If this is how maths and physics is taught in schools, we would be having many more scientists and humanity will achieve 10 times more in 30 years compared to last 100years… Hats off to Mahesh sir🙏
@@guydude3320 Ehm, scientists still have to originate in the educational system. So yeah, this level of education would ignite the crave fro knowledge for much more people
Loved the video. Just wanted to point out that the use of the binomial expansion and limiting to first order makes it sound like E=mc^2 is an approximate equation. A more formal derivation shows that it is in fact exact and not an approximation. It appears you needed to use the approximation because you took kinetic energy to be 1/2mv^2 in your derivation. That is only true at low speeds. It is in fact your kinetic energy equation that is the approximation and not E=mc^2. The use of the binomial expansion simply reconciles E=mc^2 with that kinetic energy approximation. Actually, it is a very nice way of showing how 1/2mv^2 come about at low speed. A more formal derivation would use the full relativistic kinetic energy equation (derived from the work principle) and then you end up with E=mc^2 being exact. I hope you don't mind me mentioning it but I didn't want people to come away thinking E=mc^2 is not exact.
Very valuable comment! In fact, this was exactly the impression I had: The famous formula surprisingly only the result of an approximation. Not something one would expect from Einstein. Until I stumbled over your remark. Initial disappoinment eliminated now. Many thanks!
@@Wouter10123 The derivation is straightforward in principle, but nasty in practice. Kinetic energy can be derived using the work-energy principle that says the change in kinetic energy of an object is the work done on it to take it from stationary to some velocity, v. You calculate the work as the integral of force over distance. You integrate Fds. But Force is also the rate of change of momentum, p, so you can integrate (dp/dt)ds instead. This is the same as (ds/dt)dp, which is vdp. Still not nice but using the product rule you can convert this to d(vp)-pdv, and integrate that. That is vp minus the integral of pdv. Relativistic momentum, p, is 'gamma'mv, where 'gamma' is the familiar 1/sqrt(1-(v/c)^2) term of relativity. Substitute that in and the final integral is ugly by doable. The answer is (gamma-1)mc^2. That is relativistic kinetic energy! Not at all familiar is it? However, by doing a binomial expansion of it and dropping the higher terms, you're left with 1/2mv^2 believe it or not! To keep things familiar and intuitive, Mahesh started with 1/2mv^2 so had to apply the same approximation to the left side of his equation (so to speak) to make them consistent. You can see the derivation and discussion in more detail on Wikipedia at en.wikipedia.org/wiki/Kinetic_energy#Derivation_2. Hope that helps.
I was hoping someone would clarify this in the comments. That bit felt a bit disappointing after an otherwise excellent explanation. So thanks for the clarification!
I grew up with the assumption that only a tiny group of elite physicists could understand the math of the Theory of Relativity. But you clearly go through the math so that it's comprehensible even to me (who struggles with very basic calculus). Your intuitive approach really brings the theory alive and makes it something we, like you, can marvel and wonder at, rather than regard it as too complicated and remote. Kudos to Mahesh!! (P. S. I was a librarian in Jerusalem and got to know the head librarian of Hebrew University, where the original manuscripts of the theory, special and general, are kept. She gave me the wonderful privilege of seeing the manuscripts in person. It was a very powerful experience, seeing these documents that fundamentally changed our view of the universe.)
You still need to understand the math in detail to do anything useful with it, but it's good to have at least an intuition of it rather than none at all.
Hey Mac what do you do? Do you work in academia or engineering? Or are you doing "ery basic calculus just for fun?... I'm curious about it, as my own practice of maths was left way back..
You’ve got to be one of the best science communicators on this website, every video I’ve seen of yours is so intuitive and as a biologist I sometimes worry about getting too deep into physics and math but your videos help with the pursuit for knowledge
But the information he communicated is not actually real physics truth. Einstein's theories have been debunked many times already. But the easiest way to find why they are wrong is to read the ebook, Dave Vs Hal 9001. Anyone with any ability to think, can now see that Einstein's theories are nonsense. No math required, just logic and reason.
@@everythingisalllies2141Source:Trust me bro. Dave vs Hal 9001 is a fictional book not an academic book. Also, where on actual earth did you see that Einstein's theories have been debunked. Edit: Ah, just checked your channel and found it's a book written by you. Self promotion.
