I am 40 years old. Never had an interest for physics. That have change thanks too you Walter Lewin ! I have now watched most of your youtube lectures. And things that was for me very difficult, now seems understandable. Thank you !
When I saw thumbnail and read title so I thought now proffecor Walter Lewin will teach us a english literature because in our country India in the ncert english beehive has this chapter the sound of music
Haven’t aged a day Walter, wonderful lecture, as usual. Being able to explain something so literally everyone can understand it clearly is the test of a true educator. If you can’t explain the truly difficult in a easy way then you don’t understand it at all.
Partial hearing loss/ old age confirmed, and now, I'm having a crisis! He reminds me of my physics (without calculus, thank goodness!) professor at USF. I really looked forward to each lecture, and retained the information well, which is something I'm not as good at as I used to be, but the lectures brought the information to life, and gave me multisensory references to go back to when I needed to recall it. Professor Lewin evokes that same feeling in me. It's wonderful to watch someone teach something they're passionate about. Now, my daughter is starting college soon, and I hope she finds some awesome professors like him!
An amazing lecture with marvelous displays of physics in action and the basics of what we hear and why we hear it. For musicians and the listeners alike. Audience participation is a joy. The entire video is jam packed with information.
This recorded lecture will serve humankind understanding of the sound and its characters to the infinite time period....Sir, please make sure these videos are also available on different platforms so that if in future something wrong happens with TH-cam still your videos will be available to all human beings. Your videos are priceless. Valuable than any gems available on this Universe.🙏🙏🙏🙏🙏🙏Earth needs your creations forever.
Professor! I am a Music Producer, and I am even more inlove with music knowing that they are so complicated yet beautiful. Thank you for this wonderful lecture!
I found you lately but Thank you Sir. Your every lecture I have watched, are awesome. It adds new knowledges to me also refurbrishes my old knowledges. I liked Physics during my school and college. Now you made me love it. Thanks again sir. 😊
I really enjoyed this lecture although physics is not my subject but I really understood almost everything and I loved to see the children's playing with different instruments and the end of the lecture they really had enjoyed the whole session. 👏
Awesome! Prof. Lewin, your lectures are simply amazing. I know they take an enormous effort to design and prepare. Please consider publishing a "guide" for teaching physics including both your amazing lectures as well as the setups for your incredible demonstrations in 8.01, 8.02, and 8.03. I am sure many students would benefit from professors and lecturers learning how to teach physics in such an engaging way. Thanks again for a fun little lecture!
Thank You Very Much Sir..I am from India.I always want to like you as a teacher , but I never got this. Your lecture always make me inspired and my knowladge is zero. I get more energy from your teaching..
Professor, your lectures are brilliant, entertaining, and inspiring. I teach history, but I have always loved physics and astronomy. Thank you for challenging my mind and making me smarter! Would love to teach physics or astronomy, if only I was better at math!
Prof Lewin, this is so inspiring to me as a prospective teacher. Hopefully I will be able to enthuse my pupils in a similar way you did. I think that people can become more courageous for thereselves, each other and the environment if they are shown how fascinating this world can be - just because of the right point of view.
Thank you so much sir for explaining. But, the clouds, that you have explained, look red at night.Is this for Raleigh Scattering (size of the molecules are still >>larger than tenth of micron)? how does these clouds appear from an airplane?
Lectures by Walter Lewin. They will make you ♥ Physics. sir, I am a physics teacher. I love your style of teaching very much. I am trying to teach my students like your style.I know it is not that much good like you but I am trying....I also have "Love of Physics"...I have no word to describe your book....you are my inspiration of physics teaching....
Wish all of my teachers were like this. So inspiring and also fun, I remember all of the things this prof. explained, whereas when my teachers speak I can't catch a fly
Hello professor, I'm a lover of physics and of yours lectures. I'm a brazilian ,17 yo, that got inspiration on you to begin my phisics graduation on Universidade Federal de Minas Gerais this year, thank you for all of those wolderfull lectures !! (sorry for my bad english haha)
Thank you professor for this amazingly beautiful demo of the holy harmonics❤ Btw, That Joseph kid was 13yo, I was 3yo then. That makes my thoughts very unorganised right now.
