Complete History of the Avogadro Number
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- Опубліковано 14 кві 2022
- How did the Avogadro number happen? How did he know about molecules before they were even discovered? What is the Avogadro constant? The chemistry, physics and science of the Avogadro number is discussed in this complete history the Avogadro number, going all the way back to 400 BCE.
I had a hard time making this video. See what went wrong here: • Avogadro Number outtakes
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Thanks to Dave Borgeson for the music: Enchanted, ©Dave Borgeson
Brownian motion simulator from tinyurl.com/mrh7eszs (Andrew Duffy)
Excerpt from BROWNIAN MOVEMENT AND MOLECULAR REALITY. By M. JEAN PERRIN via tinyurl.com/52m4cxfd
Excerpt from Electricity and Matter by J.J. Thomson via tinyurl.com/bddbdz2w
Silicon sphere photograph via National Institute of Standards and Technology
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Free resources used in this video:
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This video was produced at Kyushu University and supported by JSPS KAKENHI Grant Number JP21K02904. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of Kyushu University, JSPS or MEXT.
The summary is at 32:06
Hello Sir (I realise you have not given your name anywhere in the video or in the description below, or I may have missed it),
Thanks for this excellent video. I studied chemistry in school and somehow the Avogadro's Constant - the idea that the same number of moles of any element should have the same number of atoms (if that is how one translates it) never made sense to me. It still doesn't and so turned to your video to see if I could get an answer.
I must confess I haven't followed up on this and searched for answers in the interim, and so haven't been a good student.
Can you please explain how the same volume of different gases (at same P and Temp) of the same mole (weight) have the same N, conceptually? I understand that the Ideal Gas Equation will give us that, but I was then trying to understand this in the following way:
Imagine 1 mole of H2 gas is filled in a container of volume V (at some constant P and T) and weighed and it has N number of atoms (would calling them molecules be better?).
If I fill that V (at same constant P and T) with 1 mole of another gas, say O2, and if it too has N number of atoms (molecules?)
Now since the number of the atoms/molecules is same in both the cases, if I manage to "convert" (theoretically) the number of atoms of O2 into number of atoms of H2, wouldn't the number of nucleons (and so number of atoms) increase by the relative ratio of their atomic weights?
Shouldn't N of Oxygen be more that N of H2 by their relative ratio of their atomic weights?
Weren't the early chemists relying on measurements of P, V and weights (mass) to get these findings? So, why did they not think of the problem in this way?
Why is N a constant for 1 mole of any element?
Thank you. In case you do not have the time for a video, but can point me to some online resources that will throw some light on this, I would be grateful.
@@welingkartr416 "wouldn't the number of nucleons (and so number of atoms) increase by the relative ratio of their atomic weights?"
I'm not sure whose misconception you're referring to here, so I'll assume you're talking about what's going on in the minds of the early chemists. We now know that if we could magically transform H2 into O2, the number of nucleons would change but the number of atoms would remain the same. The notion at the time, that more mass could mean more particles would have been a perfectly reasonable conjecture, but it was Avogadro and Loschmidt that drew the conclusion that this could not be the case based on the known gas laws. It was this insight that put weighing molecules (and from there calculating atomic weights) on a solid scientific footing.
"Why is N a constant for 1 mole of any element?"
Because N has now been defined as purely a number. You can use the Avogadro constant for counting anything you like, though it's only useful when you have truly enormous numbers of things (I wouldn't recommend it for counting eggs, for example). This video is about the history of how we came to choose that number rather than any other number. Have you watched my video on How and Why Chemists Use Moles?"
Wow, giving the chance to skip the video to people who might not have time for the whole thing. You are legendary my friend.
Edit: I still watched the whole thing. Cool stuff man
Kathy Loves Physics Channel and you have provided much needed explanation of historical information that is not in common texts books. Thankfully, so, because in math and science subjects should teach the specifics, not the history. I always hated the name of any very obscure name and date being tossed into the middle of a math equation test.
And miss the commentary from the peanut gallery at 5:52 ? Naaa...
This man just casually explains the history of Avogadro's number on a nice walk
As always, an excellent class that joins history, chemistry and a lot of information with a really clear oratory. Thanks for that!
