This website contains all my 94 course lectures (8.01, 8.02 and 8.03) with improved resolution. They also include all my homework problem sets, my exams and the solutions. Also included are lecture notes and 143 short videos in which I discuss basic problems. ENJOY!

@franketemesi3193

7 жыл бұрын

Lectures by Walter Lewin. They will make you ♥ Physics. Thanks

@abhijithrambo

6 жыл бұрын

❤❤❤❤

@dr.deekhounds5339

5 жыл бұрын

26:27 Then it gets to the brains, if there are any. 🤣🤣🤣🤣

@mohammedsulaimanusman525

4 жыл бұрын

Lectures by Walter Lewin. They will make you ♥ Physics. Thanks

This is the most beautiful presentation ever. For the first time I realize that a standing wave is nothing more than a cosine modulating the amplitude of a sine wave. Amazing. I love you!

@lecturesbywalterlewin.they9259

7 жыл бұрын

:)

@sudhamshreddy2756

3 жыл бұрын

@Za Yn you should mention india not kashmir we need to represent our country not unionterritory

@Electroscope

2 жыл бұрын

@@sudhamshreddy2756 I guess he has deleted his comment

@lukaide6359

2 жыл бұрын

@@sudhamshreddy2756 bro why are you Indians so wierd. Always saying love from India. It’s not that deep

@drkenz0tenma

Жыл бұрын

@@lukaide6359 love you from india🇮🇳🇮🇳🇮🇳

You actually made me fall in love with Physics. You are the Legend, Sir!

Sir you explained standing waves to me! My physics teacher had confused me. Thank you so much!! You are the best physics teacher I will ever see. I KNOW IT

@lecturesbywalterlewin.they9259

7 жыл бұрын

😊

I will never forget you Professor Walter Lewin. You are the only physicist that taught Physics with great care and thoroughness in terms concept. Your demonstration proves extremely valuable that registers in my mind. I thank God for your life, and contribution to teaching physics in a way that makes me appreciate and love Physics. You enlightened me of all the topics that I didn’t really understand the concept well, or sometimes not at all because of lack of faculty by others. You are such a gift in the world of Physics. Thank you Professor 🙏.

The simple mention of the fact that, in the standing wave equation, the spatial and temporal information is not interlinked makes for a great tool for understanding how standing waves aren't being shifted left or right (speaking purely in terms of vertical vs. horizontal displacement). Excellent explanation of the standing wave professor. Thank you!

I honestly have reconsider many times going on in my University in Italy since I had no problem in mathematics but Physics was making me bored, at a point that I was going to Economics and Politics because it were more real to me. Thanks is not enough professor, if you'll come back to Europe one day and make a trip in Venice, I'll be the one unveloping the red carpet all over Venice. My next-to-be AeroSpace Engineering Degree is largely becaming a dream come true thanks to you Professor, you made me interested again in Physics and the applications it has.

This is the first Walter Lewin lecture I have ever seen and this is the best lecture I came across in my entire life. Now I know why you are famous :D Cheers from India! ❤❤❤

@lecturesbywalterlewin.they9259

6 жыл бұрын

:)

"Sound" sounds very very interesting because of YOU, Sir.......

@lecturesbywalterlewin.they9259

7 жыл бұрын

:)

I usually find animation more helpful to understand. But animation are nothing compared to these practical examples. You are a legend :).

Dr. Lewin, I've watched several of your lectures since the start of my first year in my physics major and I just wanted to take the time today to thank you for all your dedication you put into these lectures. Thank you for your amazing teaching and making me love physics.

@lecturesbywalterlewin.they9259

8 жыл бұрын

+Enrique Morell Thanks Enrique for your kind words.

You are an incredible teacher and a wonderful human being. You involved your students in the lecture and gave them a chance to demonstrate their talents to everyone. Very rarely is this the case - most teachers are content showing off their own talents (if even that). I will remember this lesson - to give others the chance to impress me - because you never know what amazing talents people have hidden.

well the last 2 min were really appreciable,he can do anything for physics awesome professor👍👍👍👍

Blessed to witness these lectures, sir! It gives me eternal happiness

sir,i'm a student of class 11. I regularly follow your lecture and your teaching come alive to me. I love u sir as well as Physics. Huge respect and love from BANGLADESH.