I'm 18 years old. But after he changed 12khz to 14khz I could understand nothing cuz my ears were already screaming even though I had paused the video. And it still does holy crap
Amazing lecture. I've been studying sound for years and it's the first time i see such a clear presentation on the physics of it. The experiments particularly contribute to a full comprehension. (at 45:15 the first sound is the 3rd harmonic, but no big deal :P )
Lectures by Walter Lewin. They will make you ♥ Physics. The reason i think it's the 3rd harmonic is the interval between that tone and the lowest one, which is a perfect fifth (relation 3:2). If the two tones were 1st and 2nd harmonic, shouldn't the interval be an octave (2:1)? I think the question leads to the definition of the harmonic series. Should we refer to the number of harmonic based on the relation to the fundamental (counting all the integers between...) or should we refer only to the ones that actually resonate with the instrument? I noticed that in the case of the closed wind instrument, although the series are f, 3f, 5f...etc, we label them as 1st, 2nd and 3rd. Thank you for the answer.
Constantine You may be right. However, in general before each "sound lecture" I measure the frequency with an oscilloscope. The lowest tone I can excite with these tubes is not the fundamental of the tube but it is the one that follows. I call that freq the 1st harmonic. Some books call that the 2nd. It's easy to calculate the fundamental as we know the tube is open on both ends and we know its length. However if you think that in this lecture my lowest tone was 2 steps above the fundamental, I trust you.
Lectures by Walter Lewin. They will make you ♥ Physics. If we consider the full harmonic series, the lowest tone would be the 2nd harmonic, so 1 step above the fundamental. My curiosity was about the naming convention, since most books and articles i've read on the internet mention a static harmonic series, in which the nth harmonic is based on the relation n*f (i assume that we could always produce the fundamental in principle). Thank you for the clarification. I hope i'll study all Physics I: Classical Mechanics soon. ;)
Constantine There are 2 naming conventions. However, in BOTH conventions the "fundamental" is the lowest resonance frequency. In one convention the fundamental is also called the 1st harmonic, If the fundamental is 300 Hz, then in one convention 300 Hz is called the first harmonic and 600 Hz the 2nd (open open pipes). In the other convention 600 Hz is called the 1st harmonic. This is confusing. I believe in 8.03 I call the 300 Hz the 1st harm which is ALSO called the fundamental. It's the "n" in the equation in the resonance frequencies that is 1 for the fundamental and 2 for the next freq. n cannot be zero.
Your lectures are really inspiring. I like a music demonstration in your class and I am thinking of one man that you might need to invite him to your class.
When he said he went to thirty, my brain thaugt he actually did so my brain raised the pitch instead of stopping, then I paused the Video and it was still there... It's still there now and won't go away... Oo
Sir, when we stand in front of the glass of a door, we can see the the trees and the outer nature, as well as we can see our own reflection ( though not very clear) on the glass. Is this for the reason that for normal incidence of light, most of the rays goes straight through the glasses and a small amount ( only about 4%)is reflected?
Thank you Pythagoras. Yes, the guy with a2+b2=c2.However that doesn't explain why the 7th harmonic sounds very odd even though it is mathematically correct...
Note frequency counter readings too from video : Pitch fork 256.56 Hz -.62, the next one is flat of A 440, 424.39 -.42 Hz : the young man on the key board was playing the G key 391.47 to .48 Hz. , you can find the frequencies between each musical half step using an additive function where the note your on in Hz call it A 440 for discussion sake multiplies by a constant (.05946304 ) = 26.16376136 + A 440 = B 466.16376136, you will find that if you go up or down through the chromatic scale starting any where, the result will be the next octave up or down. To go down in frequency simply invert the sine + to -. Have fun !.
