This channel has to be hands down my most favourite channel. The greatest stories almost no one knows.

One of the biggest hurdles that made my mind blocks physics in the colledge was why on earth did these famous ones think about what they were working on. If I knew the historical background, many seemingly non logical aspects of physics would have come clear and smooth. I do not claim I understood everything thing you mentioned, but I really wish I had a teacher like you. Thank you for the video and the explanation included therein.

Our freshman chemistry professor did this derivation for us many years ago. It really struck home to the class the amazing feat that a theoretician could derive the experimentally determined Rydberg constant. A well-deserved Nobel.

I’m so glad you did the math with historical commentary. Great job! My teacher in Modern Physics did all the same math but without the historical motivation. Showing how the sausage was actually made helps young scientists understand how to approach the scientific process better. Every undergrad physics/engineering major should watch your series. Thanks.

Another great video! Hilarious how Fowler tried to be skeptical because of a small decimal difference, but it did end up to Bohr correcting his math and getting it even better!

I love how down to earth the explanations are for quantum physics. I thought that they were all these crazy ideas pulled out of nowhere, but watching this channel showed me just how logical and relatively easy the explanations are to follow

Wowza! That was a lot of work! Great video! I'm going to have to watch that a few times.

Thank you for all the time you put into this explanation, truly clear and effective. Of all Copenaghen School bunch of Scientists, in my opinion, Bohr was the most profound in the inception of new scientific objects. His ability to match elements from different sector of Science, was unmatched as it was unique...

I wish I had professors with your clarity of presentation during my undergraduate years. I might have gotten my money's worth from all that tuition.

Thank you so much for this explanation of the math behind the Bohr's model of the atom. I saw the main concepts in high school, but I never thought that I would understand their logic and the story of how the physicists developed these mathematical formulas. 😊

Wow, Kathy. That was a fantastic video. It brought back so many memories of my undergrad physics class in spectroscopy. That's where I first encountered the Bohr theory of the atom formally. I'd read about it in high school, but didn't understand the math. My spec instructor was a very practical guy who worked in one of the physics labs for Dow Chemical in Midland, MI. I learned so much from him.

Great work! I've always appreciated my physics teachers who take the time to explain the historical concepts of the things we learn in our classes. Keep up the great content and thanks for what you do.

Thanks Kathy! (Btw minor typo at 8:41, a missing "2" square on the v. The math does work out implying the 2 is still there, it just didn't show on the display.)

This is a beautiful exposition. Wonderful!

Great presentation! Made me nostalgic of my college physics days .Keep up the good work Ms Kathy. .Looking forward to more. .Thanks & keep safe.

Wow! Nice walk through the math of Bore's model! Unfortunately the derivations went too fast for an old guy who's math is a bit weak, but I was able to follow the main line of logic. Thanks! Bore was truly amazing. I also appreciate the back story of his relationship with his wife, who was obviously a full partner. We often think of creative scientists as existing in some sort of vacuum and splendid isolation! I would submit that is seldom, if ever true!

Really awesome! You are doing a great job! Physics community is lucky to have you on board! :)

Found this channel few days ago, and can’t stop watching so many great content. Awesome job, Kathy!

Probably the best video series on quantum mechanics that I have ever seen

Your channel is a treasure trove! So much physics and history.

she is unmatched, For every one of us that teach STEM, take her as your gold standard.

Truly outstanding video. I’m so impressed by your work, and thank you for sharing with us.👏

Back in 1965 or 66, at the beginning of a chemistry course, we were introduced to the Bohr model. I didn't understand why at the time since the mini-solar system model of atoms was out of fashion. Only now with your videos do I realize what an amazing achievement it was.

Just to mention , I live in Denmark and his son Aage Bohr did also achieved a Nobel price in physics. And frankly thycho Brahe were also danish. But as usual a very enlightening story about how physic evolved especially around the beginning of the the last century. And happy new year 😊🎸. I just wish I was so much better doing math. But I think I understand some of the bigger picture but quantum physics is so hard to get and Richard Feynmans quote does tell that everyone gets a bit dizzy trying to understand quantum physics. 🇩🇰🎸

This channel gives us a root insight in the legislative process in modern physics.

Finally got an explanation! Thank you very very much ma'am!

Mam you are great .you do lots of work and explore , explain us the reality of historical inventions . Thanks mam 🙏🌿🌎

Thanks I am just an amateur with a PHD in Political Science -- these help me get a notion of the basics and inspiration from the ups and downs of the efforts by great names in Physics

While I'm not the greatest with math, I might be able to reproduce your most of your frames, you didn't skip something. Thanks for making this more accessible.

Wow! I am blown over. Thank for very much for your commendable efforts. I learned a lot.