Very nice video, thank you! One small mistake: it is true that Robert Brown was observing pollen when he saw the random motion of particles, but the grains themselves are way, way too large to wiggle in water. Rather, it was the dust that was formed when they were broken that did (he was looking at dried pollen from herbarium specimens). Brown at first though that the motion was of biological origin, but then experimented with other kinds of powders and found that they too wiggled in a similar way, so the phenomenon must have a more basic origin. Despite being a botanist, he realised the importance of his observation, and so published a very detailed account for physicists to consider. He wasn't even the first to see it, but was certainly the first who though it must hide something important.
Thanks for that!
Canizzaro
Gay Lussack,
Lavoisier, etc. (killed by the freemasonic French Revolution) chemistry development, history... brilliant! Thank you
I agree. But, s'il vous plait, Gay Lussac. No K. :)@@davido3026
@@davido3026I think only religious people of the past were against scientific community but if what you said is true then they can't be Freemasons they must be of some other cult. As far as I know these kind of cults are based on knowledge and experiments and there are many great scientists who were part of these philosophic groups.
Do you have any evidence of your claim?
Share it with the internet
@@Grateful92 Like there wasn't an absolutistic feudal system of oppression and arbitrary rule over centuries in place... **Facepalm**
The only evidence we have here is that there is no doubt that this davido guy has not a small problem only with history and reality ... or that he is just one of those nutcases which are physically hurt by reading books and learning. They get their knowledge from the "X-Files" (for the older under us, hehe) or modern BS like Assassins Creep and Netflix fantasy stories. Don't waste your time. Kinds like these are only interesting in clinical psychiatric studies:)
Oh and are you joking, too?:) "I think only religious people of the past were against scientific community" ... In what deep hole do you live? Don't you have newspapers? So you do know nothing about the 60% of American people doubting evolution theory (which is funny in itself as this is nothing you can doubt: It is something that describes OBSERVATIONS = Reality and tries to put those observations into a model we can predict something from ... like explanations why and how species exists. What comes tomorrow? We are doubting gravity ... or that the earth is round? ... wait a minute ... hehehehe) or fundamental christians killing women and doctors in front of abortion clinics ... because they want to "save lives". Oh and all the other absurd and horrific stuff all around the world that is done (RIGHT NOW!) in the name of their fantasy gods?
Also: Science and the scientific community simply doesn't existed back then as you and I know it today. But to see all organized people like cult members or the people back then in general as fanatics or cult members is absurd. Not much differentiates them from us. They were loving and curious humans like we with no difference in the capacity of understanding and intelligence. NONE! To call such organizations a cult is equally stoopid as calling my chess club a political think tank. Only people who are allergic to learning (look something up...) and maybe have some mental conditions are subsceptible to see in everything behind the next corner something mystic, evil or who knows what. That is nothing we can solve here in the comment section of UA-cam. This can only be treated by an expert ... at least if there is some kind of self-awareness in the first place. In short: Not our problem!
History, science, mathematics, and a nice walk too, what more could a video contain.
Left school at age 15, am now 60. Great video and your style of presentation kept me captivated and curious enough to seek reference from Google to keep up as i watched watched. I was a person with only a passing interest in chemistry. I have now subscribed to your channel. Your excellent use of history sealed the deal. 👍👍👍👍👍
My favorite high school class was chemistry and it was taught by the best teacher anyone could have. His name, Robert Frost.
Same. Jim Hackett, I'm 63 and will be always grateful even though I never 'needed' it. @@williamp9361
You are an excellent communicator. Thanks for who you are and what you do.
A few years ago I was taking a philosophy of science class to satisfy a breadth requirement for my degree in computer science. I ended up writing an essay on Jean Perrin's findings (which he published in a book, "Atoms"). What was remarkable was that he used something like half a dozen completely different experiments to estimate Avogadro's constant, and his calculated values were all surprisingly close to each other.
That's very cool. A better understanding of the history of science would I think go some way towards combatting the credulous acceptance of populists politics that is now making the world so unequal and dangerous.
This was a blast. I was fascinated with Avogadro's story but seeing it intertwine with literally most of the concepts used in contemporary science is mindblowing. Loved it!!!
This is the best, most lucid presentation I’ve seen on anything in a very long time. Well researched and thought out, clear, simple, and brief. Style reminds me of James Burke’s ‘Connections’ series.
Thank you for your work on this! Well done!