Great teaching!. This is the way in which Physics/Math should be taught.

✨learning, performing, playing & even listening to music over1/2 my life & I now know I never really understood music ! Actually I may/ will need watch this again & possibly again😬🤫😁 Thank you Sir! ✨

The best demonstration sir. So glad, that me could travel back in time to see your lectures sitting in my home from India ❤

So far I was wondering how the standing wave phenomenon possible. My mind was a mess. Now it's cristal clear how this bizarre thing happens. Thank you so much professor. I love you so much ♥️♥️♥️

Thanks Professor Lewin you make your lectures very interesting. Thus makes us love physics.

For the first time I have understood x-vt concept. Thanks a ton great sir... love you.

This was like rediscovering musical instruments. Thank you so much.

Many Thank You for the Great job you have done! Probably the only clear explanation (at least for me) of the standing waves that I have come across. Bless you!

@lecturesbywalterlewin.they9259

Жыл бұрын

You're very welcome!

Beautiful, simple and very instructive Demonstration of standing wave with that rope.

It’s been years since ny last Physics class. This vid reminded me how much I love this stuff! Thanks!

@lecturesbywalterlewin.they9259

4 жыл бұрын

You're very welcome!

I love you sir. May you never stop teaching.

Thank You Professor... These lectures are amazing

After i watched this lecture i downloaded a software oscilloscope(for microphone) and a frequency generator and i am testing various frequency's and harmonics to find nodes and i am sliding with my chair slowly away from the speakers to find nodes ..its really fun when i find a node i feel a drop in pressure..its been 2 hours i have been doing this LOL and not bored at all! thankyou prof. lewin

@ayushnema6189

7 жыл бұрын

could you please share the source to download the software? I would really appreciate it. I too am interested in trying it on my piano and having some fun

@ayushnema6189

7 жыл бұрын

Thnx a lot :)

his lectures always recover my passion for physics again after weeks of unintuitive lessons from my physics class

really amazing lecture. I didn't understood these when my physics teacher thought us this . He just wrote bunch of equations that and no one listen to him . Now i am foing all these again and hopeful to find your lecture ( I am preparing for jee so i am reading all thses)

@lecturesbywalterlewin.they9259

2 жыл бұрын

Excellent

Superb dedication Professor. Love from India ❤

beautifully orchestrated by the great Professor Lewin!

@lecturesbywalterlewin.they9259

4 жыл бұрын

Thanks for listening

First of all. These lectures are simply beeaautiful. Thank you for making them aviable for everyone. In the aparatus shown, the fact that the waves are aparently static is due to a recognition of the machine of the frequency of the particular wave?

Anyone else notice that he played Epona's song from The Legend of Zelda Ocarina of Time at 33:50?

@osmelsoto4907

5 жыл бұрын

you think he did that on purpose? XD

@MrJason005

4 жыл бұрын

Probably accidental. I could be wrong though!

Wow! Very wonderful playing of ysaye’s third sonata by the student.

I feel like studying physics . The most beautiful video❤️

This lecture is absolutely beautiful. Thank you sir.

I am so enlightened to watch this lecture video of the Doctor, Walter Lewin.

This teacher can inspire anyone to learn physics. I myself am inspired by him. This is my channel about Science.

Best sir. this kind of visitation not seen and"herd,😀" before I would really really really really like to learn from you

Nothing can be better than this

Thanks for the practical explanation! My teacher didn't explain me exactly what it's physical meaning is...

You are true inspiration..what a extremely well thought lecture...genius,,omg

@lecturesbywalterlewin.they9259

3 жыл бұрын

Wow, thank you

You pick a 4 unique music instruments based by its special point. I interest in the swinging string and the instrument that produce low-tone sound as it is work like ancient music instrument, we use string pundulum and metal another one sound like some kind of shell (hard to find for a perfect voice).