The break time was completely made to do research on their own see how they were doing their individual research on that time.We Indian also like this after our teacher finished the class😁😁😁
I study law but I'm watching a lecture of physics. But its such a fresh presentation! I'm afraid that I will spend to much time for study physics instead of law. ^^
Sir, I have a question. You have said that only if the size of the particles in the air medium are smaller than the tenth of a micron the Raleigh Scattering occurs, for which we can see the blue sky,the red appearance of the sky during sunset, etc. And when the particles are larger than this size, the Raleigh scattering does not take place further and white light remains white like the white clouds floating...which you have demonstrated with cigarettes. Sir, when in the morning the sky becomes cloudy, thunderstorms and lightening occurs, at that time, the size of the molecules in the cloud are greater than tenth of a micron, due to the accumulation of more water molecules, so it should look white, but why does it appear grey(light or dark)?
>>> larger than this size>>> Much larger than this size. Not "just larger" When you fly above clouds they are ALWAYS white. If a cloud is very thick lots of sunlight is absorbed (it gets dark). Thus if you look upwards from Earth, the cloud looks dark. But that same cloud looks white as seen from above (airplane)
Thank you so much sir for explaining. But, these clouds look red at night.Is this for Raleigh Scattering (size of the molecules are still >>larger than tenth of micron)? how does these clouds appear from an airplane?
I can tell that you are the person who changed my views on physics completely! Thank you, you're a great inspiration! If there really is such thing as emotional resonance, then you surely know a secret of finding your audience's first harmonic (:
the width of the tube is important. If it is too small or too wide it does not work, Whenever it works the frequency is closely the same and almost exclusively determined by the length.
+Lectures by Walter Lewin. They will make you ♥ Physics. so the width/radius is needed to "guide the sound wave" inside the instrument! this neans width is related to sound power transfer effeciency... just like impedance matching in antenna theory!
Thank you very much Professor Lewin. I wish I have seen your videos long time ago. As you said sometimes a person doesn't like the subject because he/she has bad teacher. I had a bad teacher so he made him hate the Physics. But watching your video it makes me want to study Physics again. And I have a question regarding to one of the instrument. When I was a kid we had some musicians who would play wood flute. When they play for about an hour so maybe a little bit longer non-stop it would started to get ripped. Since the frequencies didn't change much. Why do you think that flute tube with get ripped or broke? Veel dank!
45:34 He confused the first overtone for the first harmonic. It's the first overtone but second harmonic. He called the second harmonic the fundamental which is the first harmonic.
Hi sir. My name is Mahesh and i am from India i came across a problem while studying rotational mechanics that when we rotate a ring by our finger it rotates in horizontal plane but net torgue about finger is not zero. Who balances the torque of mg.
@@lecturesbywalterlewin.they9259it's not the ring that we wear in finger it is a circular structure of diameter 8cm in which mass is distributed along circumference. You can check jee adv 2017 ring problem. Thank u
Sir, there was a video in you tube where one claimed that in his camera he had recorded a sudden appearance of green flash in the night sky for a second (if you type at google the word "green flash in sky" you will get the video). I am not sure if this video is fake or real...but if it is real, will you please explain what is the reason behind such sudden flash?
I am unaware of green flashes at nite. But maybe they have been seen. The GREEN FLASH (google it) is associated with sun sets. I have seen it several times in my life.
Hello Prof, Lewin. I am Angga, studying in Indonesia. Can you give the physical explaination for the difference betwen betwen musical sounds and noise?
+Lectures by Walter Lewin. They will make you ♥ Physics. Thank you for the reply.but it is less helpful to me. what are the characteristics and the definition of noise?
Lectures by Walter Lewin. They will make you ♥ Physics. Haha, that's a good joke! At the end of the lecture there are some kids "checking if they have a brain" with the tuning fork lol
Education in the 90s was awesome! Thanks, Prof!
My pleasure!
