Photoelectric Effect: History of Einstein's Revolutionary View of Light 

No, You Did Not Mess up. You are a Fantastic Teacher. Its Hard to Imagine that how much time and effort you had given for all your research and telling us all the story.

Excellent videos Kathy. As a physics teacher with a deep interest in the history and philosophy of science, they really help to bring the subject alive for my students. It's great to see references to the original papers too, something that most other channels neglect.

I have always found it easier to absorb a physics theory once you know a bit about why/how/when it came about and what was the previously leading theory. I cannot but think you are helping a lot of physics students with your storytelling.

please stop making excuses about "messing up. ". you're the most fascinating science reporter ever and so much fun to listen to. The human connections behind all this science work is truly what life is all about . please continue "messing up " or not And i vote not messing up !!! As you breathe life into the scientific world .. we all appreciate you for that ❤

I just discovered this series and I love it! The integration of the personal life stories, the social and economic environment of the times, and the contemporary research and papers put out by others, all add to the value of what you’re presenting.

The man is the definition of thinking outside the box. That miraculous year when his mind was razor sharp. He looked at things, thought deeply about them, saw some logical inconsistencies, and then, saw what had to be true, no matter how odd it seemed

RU-vid must be broken, this channel should have 100K subs.

This entire video series is like attending a friendly delightful informative course on the history of electricity and physics. Absolutely awesome. I think kathy had an annus mirabulus when she up loaded these videos and finally this corona lockdown will make her famous. As more and more people watch and share the videos.

You do such great work, Kathy. I always leave a little more educated.

The high quality of your videos shows how much work goes into them. Thanks so much for creating them!

Trust me, this is the only channel that I subscribe in my entire life. Always give me new knowledge. Can't wait for the next videos.

I love your presentations Kathy!!!! They are an enjoyable and informative journey into science and history. Robert Coates

Your channel deserve much better recognition like the other popular science channels. I think will happen in due time.

Wow, a lot of information here I never knew. Excellent. Subscribed!

A big thumbs up! This is the best explanation of the photo-electric effect that I found on RU-vid. A thrilling and entertaining story especially with the historic background. Please continue this series.

Outstanding video Kathy. You made it interesting, easy to understand and your narration is superb. Well done!

8:03 The explanation I remember reading is that “quantum” is the Latin answer to the question “how much?” -- it just means “so much”. There is no implication of “indivisibility” about it -- that’s what “atom” means -- “not cuttable” in Greek. Now there’s a lovely word, “atom”: it seems to have a curse such that any concept it is applied to inevitably turns out, sooner or later, to be indeed cuttable into smaller parts.

This is the best channel and most underrated....Hated youtube algorithm...For not showing until now...

Thanks! We need more videos like this, to put real life into the equations and learn about the many roundabouts science developement requires. Also wonderful the way underconsidertion of Mileva is shown. I'm using all of this for my classes, for sure! ^_^

Its an excellent video. It's pleasure to see references of the original papers. While watching this video I was feeling like I am in that era of Albert and Plank.

Under quarantine days, my professor (about structure of matter) often shared your channel. And I appreciate.

Thank you, Kathy! thank you, Kathy! thank you, Kathy! You’re a great teacher and a better story teller

Opened my eyes.Right from the calculation of speed of light (which required very sophisticated experiments ) ,to the mathematical equations leading to photoelectric effect, light as quanta leading to space time concept makes one wonder the development of physics almost a spiritual experience. I may be wrong in above sequence of events, your videos are eye and soul openers. Lots happenings at a very fast pace these days when observations and experiments are being carried over on grand scale , great to be alive and watching as it happens.

I wish the video titles were numbers not on the thumbnails but the literal titles themselves just so one doesn't have to fish for the next videos... I'm addicted to your content... Very outstanding, Thanks a lot.

Thanks Kathy. I love your videos about science history. When I was a physics undergraduate many years ago one of the things that I found frustrating was that very little information was given about the historical context in which discoveries were made and so it was difficult to imagine what scientists of the time were thinking and trying to do. We would be presented with something like Schrodinger's Equation without having any idea of where it came from. On a small matter, I don't think you pronounced Einstein's daughter Lieserl's name correctly - I think it's more like "lee-zel" - if you have seen the film "The Sound of Music" there is a character with that name.

You clearly explain the concrete contribution of Einstein. Very clear.

Hey Kathy, it’s amazing watching you talking about Physics’ history! Like a thriller

Your enthusiasm is contagious. Almost makes me want to become a physicist. Your pronunciation is just fine. Keep it up.

Your lectures are so illuminating that make me go back in time when I was a young man attending school…Thanks…

You are giving us an ALL-ROUND picture of not only physics but about SCIENCE the great. Thanks and respect. From India.

