Watching Professor Lewin's lectures makes me happy. :') Such a beautiful way of teaching.

You deserve some special award for this lecture. Hats off👌👌

I feel being in emotional resonance with your way of teaching.. love and respect 💙

I was really terrified at the end when you touched your forehead after helium demo. what an honest man you could ask someone else to do it thanks for your effort sir

One of the best lectures! (8.01x - Lect 31 - Forced Oscillations, Normal Modes, Resonances, Musical Instruments)!

Professor, when I fill a bottle with water, as the water stream hits the surface it produces a sound. And as the bottle gets filled, the sound (tone) changes along with it. Is it because the length available for the sound waves to travel gets shorter and thus the frequency increases?

Dear Prof. W. Lewin. I wish one of the first lessons on music I was taught would have been this way. Now, long time ago, I find extremely interesting the fundamentals on pitches and harmonics, but what it is way more fascinating: we, musicians, are used to work with that matter, the so called pitches, which are nothing but resonaces. Now for a while I have been writing music and considering the sound experience beyond that pitches, which is naively called 'noise' or 'sound 'saturation' (the latter for those who are for it), that is to say: THE TRAVEL from resonance to resonance that experiences sound. I really appreciate that crystal clear lecture (and the elegant maths beyond, which I studyied when I was young, or younger) and the feeling that I can rely on my intuiton regarding sound nature when it comes to inventing music. Kind regards.

Excellent explanation, by far, the best teacher I have ever seen. Greetings from Argentina!!

25:30 Now I understand why speed of sound at room temperature is equal to 4nL in resonance tube experiment. We had used tuning fork which has two nodes and substituting that in above equation gives speed of sound 4nL. My school teacher failed to explain it to me. But you (in 1999) didn't. Thank you, professor.

You played that song like a pro!! I'm a musician..I would know;)

47:50 😂😂😂 That was amazing!!

@29:00, I saw a magician. Finally comprehended resonance. Thank you very much Sir....

best teacher in the world

You deserve a noble prize for teaching physics ,This was awesome LITERALLY!!!!!

This is my favorite of 801

Bestestttt lecture 👏❤

I'm a student of class 12 from India professor U r super awesome professor I wish your name remains immortal in the world of physics U r my role model professor And I wish to be like u professor This video won my heart thank u professor

Amazing...

does spring mass oscillation produce standing wave does it same goes with coupled oscillator?

Amazing

Very Beautiful Lecture, though one thing left me very intrigued. The wind pipe experiment, where you rotate it. You said that it picked out different Harmonics, higher frequency ones and lower frequency ones, you also said that the harmonic frequency can be found linearly, F1 being 480, so F2 would be 960, F3 1440, and so on. I played the frequency along the guitar (Turning my would be A=440 to as close as 480) and what I found was while it hit 480 and 960 it also hit in between sounds, considering A as 480, your pipe also hit C# and E respectively. I wonder why that would be if the harmonic and frequency are based linearly, what am I missing? ( I have tested it by playing my guitar as you rotated the pipe, which is where I found the C# and E notes). PS: By the way, those (C# and E) are in music referred to Third and Fifth notes in the A major( Diatonic scale), combining the First Third and Fifth notes are what are usually referred to Major Chords. Is this related to how harmonic works? Still trying to figure out how it relates to the linearity of harmonic, as the third and fifth are not linear to any Nth degree with the First.

Sir i am doing same with my glass but doesn't get the sound

Hello super profesor !!!! , so if we kept our hand or any mucle from a fixed piont and we tuned our mucle could we have weightfree excersize maby in astronauts or mabe in people that are abed .

Love you sir g

Dr. Lewin, why do you use helium instead of hydrogen for the last demo?

Sir I'm not quite understand why string vibration being like infinite coupled oscillators..... how about for standing wave of string?

i was listening to the lecture with earphones and the time he said that frequency will be much higher that you will need to close your ear i was like thankyou sir . but can't listen at this moment because my father is sleeping next in the room.but want to watch it at higher volume.

sir you drew graph between amplitude and frequency for three coupled oscillator. in that amplitude for all three natural frequency were drawn different. how is this possible? is damping differ at different natural frequencies or is it due to fact that amplitude of force applied are different and when its kept same amplitude of different natural frequency will become similar?

I love how you describe resonance as the system going BERSERK

It would be great if you came out of retirement and went back to teaching at MIT. 🙏👏

After long practice i find it almost difficult to form standing wave on a general rope(as it goes more circular rotation than transverse displacement), then i just watched your rope it's helical in shape so my question is where to find it? and it's been honor and very grateful of you that you provide us with such great lectures. But now do something more give us links also where to buy these small-small scientific equipment's you use. right now just help me how to make a standing wave easily? and if slinky rope is required where to find it?

is the amplitude during resonance is more or equal than during its natural frequency professor?

Professor, I understand that natural frequency is the frequency of the oscillator in the absence of damping. For example, when there is no damping and swing is kicked, the swing would oscillate at its natural frequency. My question is: Why is that kick of the swing is not included/accounted in the differential equation describing the system?

Professor why is it that I hear the loudest sound from a body when it is at its resonating frequency ? Isn't it that only the amplitude is maximum in its resonating frequency and it is not in its maximum frequency Then how come I hear the loudest sound ?

32:42 my exact face when I watch this lecture 😀

47:50 Donald Duck???

Professor what will be the effective length if Only the first hole is covered at 29:30 ?

The ending was very 🎭🎭🎭 funny.... ......

The title reads like a little poem😊

Professor, I have another question. Are natural frequency and resonant frequency the same? My understanding is resonant frequency is the frequency of the input that results in maximum gain, which need not necessarily be same as natural frequency. ( I guess depends on the terms taken for friction) Here, at 68:40 m.kzfaq.info/get/bejne/oJdxd9t9zpfbiZs.html&mode=NORMAL Professor Wit Buzsa shows that peak value occurs at a slightly lower frequency than the natural frequency. So, I think resonant frequency and natural frequency need not be the same. Am I correct? Appreciate any reply.

Why does professor take Fo(coswt)?why not Fo(sinwt)

I always don’t understand when the system resonants, where does the energy come from? “Small input, large output”. Wouldn’t that violate the conservative of mechanical energy?

9:16

Sir, after hearing the bridge example, I just can't help but imagine a bizarre consequence of resonance, where any object could go berserk when resonance frequency is met by a wind source or anything. How is it managed in daily life sir? Do the objects have good damping? Sorry, if it's a silly doubt sir !!

48:00 An old man nearly suffocates and they just smile and gather up their things :)

Stop Focus on iron man no matter how smart he is in building his own technology far ahead of time,The brain of Walter Lewin had clearly surpassed iron man even though he teaches physics rather than inventing something

How to purchase your book For the Love of Physics I want to read can u help me professor I'm a high school student