Oh my god, this was 20 years ago, and now you still look the same as then! Time can do nothing to the greatest professor of all time :)
+Pavle Nikacevic Thank you for your wonderful note.
Absolutely amazing. Best hour and 45 minutes I've ever spent.
+MrRubik234 Super! There are many other videos that yu may LOVE 2
I am 40 years old. Never had an interest for physics. That have change thanks too you Walter Lewin ! I have now watched most of your youtube lectures. And things that was for me very difficult, now seems understandable. Thank you !
+Vegard Sætre Wonderful! That's very rewarding.
Professor,Evertime I watch your courses I could feel how beautiful physics is
:)
I love this man. He's an amazing professor. As a professor myself, I can only watch in wonder.
Amazing lecture, first time seen sound with eyes,
Glad you liked it
How wonderful waves are.....I can just awe.....
When I saw thumbnail and read title so I thought now proffecor Walter Lewin will teach us a english literature because in our country India in the ncert english beehive has this chapter the sound of music
the best prof I have ever seen in my life. I wish I all prof explain things like him.
+Arif Omer Thank you Arif
i'm a teaching assistant at ain Shams Uni, you are my hero you gave the hope again to still teaching the physics to the students. HOW WONDER ARE YOU
thank you for your kind words
Amazing - Must see for everyone - Loveed every sec of it. Thank you Prof. Lewin.
+RENIBUS You are welcome! There are many other videos that you may LOVE 2.
i am an 19 Year old Indian engineering student . all your lecture just make physics sound very intresting ... thanks a lot.. sir
+roaring loin you are welcome
This is such a wonderful lecture and I feel so lucky to be able to watch this. Thank you a thousand times and wish you good health and all the best
haven't ever seen anyone with such a fervour and belief in science
I just found this video and it put a big smile on my face. You are Wonderful Walter 😃
:)
I am a violinist and violin makes much more sense to me after this lecture.Awesome Lecture !!.
Haven’t aged a day Walter, wonderful lecture, as usual. Being able to explain something so literally everyone can understand it clearly is the test of a true educator. If you can’t explain the truly difficult in a easy way then you don’t understand it at all.
thank you so much Professor.
Very fundamental to understand sound it's characters. I cleared all my doubts after watching this
outstanding explanation
thank you for your lovely lectures ,you make me love learning again
:)
This is an amazing video. Thanks a million Professor Walter Lewin.
+Mahmoud Shalaby Thank you!
My 9 year old son diligently watches your videos. He is now going through the 8.01 series. Thank you for the videos.
I love your classes and i love you mister Levin.
Partial hearing loss/ old age confirmed, and now, I'm having a crisis! He reminds me of my physics (without calculus, thank goodness!) professor at USF. I really looked forward to each lecture, and retained the information well, which is something I'm not as good at as I used to be, but the lectures brought the information to life, and gave me multisensory references to go back to when I needed to recall it. Professor Lewin evokes that same feeling in me. It's wonderful to watch someone teach something they're passionate about. Now, my daughter is starting college soon, and I hope she finds some awesome professors like him!
Thanks for your very kind words. I too have partial hearing loss so we have something in common.
An amazing lecture with marvelous displays of physics in action and the basics of what we hear and why we hear it. For musicians and the listeners alike. Audience participation is a joy. The entire video is jam packed with information.
+Joshua Silverman Thank you Joshua
Really really amazing... This is the most amazing hour and 45 minutes in ever in my life... Tnq proffesor... Really a huge fan of you!!!!!!!!
Magnificent!!
This recorded lecture will serve humankind understanding of the sound and its characters to the infinite time period....Sir, please make sure these videos are also available on different platforms so that if in future something wrong happens with TH-cam still your videos will be available to all human beings. Your videos are priceless. Valuable than any gems available on this Universe.🙏🙏🙏🙏🙏🙏Earth needs your creations forever.
Professor! I am a Music Producer, and I am even more inlove with music knowing that they are so complicated yet beautiful. Thank you for this wonderful lecture!