I just love the way you put what, for others, it could be just a narrative of technical stuff in a way that we can perceive the human drama behind. Thank you for your passion and accuracy in the exposition of these interesting chapters of the human development. I would like to suggest a video on the history of the e number. Thanks again!

Love this channel very much. Thank u for this Kathy. U shall grow to 10 million subs.

This video popped up and it was great. A well edited presentation that had the perfect mix of history & theory for the masses.

One of the best description of Photoelectric effect

Your presentation is, by far, the best on the web! A thousand thanks!

It’s worth mentioning as a bit of background that all women weren’t granted the full right to vote in Switzerland until 1990. Most won the right in a 1971 referendum, although 35% of men voted against it and not all cantons granted full rights. My sister married a Swiss. A lovely man the family adored but his views on gender roles were very Swiss. The early 20th century was firmly embedded in those attitudes and one has to wonder how many more scientific advances humanity could have made if we hadn’t excluded half the population from contributing, and failed to acknowledge them when they did. What if we valued every citizen regardless of gender, race, or ethnicity and enabled them instead of stifling them? It’s one thing to acknowledge the shortcomings of past centuries; another thing to address our own. Excellent presentation. I got more than I bargained for when I searched this topic.

You are fantastic !! I need to hear each video an infinite number of times to get it, and I will :)? So great to hear about the stories and the development of science and it’s explorations. !! The truth emerges !! Such great people behind it all. Thank you !!

Kathy, there's a great hero in this story, an Indian, which is why I'm proding this. Satyendranath Bose, a fellow country man, who we may attribute to first understanding the statistics of photons. Without the statistics, photons are not, photons, just mystic energy packets.

You are extremely eloquent Kathy and very well informed. Your memory and vast knowledge of Science and it's history is astounding. Just in this very short video I learned a lot from you. Thank you.

brilliant.love the background behind the equations.Mileva so under appreciated. keep videos coming. thanks john

Great video Kathy. Can't wait for the next one.

I'm glad my physics education didn't let me down - I did already know the significance of Einstein's description of the photovoltaic effect. You video provides some excellent historical context, though, and I don't think I quite understood how Planck fit into the story before. Excelent video as always!

What a great lecturer! Your exuberance is deeply felt.

Another excellent video - especially the interconnections between all of the people and their theories, ideas and discoveries. I tended to learn about each principle in isolation, as needed to explain the subject at hand. As for your presentation, your pronunciation of some names is acceptable to me because you do much better than I could attempt. A rule I was taught was if you stumble, just power on and most people won't even notice.

wow so - glad to have come across this Video. loved it As a Physics teacher I have been looking for interesting ways to teach to give my students a a real vibe of story behind the discoveries and inventions!

Another great presentation. Thanks.

Another totally fascinating and informative video. Having learned all this in a classroom, how wonderful it is to see it come to life with photos, potted biographies, original papers and documents, and your own special way of narration -WOW! These videos should be available to schools. I think that this kind of approach to science might encourage all those students who reject it as 'too difficult' "just learning formula" "dry". It might make them realise that Science is the longest and most gripping Sherlock Holmes story there is!!! I jest. But there is truth in it. Thank you.

Nice view on Einstein's views. Also what are your thoughts on this guy's view on how Einstein viewed QM: Einstein didn't dislike Quantum Mechanics. After all he was one of its founders. What Einstein did dislike was the approach the development of Quantum Mechanics was taking. He was a big proponent for the idea that physical theories shouldn't just work. They should also provide a linear progression to the previous interpretive/philosophical assumptions from which they are derived from. For him, this was very important becuase he believed this is what allows future physicists to develop new insight. Remember how Einstein reached the conclusion of The Theroy of Relativity? He didn't abandon the old interpretation. He simply refarmed it a way that provided a new insight into the works of space and time. None of his postulates actually proposed anything new. Quantum Mechanics was developed in a highly competitive environment. Where you had the old school, established physicists vs the newly emerging hot guns of the physics world. One side was fighting to preserve their status and the other trying to prove their worth in the new age of physics. This left no time for anybody to stop and interpret the meaning of what they were doing. It was all just fancy maths to prove a point. And now, here we are in the 21st century with a huge and complex theory with no grounded interpretation. Making it very difficult to develop insight. This is what Einstein was concerned about and I for one agree with him.

THESE LECTURES ARE AMAZING !!!

Great video, as usual. Thanks dearly. Please continue improving sound quality..

I love this ladies passion and knowledge about science and physics. More importantly her whole way of her presenting scientific facts. She's a delight to watch even if you don't fully understand all the technical aspects of her presentations. .

An outstanding history of Einstein's discoveries. Thank you, Kathy!