@@NorthMavericks-ow7jk The lie is that they have been "proved" over and over. But you don.t care if this is true or not. Your mind is set like concrete. The theories have no real proof, not one scrap.
@@everythingisalllies2141The SR theory is rational all over. A perfectly logical model that explains real-world observable phenomena with ease and high precision. It has been validated thousands of times.
@@Grecks75 Nope. Its not rational at all. You have been TOLD that its great, but its just not. It doesn't explain real world anything. It does create opportunities for paradoxes. And its never been validated. Faked experiments and misinterpreted observations are not validation. The fact that you have not figured any of this out, is evidence that you are too trusting of your superiors.
@@mnjammnjamm Not TOTALLY, but RELATIVELY happy... Because he is happy only from (y)our perspective. Reality is not known, though Relativity can be! 😊
Mahesh sir always rocks ❤ You are doing an extremely good job and you have a good will. This will help the lot of learners around the world. Hats off to you sir
If that was any other video going through algebra I would have had to stop watching. The way you explained it so clearly, so logically, keeping it tied to the reality of the original experiment, reminding us what we were trying to solve, reminding which formulas we'd already done. You actaully made it make sense to me, and I genuinely got enjoyment from following it. Thanks buddy. You're an amazing teacher
I may feel sad about many things in my life but I always, strangely, find peace in physics. Big thanks for this beautiful video, I will keep coming back to it 🎉
This is actually, intuitively, very appealing! It is quite fascinating that Einstein should have derived this (and speed of causality mentioned in a pervious videos) purely on eliminating what cannot be and accepting whatever that remains! logic following intuition=genius. Thanks for making this video.
I wonder if we could find more physics through this method but not eliminating other 'impossible'maths. Something about negatives and imaginary numbers comes to mind
You can't even imagine how happy am I about finding your channel. You are educational genius, people like you are moving humanity forward and I sincerely dream I can be someone like you. You are giving people new conceptions about the world we live in, transforming information about it into knowledge about it's laws. Thousands of years people paid money for conversations with people who have looked a little bit further in the ways of understanding this world, but now we can listen you for free and I'm grateful for that. If half of the people, who watched your videos will get new knowledge (not as information,but something they will understand) then you are making tremendous work for all the humanity.
This is my first time on this channel, and I just wanted to share my excitement for the descriptions of the relationships among space, time, momentum, energy, mass, etc., the aesthetic feels genuine and I’m only just starting to understand how some of the relationships work, and I’ve little to no practice beyond algebra. I’m missing some details, but that’s what repeated viewings and further familiarization with the subject matter are for. Your intuition based delivery was a unique way to handle that whole area. Thanks so much!
Lucky students that have you as their teacher. Providing an intuitive understanding of the subject matter for students to take with them as they dive into the details is I am sure invaluable. Well done indeed.
There was a point in time when I was satisfied deriving E=mc^2 only using four-vectors and calculus. Now I know how much of a fool I was back then. This is the most beautiful/intuitive reasoing behind the connection between mass and energy I have ever seen. Thank you so much for putting in all of this effort to make reality make just a little bit more sense for the rest of us.
Bro I am a 25 year old guy. Watching your videos like a 20 year kid and learning my favourite subject with so much detail. You made my heart cry bro. How you are putting up with expenses for such crazy animation and time investment. Start memberships of youtube channel if you need. I would love to support you. You totally deserve it.
That means a lot, Harsh. A few more folks have reached out to support. As long as I can manage at my end, I wouldn't want to take anyone's hard earned money. But, thanks again for the concern. :). And thanks for watching.
I admit that I can barely follow because this is not my profession, but I was always interested in physics and I think it is a shame that most people do not get to know or understand these greatest achievements of humanity and I truly admire your work to teach this extraordinary relevant topics. I like your admitation and fascination for science and gave you a like and a sub. Please keep going! ❤
I was never good at math , science . I'm into accounting. But with this kind of videos on RUclips my interest in science has grown and I'm fascinated by this. I sleep most of the time while the video is playing in the background sometimes. It's kind of calming strangely.
A tenth grader learning feynman lectures, theory of relativity, electromagnetism and Lots of works in the field of science.... I am really very thankful to you sir, Even though I study in 10th grade I learnt from your videos so much things... Thanks for introducing me to a very open and thoughtful world.
I came across your channel just recently and absolutely love it! It would be fantastic if you touched on the topic of time paradoxes, time travel and general relativity! Have a great day!