Kathy’s storytelling is next level.

Excellent, I will be rewatching this too

Super! Thank you for the nice explanation. This was one of my favorites :)

It is always welcome, having a complex topic able to be made understandable by someone with the right knowledge - thank you. It has always puzzled why the electron remains where it is and fails to lose energy and does not fall into the nucleus, because of the proton-electron attraction. The satellites we send to space are powered to remain in orbit; when they are old and lose the energy and the means to correct/re-establish a proper orbit, they fall to Earth and the atmosphere has the final say. Electrons do not have on-board systems to correct/maintain an orbit yet there they are.

Brilliant channel, thanks Kathy

yay - thank-you so much for jamming through these theories and equations.

Very good. Please continue to load similar videos frequently. Thanks and Regards 😊🙏🙏🙏🙏🙏🙏

Love this deep dive!

Enjoyed your excitement. Trying to follow.

Thank you for this wonderful explanation!

Ok, that was convincing! So you are really good at physics, not just at storytelling! Good job!

I had most of this in high school (not Pickering though, what a jerk), and admittedly was taught well. But I do wish these videos had been around! Of course, this was 30 years bY (before KZfaq 😁). Thank you!

As always, excellent!

Even after 3.5k views there is no dislike Right viewer meets right information

First day in freshman chemistry here's the derivation of the equation for the Bohr model of the hydrogen atom. Memorize it. Test to reproduce it next week. It was a tough school and only got harder from there. 4 of the most grueling years of mental work in my life and worth every second of it. This quantum jump comes up over and over again especially in electrical engineering. It's one piece of evidence for a possible additional dimension we can't sense.

Your explanation gives me the odd feeling that I might that I might understand equations. Thank you.

Im loving these videos..

I think there is a mistake in 8:41 to 9:16. The equation should have the term mv^2 instead of mv.

I love these videos! History provides so much interesting context. One point on this one however.... I would use the word "Revolving" rather than "Rotating" in assumption 5 b). The acceleration that was expected to produce classical radiation is centripetal -- like a cyclotron. Rotation implies spin which wasn't a consideration in Bohr's model.

Thanks Kathy for another excellent video. I love your videos on science and the founders of modern physics. I think that Fowler was quite right to question the slight difference between observation and theoretical prediction. That is one way in which theories are tested, improved or changed. I wonder what nuclear mass Bohr used when calculating the efffective mass for the electron in Helium.

Great video! Kathy is what happens when Miss Frizzle meets Einstein! I have intended to do something like this for a while but looks like Kathy is more energetic then me. This issue has bothered me for a while since I read through Bohr's original paper. All of the intro textbooks get this wrong, claiming that Bohr quantized the angular momentum which lead to his result. I think it is enlightening to read the paper and realize that Bohr basically pulled the "average angular frequency" out of thin air and then concluded that the angular momentum is quantized.

Can you make a video on Bohr-Sommerfeld model pls? I'd like to know more about the so called "old quantum machanics" and what they came up with those things. By the way I just descovered this channel and it is INCREDIBLE. The only thing I'd like more is the possibility of looking at some sources, maybe putting some more links in the description?

You GO girl. Thanks for the smiles.

Show! Thanks for the explanation

Beautiful step by step deduction of the Bohr model of the atom. All credit to Kathy.

This is awesome!

Absolutely brilliant presentation! Thanks for some great videos!

1/lambda is called wavenumber, designated usually with nu bar or nu tilde. The effective mass is called the reduced mass. Discrete energy levels were supposed around 50 years earlier by some spectroscopists and they were called terms.

Brought back memories of going through these derivations in Physics class. The professor began with "we are going through Bohr theory of the Hydrogen atom. But don't worry it's really not a major bore." 😂

excellent video

Best episode yet… Nice colors… Lighting 🚀🚀🚀, Make -up 👀 Subject matter interesting..🐦🐦🐦

This is great 👍

"Discrete" is a magic word. Old-timers knew about all kinds of phase changes and evaporation, sublimation, condensation is pretty magical, unless you know what holography is in relative-timing ratio-rates density-intensity nodes separated by dimensionality spaces as in 0-1-2-ness GD&P parallel coexistence. Which is the job of the next generation to explain, "teaching by undoing" phase-locked e-Pi-i sync-duration resonances. So I'll check in again later.

Good stuff 👍👍

Note that with quantum mechanics, the values are all discrete so they all belong to the set of Rational numbers (can be equated to the discrete sequence 0, 1, 2, 3, ...) as far as going from one to the next one. This means that the scenarios that create these results are also discrete (completely separate from their nearest neighbors). This result implies that if there is a multiverse interpretation of these rules (Everett "Many Worlds" interpretation), then each universe of this multiverse is completely separate from all others, too. They are thus not points on a line with no visible boundaries between such points, as in the infinitely larger set of Real numbers. This not only changes the results, but the concepts on which these results are based and is one of the basic differences between quantum physics and all forms of non-quantum physics (Classical, all forms of Relativity, etc.).