I found you lately but Thank you Sir. Your every lecture I have watched, are awesome. It adds new knowledges to me also refurbrishes my old knowledges.
I liked Physics during my school and college. Now you made me love it. Thanks again sir. 😊
That is a very nice class! Thanks!
Great lecture! thank you Professor Lewin you're amazing teacher :)
+Zohar Avigal thank you
I really enjoyed this lecture although physics is not my subject but I really understood almost everything and I loved to see the children's playing with different instruments and the end of the lecture they really had enjoyed the whole session. 👏
Awesome! Prof. Lewin, your lectures are simply amazing. I know they take an enormous effort to design and prepare. Please consider publishing a "guide" for teaching physics including both your amazing lectures as well as the setups for your incredible demonstrations in 8.01, 8.02, and 8.03. I am sure many students would benefit from professors and lecturers learning how to teach physics in such an engaging way. Thanks again for a fun little lecture!
love you Sir Walter Lewis
I proud of you ,your really best physics teacher you can do every things of Physics in practically
love you so much
Thanks for this wonderful lecture professor
Thank You Very Much Sir..I am from India.I always want to like you as a teacher , but I never got this. Your lecture always make me inspired and my knowladge is zero. I get more energy from your teaching..
wonderful
Greatest ever 💕❤️🙏
Amazing lesson!!!
+Edmund Out thank you
best best and the best lecture
:)
Professor, your lectures are brilliant, entertaining, and inspiring.
I teach history, but I have always loved physics and astronomy. Thank you for challenging my mind and making me smarter! Would love to teach physics or astronomy, if only I was better at math!
+AbsoluteyAmerican Thanks for your kind words.
Wonderful
Prof Lewin, this is so inspiring to me as a prospective teacher. Hopefully I will be able to enthuse my pupils in a similar way you did. I think that people can become more courageous for thereselves, each other and the environment if they are shown how fascinating this world can be - just because of the right point of view.
:)
You are the best prof ever..........
+Dida A M Thank you Dida
Amazing vedio
Simply Awesomesauce.
how can i be amazed like you you are the best teacher i have ever seen
what are books do you advise me to read about experments
any college physics book will do. calculus based.
Thank you so much sir for explaining.
But, the clouds, that you have explained, look red at night.Is this for Raleigh Scattering (size of the molecules are still >>larger than tenth of micron)? how does these clouds appear from an airplane?
its just waw....many many thanks for uploading this video....
you are welcome
Lectures by Walter Lewin. They will make you ♥ Physics. sir, I am a physics teacher. I love your style of teaching very much. I am trying to teach my students like your style.I know it is not that much good like you but I am trying....I also have "Love of Physics"...I have no word to describe your book....you are my inspiration of physics teaching....
Thanks Sudipta for your kind words.
Wish all of my teachers were like this. So inspiring and also fun, I remember all of the things this prof. explained, whereas when my teachers speak I can't catch a fly
+Guido Freire Why would you want to catch a fly?
Lectures by Walter Lewin. They will make you ♥ Physics. It's a way of saying that I don't understand s***
+Guido Freire ha ha ha
Hello professor, I'm a lover of physics and of yours lectures. I'm a brazilian ,17 yo, that got inspiration on you to begin my phisics graduation on Universidade Federal de Minas Gerais this year, thank you for all of those wolderfull lectures !! (sorry for my bad english haha)
+Nicolas Heringer Good luck on your Physics studies!
I alwais hated physics. From the moment I started whatching your lectures my opinion is drastically changed. Thank you, professor. Thank you.
Thank you professor for this amazingly beautiful demo of the holy harmonics❤
Btw, That Joseph kid was 13yo, I was 3yo then. That makes my thoughts very unorganised right now.
i love you walter ❤❤❤
:)
this is excellent! will be sharing with my kids. Thank you. much better than certain other celebrity "science" guys.