The nightmare of having to calculate the mass of elements starting from oxygen arbitrarily set to 100 makes me really wonder if some of the more difficult concepts in math and science are unnecessarily complicated by accurate but ridiculous models that work, but only a genius could grasp it.
You just described intellectual property...😢
So much of software works that way.
Honestly, scientific notations seem complicated because thats a different language. Math notations are easier to read imo than physics or chem, because i am a stat math major. But, learning to read proofs is how you proceed with learning math. Its fun, just like learning a new language. All mathematical statements are proper sentences, with conjunctions between clauses. Just like you can't know every word in dictionary, but use words aming them, you can't arbitrarily read all math topic, but some. You get better at it with practice and time.
String theory says hi
I mean, it's just a simple math problem... Especially if somebody that is educated like these guys were. But really those guys had to do routine and boring math like this. Spreadsheets sort of stuff.
Fascinating. When I was in high school chemistry in the late 50s, we were taught simply that there was this number, and that if you had that many atoms/molecules of something, you had a mole. End of discussion. And I never thought to look at the subject again. Now I'm glad I've seen your video, because I have a much better idea of how controversial, and important this number was.
this is the most amazing video about this topic that i have ever seen. thank you SO SO much for it! you're incredible!
And thank you so much for your lovely comment!
Thanks for the expansive explanation of these fundamental chemistry topics!!!! Cant wait for more. Pretty sure im going to watch every video you make!
Curious: where did you learn chemistry? Really excited about learning it for myself and really glad to find people like you along my journey
Really great and comprehensive summary. I think that Boltzmann probably deserved a mention but to be fair it’s already a pretty long video.
videos like this puts everything back into perspective. Nicely Done!!
An astounding video. I've been learning chemistry for an ample seven years now and I've never been told the story behind the mole. Thank you for compiling and boiling all that information down, I can only wonder how much effort and time was put into creating it.
This video is a gem. I’ve been wondering about the history of Avogadro’s number for many years now…. And, now I have the answer. Thank you!
Thx. I love these history lessons on science. Well done and insightful!
This is a crystal clear explanation of a concept that has always puzzled me. Moreover, I very much appreciate the "James Burke Style" of presentation walk-and-talk. Well done!
Love the clarity of thought and presentation and enunciation....was so correct one didn't have to strain to understand. Wonderful sense of history of chemistry. 🎉
That is a very well-crafted video and very informative.
I am not a chemist. So it solidified a sketchy understanding of the subject - which is a lot more interesting than I ever expected.
Well done.
I hope you ended up wherever you were going.
Thanks. You've taken me back more than half a century and given me a greater appreciation for chemistry and physics.
This talk is fantastic. Thank you sir.
Congratulations for this cristal clear presentation. I’ve finally understood what my science teacher tried in vain to explain 45 years ago. It’s never to late ! Thank you very much for helping us perceive the beauty of the scientific adventure.
Very informative! Thank you so much.
i had been trying to understand the Avogadro's number and I was having difficulties truly understanding it until I viewed your video. My hat off to you ! Very well done! Thanks for helping me "remove this flee from my ear"!
Great teaching of a fascinating history. Thank you.
Very interesting and informative!! Thanks!!
What a nice summary! Thank you!
Thanks for all the research you had to do on this topic.
As already noted in a commentary, Loschmidt is not mentioned. He gave in 1865 the first estimate of the number of Avogadro. Maxwell spoke about it and called it the Loschmidt constant. In Austria and Germany, the Avogadro number is also called the Loschmidt constant.
I have no idea what youre on about here to start, but you hooked me with the intro. Fell into a learning hole again, learn me good.
Excellent video ! 10+++ It clears important milestones about how the number of Avogadro was calculated and, arguably astonishing enough, that it was not Avogadro who calculated the number, he only introduced the concept.
As someone who was learning high school chemistry in the seventies. I was flabbergasted to learn that these issues that were dryly presented as settled science were still being debated in 1971. I also had no idea that the very existence of atoms and molecules was up for debate at the beginning of the 1900’s. I also have no idea what I was taught was the value of Avogadro’s number was but to discover it continued to change until a few years ago is really remarkable. Thank you for doing this video and I am so glad that I decided to click on this!
As another old-timer who took HS chemistry in the mid-70's I had exactly the same thoughts. When one is a teen I guess one tends to think of all past scientific progress as dead and dull.