Enjoyed a lot this lecture while learning!❤️

6:00 sir how is wave exactly as 2sin3(x-6t) getting produced even if the source is also moving horizontally?

Wow! With this teacher everyone would want to be a physicist!

Sir , will the amplitude of the standing wave change for different resonance frequencies ?

In reed based woodwinds instruments, e.g. clarinet or saxophone, if one blowconstantly on a note, theb open the register hole which eliminate the fubdamental freq so you get a note in hugher octave but then you close the hole and magically you do not get the low fundamental as long as you continue blowing air in. Only when one stops and dtart again the low fundamental freq appears again. I wonder why?

35:03 third harmonic actually because the interval with the next one is a fourth. And 35:18 is the second harmonic because the interval with the harmonic above it is a fifth.

Sir, you are more than amazing.your presentation made me love physics.❤️❤️❤️❤️❤️❤️❤️

@lecturesbywalterlewin.they9259

2 жыл бұрын

Glad to hear that

@mohammadayasha9499

2 жыл бұрын

@@lecturesbywalterlewin.they9259 feeling so amazing that a great person chatted with me .🥳🥳 Thank you professor.

I like the way you tie the mathematics to physical demonstrations. It is all to easy to to get lost in mathematics and lose sight of the physics.

Beautiful sin function you drew. Those aren't easy to draw.

Sir, I have a question about standing wave, if wave (when it reflects from the wall) changes its phase for 180 degrees shouldnt then the reflected and the coming wave be out of phase and cancel each other

@lecturesbywalterlewin.they9259

6 жыл бұрын

watch my 8.01 and 8.03 lectures on standing waves. cancellation ONLY accurs at the nodes of the standing waves.

Violinist at 43:35 played Ysaye's 3rd sonata.

In case of fundamental frequency, we always get high amplitude as compared to other harmonics so is it safe to say that if we want to have destructive resonance then fundamental frequency is the most suitable option for it?

@lecturesbywalterlewin.they9259

7 жыл бұрын

This will often be true. However, it's in principle possible for objects to break much easier in the second harmonic than in the fundamental. Suppose you took a glass rod of length L which is thinner (thus weaker) near L/4 and 3L/4.. It may then be easier to break it when you excite it in first harmonic above the fundamental than in the fundamental. There may be many objects (including bridges and glass wear) that are more vulnerable at res freq above the fundamental than at the fundamental.

I love you man. you are the teacher who have understood the depth of conceptions. i really learn from your videos and i appreciate you😍😍😍

@lecturesbywalterlewin.they9259

5 жыл бұрын

thanks for your kind words

You are definitely a GENIUS

@lecturesbywalterlewin.they9259

7 жыл бұрын

:)

Love you sir This made my day 😍😍

Sir here why you take moving graph firstly and how you thought that for positive x direction we should take minus t and vice-versa?....

Amazing teaching style

Wonderful- a treasure.

When you showed the graph of the sound waves (the last one) was it a convolution of one wave with the other or am I mistaken?

@lecturesbywalterlewin.they9259

5 жыл бұрын

displacement of the membrane of the mike as a function of time

may I ask what piece of music was tom playing on his violin? at 43:31 it sounds beautiful.

@jcheattai

7 жыл бұрын

Ysaye violin sonata, I'm almost sure that it is n°3

@tecktonikboy13

7 жыл бұрын

nice, thank you very much! :)

Watch this Lecture and listen to Kind of Blue. Preferably at the same time. Thank you, professor!

@lecturesbywalterlewin.they9259

2 жыл бұрын

You are welcome!

Thank you for these amazing classes ❣️😊❣️

@lecturesbywalterlewin.they9259

2 жыл бұрын

You're so welcome!

Beautiful!

After filling lakhs of fees, real knowledge is found on KZread for free.❤️

35:27 how did u estimate the numerical values of frequency in Hz sir? Absolutely mindblowing

Hello, Professor Lewin. My textbook used cosine to represent standing wave instead of sine. So, y1 + y2 = 2ysin(kx)sin(wt). I felt confused. Are they the same? Can you explain it to me?

