel
    @tyeadel 28 днів тому +1

    Shows the existence of stationary states for Hg

  • @no-one_no1406
    @no-one_no1406 24 дні тому

    Confusing. Why does the peak correspond to the excitation energy step, and not the valley?
    Assuming the test electrons have a normal distribution in energy, would not the excitation energy point show a reduction in ½ of the target current?

  • @pieterduplessis6632
    @pieterduplessis6632 14 днів тому

    Great video, thanks for sharing

    • @jkzero
      @jkzero  13 днів тому

      Thanks, I am glad you liked the video. In case you haven't, make sure to check the currently running series on quantum physics ua-cam.com/play/PL_UV-wQj1lvVxch-RPQIUOHX88eeNGzVH.html

  • @gene4094
    @gene4094 14 днів тому

    The mercury voltage discharge appears to reach the maximum of the ‘ ultraviolet catastrophe’.

  • @carlbrenninkmeijer8925
    @carlbrenninkmeijer8925 24 дні тому

    Thank you so much !!

  • @luudest
    @luudest 7 днів тому +1

    16:55 How come there is pattern of the radiation? Why does the light not radiate away in all directions?

    • @jkzero
      @jkzero  7 днів тому

      light is indeed radiated in all direction, the pattern arises because the light produced at those particular points

    • @lepidoptera9337
      @lepidoptera9337 6 днів тому

      @@jkzero Light from a single source does not and can not radiate in all directions. The lowest possible mode of an electromagnetic field is a dipole. Uniform radiation from a classical light source is the incoherent superposition of many such dipoles.

  • @vinniepeterss
    @vinniepeterss 28 днів тому

    top of the line video!

  • @philoso377
    @philoso377 25 днів тому

    One thing that fascinating me about the negative slope corresponding to non elastic collisions and we took that electrons speed were transferred into EB radiation by the mercury atom, where did the electrons end up after the collision? Disappeared from the universe?

    • @janosvarga9997
      @janosvarga9997 24 дні тому

      I presume in those regions, they have insuffient energy to make it to the anode and they just flow in the acceleration loop.

  • @GeoffryGifari
    @GeoffryGifari 27 днів тому

    I noticed that the energy for mercury ionization is 10.4 eV, the same for n=1 case of the Bohr model. I imagine if the voltage goes further we'll see a sharp spike

    • @GeoffryGifari
      @GeoffryGifari 27 днів тому

      Also, mercury atom being as heavy as it is it's pretty cool that its valence shell can be so closely described by the Bohr model and not obfuscated by having so many interacting electrons inside

    • @jkzero
      @jkzero  27 днів тому +2

      well, in the film they push it up to 30 V; it is tempting to think that at 10.4 volts the electron will reach the ionization energy; however, since the energy is gradually increased, when the colliding electrons reach 4.9 eV they give their energy off to the Hg atoms, now they are reset to 0 eV, so they start over from zero to 4.9 eV and again they collide inelastically. In other words, the electrons never get more than 4.9 eV of energy because as soon as they reach this value the give it away

    • @GeoffryGifari
      @GeoffryGifari 27 днів тому

      @@jkzero Assuming every electron can't go far enough without hitting a Hg atom right?

    • @jkzero
      @jkzero  27 днів тому +2

      @@GeoffryGifari yeah, the trick here is to make the mercury density high enough so that the mean-free-path is shorter than the length of the tube

  • @BrentLeVasseur
    @BrentLeVasseur 7 днів тому

    It doesn’t explain ‘why’ this occurs, only that it does occur. The “why” has to do with wave mechanics between the longitudinal resonant frequency of the nucleus of the mercury atom, which creates the spectral lines or orbitals of the atom; and which also then drives the transverse oscillations of the electron orbitals. If you have ever seen or played with cymatics, where a longitudinal wave (sound) is focused on some kind of medium like sand, you will see patterns emerge, which are unique to the specific resonant frequency of the soundwave. All atomic nucleus are essentially oscillating longitudinal voltage potentials/standing waves in the Aether/ZPE field. And as such, the resonant frequency of the nucleus dictates and manifests where the transverse electron orbitals occur due to wave multiplication/cancellation effects. Its that which makes the spectral lines for each atom appear. It’s all just a matter of the longitudinal frequency of the atomic nucleus. So atomic nuclei are just standing longitudinal waves in the Aether/ZPE field at a specific resonant frequency.

    • @lepidoptera9337
      @lepidoptera9337 6 днів тому

      Yes, that was nonsense. ;-)

    • @BrentLeVasseur
      @BrentLeVasseur 6 днів тому

      @@lepidoptera9337 Have you seen a demo of cymatics? You can see some videos of it here on youtube. It becomes much clearer when you can visualize how longitudinal/scalar wave impulses drive transverse oscillations, which is the true relationship between the nucleus and the electron orbitals of the atom. The nucleus is a scalar impulse oscillation which drives the transverse electromagnetic waves around the atom (electrons), which gives it volume. Both are Aether/ZPE field phenomena.

  • @hanyahamba-AlKhaliq
    @hanyahamba-AlKhaliq 17 днів тому

    Thanks Dr.

  • @nikospitr
    @nikospitr 6 днів тому

    i love these old experiments

    • @jkzero
      @jkzero  5 днів тому +1

      same, I find these simple table-top experiments fascinating

  • @jeanalpha2401
    @jeanalpha2401 18 днів тому

    Can someone explain me, on the graph at 16:14, why the peak of inelasticity (and so emission) is not refered as 5.5eV instead of 4.9. Woudln't it make more sense that the energy transition is where the curve is locally minimal ?

  • @SciD1
    @SciD1 27 днів тому

    An anode is not a negative collector, it's positive.

    • @leonhardtkristensen4093
      @leonhardtkristensen4093 26 днів тому

      In this tube the anode is really the accelerating grid I would have thought. The collector is negative compared to the accelerating grid but positive compared to the controlling grid.

  • @ai-pictures8833
    @ai-pictures8833 12 днів тому

    It's not about energy of 4.9eV but frequency in which they are hitting Hg atom.

    • @jkzero
      @jkzero  12 днів тому

      I am not sure if that agree or even understand what you mean by frequency here

    • @ai-pictures8833
      @ai-pictures8833 12 днів тому

      @@jkzero 4.9eV gives electron certain speed which means he will hit Hg atom only at certain time. I mean time when electron is hitting Hg atom is crucial. After it hits, electron again needs to pass some distance to gain that speed(2×4.9) which will when it hits be at certain time. Is it really about energy or timing when it hits the atom?

  • @MrRObot-bin
    @MrRObot-bin 27 днів тому

    Grcias Dr. por estos increíbles videos.

    • @jkzero
      @jkzero  27 днів тому

      gracias por la visita y el comentario

  • @youth1482
    @youth1482 27 днів тому

    Mesmerizing!