Terrific stuff. Should be viewed in every High School physics class. I always thought that Einstein's Nobel prize for the photoelectric effect should have been for relativity but I now believe the opposite as quantum theory has a far greater effect on scientific thought and technology than relativity. Put it another way quantum theory causes us to rethink the nature of reality itself.

Thanks Kathy. Another excellent video. Have posted a link to this video on my FB page to explain the complexity of early research in physics.

Great !! You could mention that the term 'photon' for an energy packet of light was coined by the famous chemist Gilbert Lewis from UC Berkeley in 1925 (I think)

I appreciate how thorough you are in covering the Einstein's photoelectric effect, including his female counterpart(s).

So there is a basis for "Quantum Physics" other then the dual slit experiment. IDNK!!! Thanks!! IMHO

Watching your videos is like... falling in love !!!!

Great work! I'm gradually getting through the backlog.

Been binging all your videos all week since discovering you. Love all of them!

In the name of Mileva I didn't notice a wrong pronunciation, but the name of her daughter Lieserl didn't even come close. But I always love your presentations

I just discovered you a few days ago and your articles are fantastic. Keep up the good work.

Needs/deserves many more views, likes and subscribes. Kathy creates an excellent presentation.

Just discovered your channel! I haven't been more excited at the prospect of finishing all videos of a channel. You combine two of my favourite interests: Science + history. Just a personal request, though... If possible, could you explain conceptually or simplistically some more details? For example, in this video, could you explain how Einstein put together the relativity principle and Maxwell's equations together to show that mass and energy are not independent. I don't have a physics background, so it doesn't come easy to me. But absolutely great job, nevertheless... I am hoping to learn and know a lot from you. :)

I'm so glad I found you, Kathy!

wonderful shows. Very illuminating (ahem...) and lively! Well done!

Thank you for this insight into the madness of man that has brought us the lunacy of QM.

Hi Kathy - loved the video. I've always felt science should be taught as a history class and here we are - subscribed!

So Einstein was enthralled with the quantitative nature of light from photoelectric effect. This led him to speculate that energy was bundled up in matter as well, and that it took certain energy states to knock loose this potential locked in matter and this is what led to e=mc^2 omg it makes too sense now. Thank you this was wonderful.

Beautiful and Inspiring !! Keep it up.

All of your videos are absolutely phenomenal. I would give triple-thumbs-up.

A very enjoyable series on scientists

I just fell completely for your videos!! You really make the science come alive. A big thank you!!

Thank you so much. I am finally filling in the gaps in this history. I have read Faraday and max. Finally I understand e=mc2 .can't get enough.

You are so interesting! So much energy in your words and smile! Such a great scientific motivator. Thanks so much for these videos!

I can believe only now yt recommended me this channel. Great content!

Nicely done. Many Thanks.

Discovered your channel about a week ago, and I am hooked! I have subscribed, I love this channel! Thank you

Excellent, I am enjoying every one of these things. That I have discovered that you've made.

Very nicely narrated story. Thanks.

Thank you for the great presentations. It sounded horrible that Einstein would talk about his own child as if she were disposable. The truth (as I understand) is that it was so common at the time for babies to die before they turned 5 that it's said parents would barley show interest in a child until they became old enough to survive. I would expect that to be more true of a father...

Pronunciation of maleva is fine... However, consider the spelling of the fine plastic dining utensil spork. I really enjoy your channel by the way.

I am really enjoying learning from you. :)

I'm very happy to have found your channel. These science videos are excellent.

Excellent blending of history and science.

Kathy, as they say in the Northeast, you're "wicked smart", but can break difficult concepts down to simpler explanations. Thanks for sharing this!