This is the first time since the early 60s that I have encountered Avogadro’s number. I was astounded then and am astounded now to learn that it has changed.
Your explanation was awesome, thank you!
Great UA-cam! Thank you. The most fascinating and painless science history lesson I've had the pleasure to experience!! Looking forward to your next youtube. PS. Was that somewhere in Africa where you were videoing? Loved the natural scenary.
This is the best explanation of the origin and history of the Avogadro number that I have ever heard! Thank y-o-u-u-u
Excellent. I really enjoyed that.
Fantastic, fantastic recap of a fantastic story. You won another suscriber
Excellent video! Very informative, and you have a great communication style.
Excellent explanation on Avogadro`s number i ever watched , it really helped me lot . I really appreciate your effort sir 👍😊😊. I really like this this kind of deep explanation on a single topic with simple language , keep it on .
Excellent video. Great presentation, thank you.
This is a great video, I've just added it to my favourite playlist.
Thank you so much for this video. I kept wanting to find the source for the number and everything I read was either incomplete or wrong. Although, after this video I can see why. You gave such a complete and thorough explanation and easy to follow. Thank you once again.
I'm glad you enjoyed it!
"It turned out to be a lot more complicated than I thought". Damm, you have me now.
Excellent work.
Excellent presentation, combining two of my favorite topics, science and history, but you had me wondering about halfway through whether you were approaching this from a chemistry or a physics perspective. Towards the end, it was revealed that I had intuited the right question, as that was the crux of the dilemma that had to be resolved.
Fascinating video, I had no idea about the history behind L. Thanks for this.
Thanks. I literally thought it would only take 10 minutes when I started. 😄
Great video. Watched start-to-fini
Thank you for the update🧘♂️👀, yes very helpful
Fascinating!!! Thank you for that semi-scientific-historic review on top of your unique style.
Muito obrigado pelo seu trabalho!
Great lecture. Thanks.🙂
Thank you for an amazing explanation of the Avogadro number!
Finally, all is revealed. Fantastic video.
Just found your channel. Very impressed that you recorded this from memory (no notes?) and all fluidly.
Amazing understanding, highly engaging.
You have really done your homework ! Outstanding summary of a complicated history . I wish I had seen this when I was doing 1st year Chemistry - it chewed away at me as to how they “ knew “ Hydrogen had an atomic weight of 1 - or whether it was a best guess - and it was !
Brilliant! Thank you, thank you x
A wonderfull explanation of a complex issue
Very well explained.
I have a Degree in Physics and much more in EE, declining a PHD at Stanford in California but continuing at Berkley. I suffered in Chemistry in high school when the numbers changed, and it was still a bit mysterious. I very much enjoyed your presentation and talk. Thank you so much.
I'm a newby, delighted to find this channel, and freshly subscribed. A quick search shows nothing more on Perrrin in your videos, and I'd love to hear more about his experiments and "proofs" of atoms and molecules. Where might I look? Thanks - I see a lot here to explore!
Excellent, well explained !
I've always wondered how Avogadro's number was fixed, and your video gives the most comprehensive explanation I have ever heard about the subject. I recall being confused about the concept of gram-atom and gram-molecule and how they related to the mole, and your explanation cleared that mess up for me. When asked to produce Avogadro's number from memory, I immediately say 6.023 x 10^23 and then correct myself to 6.022 x 10^23. Probably says a lot about what the value was when I learned chemistry.
I understand the ideas behind Brownian motion as supporting evidence for the existence of atoms, but I think that the development of atomic spectroscopy and mass spectometry are more convincing evidence for the existence of atoms and molecules.
This was an excellent video with a very clear explanation of the development of a set of very fundamental concepts. Thank you for making and sharing it.
Very fascinating. You took me back to some 50 plus years ago when as a little country boy in St.Vincent I started reading chemistry by one named ?Bell. Its is remarkable that the methods used many many many hundreds of years ago and now are still in the 6 x 10^23. The subject is fascinating.Still a lover of Chemistry....Everything in the body depends on it! Bless you for such a great job! Big Thanks to you!
Hey this is great. I did a much shorter video on Avogadro's Number, so I appreciate the deeper dive. I thought it was cool how you pointed out that Perrin formalized calling it Avogadro's Number, but it had been used in practice well before that. Didn't know that!