@lecturesbywalterlewin.they9259

8 жыл бұрын

+JunYu Lei If the string is closed at both sides, then at x=0 and at x=L the displacement must always be zero. As long as your solution meets those conditions it does not matter whether you have sin or cos. If the string is closed at one end but open at x=L, then your solution should give a displacement of 0 at x=0 at all times and dy/dx must be zero at all times. As long as your solution meets those conditions it does not matter whether you have sin or cos.

Awesome lecture!!!

@lecturesbywalterlewin.they9259

2 жыл бұрын

Glad you liked it!

absolutely wonderful

Hello professor.. How are you?I have a doubt. If the magnetic force depends on the velocity of charge and accelerating charges create radiation. Then, in which frame of reference the velocity and acceleration are measured. If I accelerate carrying a charge in hand, it's stationary for me but accelerating for others.. Does it radiate?

Great Lecture Professor!

@lecturesbywalterlewin.they9259

8 жыл бұрын

+Fabrizio Tabasso Thank you!

This is so beautiful. God damnit. Why are you so marvellous! Unbelievable. My hero forever !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

@lecturesbywalterlewin.they9259

7 жыл бұрын

:)

33:48 why does the flute have a whistle type opening at beginning and not just a hole?

sir, in sin(kx-ωt) , if i substitute x=vt , where is the linear velocity of the wave and you said v=ω/k. Then k gets cancelled and i get the remaining ωt. So then ωt - ωt becomes zero. I know this is not correct but pls tell me where am i making mistake. waiting sir..............

@Tikorous

4 жыл бұрын

kx measures the number of radians travelled by a point on the wave to get to a particular x value. wt measures the number of radians travelled by a point on the wave to get to a particular t value. x and t are independent dimensions. By linking them you're tracking a single point not an infinite sine wave. So kx - wt becomes "take the number of radians it took to get to this place in space minus the number of radians it took to get to this place in time" which are obviously always the same.

Came here to learn actual meaning phase. Thanks sir walter

Very good lecture Sir. Thanks and Regards 🙏🙏🙏🙏🙏

@lecturesbywalterlewin.they9259

2 жыл бұрын

Most welcome

Is this a university course? My school taught us at 11grade

professor,what is the energy equation for sound wave????

@lecturesbywalterlewin.they9259

7 жыл бұрын

question ill-defined - use google

Woww. Professor Walter Lewin changed his voice more sweeter than my Girlfriend..❣️

I have a question about the traveling wave equation y=2sin3(x-6t). When I search on the internet I always find that the equatin is y=2sin(wt-kx). When we write equation for AC voltage it's also u(t)=U*sin(wt + "theta" ). So I'm not sure which one is correct. Please forgive me if I am missing something obvious, thank you in advance.

@lecturesbywalterlewin.they9259

8 жыл бұрын

+Nikola Vulinovic TRAVELING WAVES y=2sin3(x-6t) = 2sin(3x-18t). Thus k = 3 (lambda = 2.1m) and omega is 18 rad/sec. y=2sin(wt-kx) => y=-2sin(18t-3x). Again lambda = 2.1 m and omega = 18 rad/sec. The - sign is a phase change of 180 degrees. NO PROBLEM! These are TRAVELING WAVES!

@lecturesbywalterlewin.they9259

8 жыл бұрын

+Lectures by Walter Lewin. They will make you ♥ Physics. u(t)=U*sin(wt + "theta" This is not a traveling wave.

@nikolavulinovic8678

8 жыл бұрын

+Lectures by Walter Lewin. They will make you ♥ Physics. Thank you so much for clearing that up for me and answering so quickly. I see now that I need to study a bit more before asking a question. I would just like to take the opportunity to say that I love your lectures they're so interesting and helpful, Thank you again very much.

Wow I had a doubt about harmonics and standing waves I came here and it got resolved thanks!!

@lecturesbywalterlewin.they9259

5 жыл бұрын

super!!!