I'm 18 years old. But after he changed 12khz to 14khz I could understand nothing cuz my ears were already screaming even though I had paused the video. And it still does holy crap
Amazing lecture. I've been studying sound for years and it's the first time i see such a clear presentation on the physics of it. The experiments particularly contribute to a full comprehension. (at 45:15 the first sound is the 3rd harmonic, but no big deal :P )
Constantine I believe the first sound is the 2nd harmonic.
Lectures by Walter Lewin. They will make you ♥ Physics. The reason i think it's the 3rd harmonic is the interval between that tone and the lowest one, which is a perfect fifth (relation 3:2). If the two tones were 1st and 2nd harmonic, shouldn't the interval be an octave (2:1)?
I think the question leads to the definition of the harmonic series. Should we refer to the number of harmonic based on the relation to the fundamental (counting all the integers between...) or should we refer only to the ones that actually resonate with the instrument? I noticed that in the case of the closed wind instrument, although the series are f, 3f, 5f...etc, we label them as 1st, 2nd and 3rd.
Thank you for the answer.
Constantine You may be right. However, in general before each "sound lecture" I measure the frequency with an oscilloscope. The lowest tone I can excite with these tubes is not the fundamental of the tube but it is the one that follows. I call that freq the 1st harmonic. Some books call that the 2nd. It's easy to calculate the fundamental as we know the tube is open on both ends and we know its length. However if you think that in this lecture my lowest tone was 2 steps above the fundamental, I trust you.
Lectures by Walter Lewin. They will make you ♥ Physics. If we consider the full harmonic series, the lowest tone would be the 2nd harmonic, so 1 step above the fundamental. My curiosity was about the naming convention, since most books and articles i've read on the internet mention a static harmonic series, in which the nth harmonic is based on the relation n*f (i assume that we could always produce the fundamental in principle).
Thank you for the clarification. I hope i'll study all Physics I: Classical Mechanics soon. ;)
Constantine There are 2 naming conventions. However, in BOTH conventions the "fundamental" is the lowest resonance frequency. In one convention the fundamental is also called the 1st harmonic, If the fundamental is 300 Hz, then in one convention 300 Hz is called the first harmonic and 600 Hz the 2nd (open open pipes). In the other convention 600 Hz is called the 1st harmonic. This is confusing. I believe in 8.03 I call the 300 Hz the 1st harm which is ALSO called the fundamental. It's the "n" in the equation in the resonance frequencies that is 1 for the fundamental and 2 for the next freq. n cannot be zero.
Its remarkable he can draw a straight line without a ruler.
Your lecture is amazing sire🔥🔥🔥
Your lectures are really inspiring. I like a music demonstration in your class and I am thinking of one man that you might need to invite him to your class.
too addictive ,woah
Amezing!
+Mike Wencl Thank you Mike
When he said he went to thirty, my brain thaugt he actually did so my brain raised the pitch instead of stopping, then I paused the Video and it was still there... It's still there now and won't go away... Oo
+Nexo Games | NXO very cool!
Lectures by Walter Lewin. They will make you ♥ Physics. I don't think this is cool, cause my brain tricked me ;o;
Wow I thought physics was just a subject to cram but you and your channel made me fall in love with it❤
:)
I'm 52yrs & can hear up to 20,000 Hz.
+damn dogg wowwwwww that is fantastic!. I am 79.9 and I can't hear anything above 5000 Hz. Let me know how you will be doing when you are 79! ha ha ha
جميل جداً.
شكرا
6:38 (actually 427 Hz not 440 Hz) I edited to add the next one as well which is 4096 Hz, an octave of 256 Hz.
Sir, when we stand in front of the glass of a door, we can see the the trees and the outer nature, as well as we can see our own reflection ( though not very clear) on the glass. Is this for the reason that for normal incidence of light, most of the rays goes straight through the glasses and a small amount ( only about 4%)is reflected?
yupe
Thank you Pythagoras. Yes, the guy with a2+b2=c2.However that doesn't explain why the 7th harmonic sounds very odd even though it is mathematically correct...