Thanks! I'd only intended a ten minute video myself but I couldn't stop. 😄
@@ThreeTwentysix and it turned out great 😂
The history of science is full of those happy instances where some principles were used by intuition until someone else gave it a name, nothing wrong with that!! That way, the discovery was uniquely identified!
As a college student, I never imagined I would find a topic like this interesting when I was about to turn 76. Thank you for a great presentation.
Yours truly,,
A new subscriber
Same @@prapanthebachelorette6803
wow, depth of research & gr8 explanation
Thank you, I appreciate it!
Well done, thanks!!
Nice explanation!
You make things so clear wonderful A +++
The surroundings and the science, wht a beautiful combination ❤. Excellent work
Outstanding "explainer" video! It was actually quite enlightening for me, having last taken Chemistry in college in 1966, how *recent* much of this was.
Excellent video! You now have a new Geophysicist subscriber.
Very good presentation of the notion of mole and Avogadro's Number as they evolved from the early crude perception and evolution to the current definition and accurate measurement by experiment through the contribution of so many chemists and other physicists!
Merci pour cette riche vidéo! Une promenade et un café en intelligence et pédagogie. J'ai gagné ma journée !
Thank you very much for the Wonderful description of a very less taught fundamental topic in science.🙂
Fantastic video. Loved it (apart from weight versus mass)
That was damn good man!...
Simple and excellent 👍👍👍
enjoyed it, thanks
This is most interesting to me as a physicist. Thank you for putting all of this information together.
Thank you for this.
It was so informative.
Really enjoyed this. The first time I learned about molar mass and atomic numbers, I was flabbergasted at how useful these concepts are for practical chemistry. I also enjoy history so this presentation hit me just right! I'm the type that sees The Voyage of the Beagle as an illumination of evolutionary theory.
Let us also take a minute to appreciate Mr Bacon's contribution to the culinary world. Sincerely, from the bottom of my heart, i love you for what you did, Mr Bacon.
This was great, thanks
Thanks for watching!
Just delightful!
Tremendous. This is what education needs. Well done my friend.
Super Class! Great. Chemistry! Great. Presentation! You learn me something!🎈🎈
Amazing story. Thanks for telling it. What i found surprising is that many fundamental discovery's that make up modern chemistry are less then 100 years old.
I just now stumbled upon this channel. Pretty interesting. I'm willing to chip in to buy Dr. Andrew a hair comb.
I have a degree in chemistry and this talk really nailed the events leading up to the mole standard that I have used so often. Thanks for giving us your time in such a fashion"
Thank you for posting your video. I enjoyed the Educational history lesson.
Rock on.👍🇬🇧KCB.
Excellent. ¡TOP OF THE CASS EXPLANATION!
Hi, new to your channel and I’m already hooked. Are you in Japan in this video? It reminds me of videos I’ve seen from my friends that live there! Fantastic video, it’s 1:30am atm so I can’t get anymore creative in my comment lol
I found your channel from this video. I have subscribed, but not yet browsed your other videos, yet. I did want to provide a thought for you. There is a gap in media in science programs for the general public and science programs for science people. This video is a great example. I compare and contrast to James Burke's Connection series. Compare: follow a thread throughout history on how a certain modern thing came to be. Contrast: His was meant for a general, albeit educated, audience. I am a theoretical mathematician by education, but working towards my Ph'D in Astrophysics. Missing from a lot of my education was the history behind a lot of this stuff. In a BA in Mathematics, my alma mater required a History of Mathematics course. As I got a BS, the course was not required.
I would love to see someone fill that gap: Make Connections-like content detailing the history of something in science, but with the expectation that the audience already knows the science. What you have done in this video is closer to that than I have seen and I think you would do well with it.
Thank you for an excellent video! Avogadro's number is something that has been in the back of my mind since I left school - 62 years ago. I never quite understood how it could be worked out - I do now! (on to moles - another slightly grey area)
I was familiar with most (but not all) of the characters, but you threaded them together in a convincing, understandable way that I haven't seen before - great job!
I know you can't take the time to name all the players who contributed every little bit along the way, but I recently discovered one that I think would've been worth mentioning: Lucretius (~60BCE) observed Brownian motion in dust and used atomic theory to explain it. Check out the Wikipedia article on Brownian motion (that's not where I discovered it, but it gives context and a good summary). Lucretius was a remarkably insightful dude in a lotta ways.
Good video. It's a complete explanation
Thanks!