@abdulkarimhalai6708

5 жыл бұрын

@@lecturesbywalterlewin.they9259 oh my god you replied so quick!! I love you Walter lewin sir!! Only if I could meet you and talk to you!!!

At 42:38, Sir, how did you convert the sound wave to an electric signal such that it could be observed on a cro.

@lecturesbywalterlewin.they9259

6 жыл бұрын

feed the output of a microphone to an oscilloscope.

umm in the beginning,, so 18 is the omega.. but isn't omega suppose to have pi or at least a degree symbol in it..?? I don't get why the omega can be just an integer without any degree symbol..

@lecturesbywalterlewin.they9259

8 жыл бұрын

+GThinks the unit of omega is radians per sec. thus 1/sec.

I am a professional trombonist. I really enjoyed your presentation. I have a question regarding what I believe to be standing waves. I blow air through my lips, which causes my lips to open and close rapidly. The frequency can change but it gravitates towards the harmonic series related to the length of the trombone at any particular time. If air is being displaced into the instrument, the air would also be displaced back into my body when the lips recoil back to their original position (which means my lips actually move forwards and backwards as opposed to just 'up and down'- the 'open and closed' is a byproduct of 'back and forth'). If there is also air being displaced into my body, then that would mean my body resonates like a drum. If my body resonates like a drum, then the amount of tension my body has will change the amount of resonance it can produce. Does this mean that body tension will change my overall sound (I assume amplitude)? Do you know of any information regarding body tension? I haven't really found any research addressing this type of measurement. Thanks for any help you can provide!

@lecturesbywalterlewin.they9259

8 жыл бұрын

+Jason Sulliman If you produce a 440 Hz tone with your trombone, it's the air inside the trombone that oscillates at 440 Hz and with higher harmonics. The air in your body will not vibrate at 440 Hz.

@JasonSulliman

8 жыл бұрын

+Lectures by Walter Lewin. They will make you ♥ Physics. But how than that be? I understand that the air inside the trombone will oscillate at 440Hz, but given the way the lips are moving air, *some* oscillation of air must happen in the other direction- I assume 440 in this example but at a different amplitude. I am interested in learning more about this phenomenon but no one seems to have done any research on it. I just don't understand how it could *not be a factor. The more relaxed I am, the louder and fuller my sound is. I would go so far as to say larger players have an easier time producing larger sounds (I think) because the mass of their bodies contributes in some way to sound ia standing waves. Am I really way off base? Thanks for getting back to me.

@lecturesbywalterlewin.they9259

8 жыл бұрын

+Jason Sulliman your lips do not produce the 440 Hz. Of course the 440 Hz tome, sound waves produced by your trombone, propagate in all directions. Also in the directions of your ears, lips and arms but the energy in the sound waves that reach your lips, arms and ears is insufficient to act as a driving force to make your lips, arms and ears noticeably vibrate at 440 Hz.

What's the piece's name played by the saxophone ?

i did not understand how the wave was created by a rotating wheel. Won't the string just twine to the wheel?

27:30 Sir do submarines detect underwater mines through this phenomena??

Love you sir .... ☺️

Very impressive!!!

Sir I didn’t understand 5:30. How would a wave be formed

Why is a standing wave forming in the one open - one closed musical instrument?

@lecturesbywalterlewin.they9259

5 жыл бұрын

watch my 8.01 and 8.03 lectures on standing waves

in 16:55 in a standing wave what is the velocity "v" refereed to??

@lecturesbywalterlewin.they9259

5 жыл бұрын

watch my 8.01 lecture on standing waves

Sir, can you please explain how a antenna radiates?

@lecturesbywalterlewin.they9259

7 жыл бұрын

watch my 8.03 lectures and/or use google

Sir, how is velocity of vibration of a string dependent on stress ?

@lecturesbywalterlewin.they9259

6 жыл бұрын

watch my lectures v=sqrt(T/mu)

31:37 that’s some useful information even outside of music and physics ;)

Best presentation professor

@lecturesbywalterlewin.they9259

2 ай бұрын

Glad you think so!

which song did he play on saxophone ?1 if anyone knows please comment