Note frequency counter readings too from video : Pitch fork 256.56 Hz -.62, the next one is flat of A 440, 424.39 -.42 Hz : the young man on the key board was playing the G key 391.47 to .48 Hz. , you can find the frequencies between each musical half step using an additive function where the note your on in Hz call it A 440 for discussion sake multiplies by a constant (.05946304 ) = 26.16376136 + A 440 = B 466.16376136, you will find that if you go up or down through the chromatic scale starting any where, the result will be the next octave up or down. To go down in frequency simply invert the sine + to -. Have fun !.
students never regret paying fees for such incredible lectures
+shakwi ss Thank you!
Amazing lecture, taken into account I'm not qualify or economically ready to go to MIT .
this was a talk for kids - no for MIT students.
OMG it is the best experimental class
It was uploadet on my birthday :D
And the cam got a little trouble picking up the stroboskope :)
The break time was completely made to do research on their own see how they were doing their individual research on that time.We Indian also like this after our teacher finished the class😁😁😁
professor,your daughter was genius .34:01 this model is one of the folk song instruments of BANGLADESH, my country. Here, it is called "The Aktara"
Thank you Professor. Does the sand on plate demonstration in some way related or represent a classic simulation of quantum resonance?
Ps. After watching your lecture on polarization of light, I couldn't stop playing with my sunglasses... If only I'd have known then what I know now...
NO not at all
This is classical physics resonance
I study law but I'm watching a lecture of physics. But its such a fresh presentation! I'm afraid that I will spend to much time for study physics instead of law. ^^
+Boku Kae I will make you LOVE Physics whether you like it or not.
+Boku Kae A lawyer studies physics...THATS A CRIME!!! xD
+Walter Sach It's a CRIME not to!
At 1:15:05 , why we hear a higher tone from mr jone ?
Sir, I have a question. You have said that only if the size of the particles in the air medium are smaller than the tenth of a micron the Raleigh Scattering occurs, for which we can see the blue sky,the red appearance of the sky during sunset, etc. And when the particles are larger than this size, the Raleigh scattering does not take place further and white light remains white like the white clouds floating...which you have demonstrated with cigarettes. Sir, when in the morning the sky becomes cloudy, thunderstorms and lightening occurs, at that time, the size of the molecules in the cloud are greater than tenth of a micron, due to the accumulation of more water molecules, so it should look white, but why does it appear grey(light or dark)?
>>> larger than this size>>>
Much larger than this size. Not "just larger"
When you fly above clouds they are ALWAYS white.
If a cloud is very thick lots of sunlight is absorbed (it gets dark).
Thus if you look upwards from Earth, the cloud looks dark. But that same cloud looks white as seen from above (airplane)
Thank you so much sir for explaining.
But, these clouds look red at night.Is this for Raleigh Scattering (size of the molecules are still >>larger than tenth of micron)? how does these clouds appear from an airplane?
I can tell that you are the person who changed my views on physics completely! Thank you, you're a great inspiration! If there really is such thing as emotional resonance, then you surely know a secret of finding your audience's first harmonic (:
Thank you ;)
for wind instruments, does the cross section radius affect the produced frequency or power? any effect at all?
the width of the tube is important. If it is too small or too wide it does not work, Whenever it works the frequency is closely the same and almost exclusively determined by the length.
+Lectures by Walter Lewin. They will make you ♥ Physics.
so the width/radius is needed to "guide the sound wave" inside the instrument! this neans width is related to sound power transfer effeciency... just like impedance matching in antenna theory!
In 8.03 I derive the exact resonance frequencies for a box with sides a b and c.
That may help you. th-cam.com/video/fBymt2p-ALo/w-d-xo.html
Thank you very much Professor Lewin. I wish I have seen your videos long time ago. As you said sometimes a person doesn't like the subject because he/she has bad teacher. I had a bad teacher so he made him hate the Physics. But watching your video it makes me want to study Physics again. And I have a question regarding to one of the instrument. When I was a kid we had some musicians who would play wood flute. When they play for about an hour so maybe a little bit longer non-stop it would started to get ripped. Since the frequencies didn't change much. Why do you think that flute tube with get ripped or broke? Veel dank!