All previous comments on observables are of the relative-timing ratio-rates of resonant clocking, even the geometrical varieties were inscribed on the moving platform of the Earth in relation to the sky. (Putting what revolves around the other aside for a bit) So with the 20/20 of hindsight, Galileo's timing modulation measurements for Musicians and Mathematics made the default mechanism of transverse trancendental e-Pi Timing-spacing coordination Communication into a Cosmological significance, in particular, the motion of the Moons of Jupiter separated the Observer's POV from the temporal trajectory of remote objects. Then Newton demonstrated the importance of Corpuscles (quanta of light) and directly related idea of distance in relative-timing ratio-rates @.dt infinitesimal, (now Planck Dimensions phenomena), so now the reciprocal connection of corpuscular wave-particle coordination-identification positioning could be inverted to synthesise the relative-timing wave length. (Reciprocal-reversible Quantum-fields Mechanism becomes the alignment-> advance, towards the Holographic Principle Imagery of Singularity in Black-body, projection-drawing time-timing Actuality) So unsurprisingly, Einstein realised the quantization pulse-evolution e-inflation+/- cause-effect in the sub emulation of UV photonic pumping effect in Cathode Ray Tubes, in alignment with Newtonian Fluxion-Integral Temporal Calculus InflationCondensation cause-effect, continuous e-Pi-i sync-duration connectivity in superimposed resonances creation, ie Eternity-now here-now-forever Interval. (Not weird or mysterious once you get the idea?) Treating waves like particles is fine for Reciproction-recirculation Partitioning of conic-cyclonic coherence-cohesion vortices manifestation of sync-duration states of elemental e-Pi-i Superspin Modulation positioning where time-timing sync-duration => projection-drawing reciprocals of pulse-evolution differentiates, holography. How else could the pure-math relative-timing rates of transverse trancendental e-Pi "Musical" condensation be conceived, and be understood as Bose-Einsteinian Condensation of Spacetime and Quantum-fields Mechanism Holographic standing wave modulation crystallisation by QM-TIME, logarithmic quantization-interference Completeness? The Zeroth Law is the empirical recognition of Singularity-point positioning Conception of Reciproction-recirculation in the floating point = flat space ground state Origin of omnidirectional-dimensional cause-effect, and self-defining quantization of pure-math temporal mechanics.. (although Albert was a Pacifist, there was no safe alternative way to react to the militaristic hierarchy of the era?) ----- The short version is, the Universe is a purely probabilistic Quantum Analog Modulation Mechanism, ie wave-packaging formation. Think it through to what it means in Eternity-now Actuality Interval, sum-of-all-histories (probable WYSIWYG here-now-forever). What do you see that is recognisable in the Mirror?

Amazing as always! BTW, you look tan, rested, and ready. More videos, please!

Thanks to your videos I ve learned so much about the great scientists, especially in physics. I like your lessons because you also talk about the person and their faith. What about the great Stephen Hawkins?

Thank you Kathy for your awesome videos! I have this problem locating information on this subject, and I think she'd be the pefect person to do this. Sorry for this lengthy post, but this is related to Einstein's discovery mentioned here. It led to video tech! To make this point clear, I'm trying to find information (like RU-vid, etc) on the first "imaging devices" used in Fax machines. They're the predecessor to the CCD sensor used in most camera technology today. I read a old white paper at work, but can't find it anymore. I think it was published by Sony. Sony used to make this device (possibly a chip) with a "wire" that one charges with high voltage. Using optics, one line of an image (a document) is shined upon this charged wire. Depending on the image, the light will discharge that portion of the static charge on the wire. Oddly enough and shocking to learn (to me); this pattern of charge doesn't just reach equilibrium with itself in the wire; it just stays there; or at least long enough to use in electronics. When we allow this charge to flow, it becomes a "current", the pattern of charge in the wire can be detected from this current as a voltage. It is transmitted as a signal in real time (in old analog fax machines). The voltage goes up and down depending on whether that region of wire was exposed to the light, or not. Then do this for every line in your document and you have a fax machine. Today most of this is digital and we send the bits of information instead of an analog signal. Later they found ways to do this in silcon cells, and this is what leads to the video tech we use today; CCD/CMOS imaging sensors. The whole process of taking an image/sound from the real world and turn it into electricity (transducers) is a subject worthy of Kathy's skill and would be fascianting to watch. There are a few videos about Farnworth and RCA, and mechanical TV, etc.., but I don't think they really dive in like Kathy does. I'm curious as to how well the first telphones worked too.

Really enjoying your videos, your presentation is delightful and the historical approach insightful.

Everything in the universe is composed of music. It’s all vibrating, like a giant chorus, at different frequencies and magnitudes resulting in matter and energy dancing together endlessly.

Ok, so I was trying to study for physics and it was going well, using youtube and your videos as the first point of contact outside of the class room. Now youtube has suggested them to me I'm just watching your videos for fun, half of me wants to curse you and the other half want to applaud you. I'll stick with the applause for now.

Why didn't You Tube let me find your videos sooner? I like watching them. I have watched other physics videos by the dozens and searched quite a few physics topics but you only came up a few days ago.

A physics history question: What motivated Albert Einstein to develop his Special Theory? I can think of only two possibilities: 1. Einstein tried to transform the coordinates of Maxwell's equations with a Galilean transformation and saw that they were not covariant by that means. His conviction was that the laws of physics should be the same for all inertially equivalent observers. 2. The Michelson-Morley experiments showed that light did not travel through and ether and was constant: independent of source 's or observer"s motion. But AE does not seem to credit M-M with confirming that fact. So which or what was it that motivated AE to develop his ST of Relativity?

My brain just expanded.

Great videos, Kathy! Keep up the good work!

Kathy, I do love your lessons!! Congratulations!

The relationship biasing the particle property of any radiation to its wave nature is p = h x k, where p represents the momentum of the radiation, k its wave number and h is the Planck constant.

Another great video. I would like to see a list of your videos, so as to be able to browse them..