Awesome, Thanks

Great video, thanks :)

love it!

Thanks for the video. It was really insightful but I guess I will need to study a bit to digest everything here. What I found interesting is the Rydberg mass for a system formula is a harmonic mean. Well now I am curious as to what practical uses are for geometric mean

Oh my word. Physics is beautiful

Very decent explanation. None know everything, but it's good to be correct in the little one knows. 😊

Please enlighten me. One can consider 'electron motion in an atom' from two perspectives, classical and quantum. The quantum picture relies on a statistical formula, the Schrödinger equation. It comes up with maximum 'entropy' solutions for the statistical shapes of the orbitals. The classical approach needs to take the quantum idea of somehow canceling the radiation from the electrons in their orbits. Then it is left with the task of solving ordinary differential equations including the effects of electron spin: a hopeless task, considering that the solutions are most likely deterministically chaotic. Is there any mathematical way of checking whether those chaotic solutions might have statistical properties that could be compared with the Schrödinger maximum 'entropy' solutions? Please enlighten me.

As always, I like it

Excellent!

Fantastic

Great videos. Please make a video on Lise Meitner.

How is the work needed to set the electron free from the atom equal to the difference between it's potential and kinetic energy? Can anyone give me an explanation for that?

thank you! My head is spinning!

Wish to meet with you near future .mam one question ,are ASSUMPTION, CONVENTION and IDeal nature oppose the reality 🤔🤔🧐🌿

Hello mam, I m not able to understand why he assume electron move around the nucleus

Do you offer any certificate of attendance for all these your lectures?

Thanx!🙂👍

So basically, Bohr was the quantum Maxwell. My respect for Bhor has risen exponentially after listening to these two videos.

Great stuff. Thanks for the math. I suppose you folded part 5 into part 4 there.

Thank you...I don't know math very well...but the way they figured this out is exciting. Isn't this what gave Einstein the idea how to create a laser light? Do you have a video on lasers??

[Ze] is also the chemical symbol for the element zenc.

I would love to watch this video. Could you re-shoot this and keep your hands on your table?

Great video Kathy! Not a Bohring moment. I’m sorry… low hanging nuclei.

What really amazes me is the elaborated model, sometimes called "the old quantum theory", that Bohr and Sommerfeld developed, in which they started introducing elliptical orbits with the same principal quantum number and different angular momenta. What specifically fascinates me about it is that they would have been able to take it much further than they did had all of their angular momenta not been off by one unit of hbar! It was a mistake that was easy to make because of the energy degeneracy of different angular momentum states for hydrogen-like atoms, and maybe the idea of an electron with ZERO orbital angular momentum and an orbit that bobs in and out, right through the nucleus, was just too absurd for Bohr and Sommerfeld to contemplate. Once wave theory arrived it wasn't quite so absurd. It was maybe the most significant off-by-one error in physics, one that contributed to further progress, since it led physicists to abandon "the old quantum theory" with quantized orbits earlier than they might have otherwise.

I don’t view Planck’s E = hν as really quantized, as E and ν are continuous variables, unrestricted until Bohr introduced quantum jumps that match the Balmer (and Lyman?) series. It’s been a long time since graduate schools

Bravo!

Two physicists meet in the hallway. Quantum physicist: What’s up with your area? Classical physicist: Negative Del dot g, like always. What’s new with you? Quantum physicist: E over h, as usual.

So a zero is a naught but nothing is a different naught? BTW I am more familiar with "ought" for zero as in the rifle cartridge 30-06 which is usually pronounced "thirty ought six"

But rotating electrons radiate energy between retrograde motion connected with gravity waves.

It seems the idea it is in orbit is in the calculation, and yet is this the quantum interpretation of the position of an electron?

Actually did bohr imagine his model of atom just as two dimensional?According to his model does all the orbits exist in one plane (Its always shown in a plane)?

Check out, what Walter Russell, said about Bohr's 'quantum-jump'.

Thnx granny for the video..

"An infinitely big Nucleus", that would be a ONE-INFINITY Singularity Universe of Logarithmic Time, in which deterministic pure-math relative-timing ratio-rate quantization is the fundamental self-defining Holographic Principle Reciproction-recirculation manifestation of all physical phenomena, such as been illuminated, made real-time Actuality.., so well in this video.

10:39 in my NY accent, 'not' and 'naught' are not pronounced the same. nought = 'nawt.' i knew saying cawfee, dawter, and dawg would eventually come in handy.