Oh en gelukkig nieuwjaar!
+Mem Alan Ik heb geen idee waarom aan houten fluit dat doet. Ook een gelukkig 2016 voor jou!
+Lectures by Walter Lewin. They will make you ♥ Physics. Ik kan geen Nederlands spreken zeer goed. Ik kan een beetje begrijpen :)
45:34 He confused the first overtone for the first harmonic. It's the first overtone but second harmonic. He called the second harmonic the fundamental which is the first harmonic.
yes I am fully aware of that. Many people over the years have pointed that out to me.
your videos are too addictive.
:)
Hey the date written there is my birthday ☺️ today I enjoyed two lovely things...
Happy birthday!
@@lecturesbywalterlewin.they9259 thank u very much sir , so much respect from India ☺️
Hi, love the lectures. Does anyone know what was the violin kid playing ? 1:00:10
+Gambrinus "It almost made me cry"
+Lectures by Walter Lewin. They will make you ♥ Physics. Beautiful piece of music, need more ! :)
+Gambrinus Csardas by Monti
It’s called czardas
Hi sir. My name is Mahesh and i am from India i came across a problem while studying rotational mechanics that when we rotate a ring by our finger it rotates in horizontal plane but net torgue about finger is not zero. Who balances the torque of mg.
I do not understand the question - rotating a ring by our finger ??????
@@lecturesbywalterlewin.they9259it's not the ring that we wear in finger it is a circular structure of diameter 8cm in which mass is distributed along circumference. You can check jee adv 2017 ring problem. Thank u
@@lecturesbywalterlewin.they9259actually its not the ring that we wear in finger its a circular structure of diameter about 8cm.
Lectures by Walter Lewin. They will make you ♥ Physics. Really made me ♥ Physics
im iranian i really wannas come to oxford help me if you know how can i come there
professor Walter lewin ,who is your life inspiration....any scientist or any other person ??can u share with us.....?
Sir, there was a video in you tube where one claimed that in his camera he had recorded a sudden appearance of green flash in the night sky for a second (if you type at google the word "green flash in sky" you will get the video). I am not sure if this video is fake or real...but if it is real, will you please explain what is the reason behind such sudden flash?
green flashes do not occur at night time
then, is the video is fake?(sir if you please see with"green flashes in sky at night" in google)
I am unaware of green flashes at nite. But maybe they have been seen. The GREEN FLASH (google it) is associated with sun sets. I have seen it several times in my life.
Will you please explain that how a thunder drum works
don't be lazy - use google
Lectures by Walter Lewin. They will make you ♥ Physics. Thanks
Amazing.. Many kids in the lecture must be physics professors by now.
most of my graduate students are Professors now. Some very famous!
Lectures by Walter Lewin. They will make you ♥ Physics. It's good to know that professor. Your teaching has inspired me a lot. Thank you.
Hello Prof, Lewin. I am Angga, studying in Indonesia. Can you give the physical explaination for the difference betwen betwen musical sounds and noise?
+Gustianggara Putra Someones noise may be someone else's music and vice versa.
+Lectures by Walter Lewin. They will make you ♥ Physics. Thank you for the reply.but it is less helpful to me. what are the characteristics and the definition of noise?
+Gustianggara Putra I suggest you Google "noise".
Those kids must be about my age today
Why did the tuning fork make a sound over the exgraduate's head but not over Lewin's head? or was that sound not the tuning fork but the loudspeaker?
Jorge Luque It was a joke. The sound was made by my assistant with a tone generator.
Lectures by Walter Lewin. They will make you ♥ Physics. Haha, that's a good joke! At the end of the lecture there are some kids "checking if they have a brain" with the tuning fork lol
Jorge Luque ha ha ha ha ha