I never knew that I could derive E=mc^2 without even holding a pen and paper and just by visualizing things looking at a youtube video. Just amazing. Loved it~
@@Mahesh_Shenoyfrankly, I felt the video like casual physics lecture 😆. I'm so sorry to say this 🙏🥲. . . . . . . . Let me watch it again in a free time 😅
Your explanation of the relativistic Doppler shift is spectacular! But a subsidiary point of the video is a bit lacking. When you drive by a stationary sound emitter, you do indeed hear a change in pitch. Your presentation of the doppler effect for sound makes it sound like you wouldn't hear a pitch change.
Thank you! Yes, I noticed that. I wanted to put a small disclaimer at the bottom. But forgot to add that. You are right, there is pitch change in sound as well. But, the pitch change is due to the apparent change in the velocity of sound. Not the wavelength. I think that’s the key point.
@@juliensalemkour5708 It is exactly the same for light as for sound ^ orbs= ^s/ 1+ V/C, 1- V/C. If you say the ^ Observer wavelength, ^s the source of wavelength, V is the relative velocity of the source observer and C is for light you are not worried about the speed of light. One easy way to think about it is with white light or white noise both have every spectrum of frequencies in it. So if you say the source is further away you will observe lower frequencies, if it is closer you will observe a higher frequency and between both of those you can observe the medium frequency. This is part of perceived observation because not everyone will perceive the same thing
Okay, okay. Engineer here, and we all know that engs want to see it happening. Not that we don't trust you Maths and Phys, I guess our brains can't hold to it for so long. SO, with that being said, I gotta say that the way you broke it down worked beautifuly, even to me, who's not really the sharpest tool in the sh.. wait, bad anecdote, sharppening stuff IS with us, engs. I don't know how, nor why, your excitement for the derivation of the especial relativity eq is so freaking contagious! 😂 I love it. Several concepts you spoke about here I only studied in Uni, but as greately put by others here in the comments: If only I was taught in school by excited people like you. I can't deny, IT IS beautiful how all of it connects. Awesome video! I want to watch it again a few times!
I have a question about the final stage of your calculation Mahesh. When you carry out the binomial expansion to finally determine that E=mc^2 you ignore the higher powers of x(v^2/c^2) as the velocity(v) is much smaller than the speed of light(c). Doesn't this mean that E=mc^2 is also an approximation and so would not hold for values of v approaching c?
I was a little worried people might think that when I saw the video. Be in no doubt, E=mc^2 is exact. It is not an approximation. In the video kinetic energy was taken to be 1/2mv^2. THIS is the approximation. Kinetic energy is only 1/2mv^2 at low speeds. What Mahesh was doing was using the binomial expansion to reconcile E=mc^2 with the kinetic energy approximation that we are all familiar with. In fact the binomial expansion is a nice way of showing that kinetic energy becomes 1/2mv^2 at low speed. If you use the full, relativistic kinetic energy (derived using the work principle) then you do not need the binomial expansion and E=mc^2 ends up being exact. I hope that puts your mind at rest.
All observers , regardless of what frame they are in, will agree that the atom has intrinsic mass, m, with energy equivalence given by E=mc^2. The atom may be ascribed kinetic energy in addition to this due to its motion relative to individual observers. Kinetic energy depends on the relative velocity of the atom and therefore different observers will ascribe different amounts of kinetic energy. But they will all agree that the rest-mass energy must be exactly mc^2.
I heard a story once--- There was a dull kid and his father hired many tutors but they eventually left that kid saying he was too dull, finally he found one tutor and the kid started doing well in school.... The problem was never the kid, rather it was the previous tutors who lacked in-depth understanding about the subject. The more you understand a topic, the broader your range and simpler the moves are - you can even get a kid dance to the complex tunes. Thanks....
This is a BRILLIANT exposition. Thank you! Its only when the explanation is this good, so eliminating the pervasive obfuscation in this realm, that we see clearly what a intellectual magician Einstein really was; this entire edifice is a nonsense. The egocentricity at the core of Einstein's physics is stupefying - I don't mean his own personal ego but his fixation on observer-centric, "reference frame" effects that don't exist in reality....or to put in Einsteinian lingo, don't exist in the reference frame of the thing itself. To pick just one example here, the observer simultaneously "seeing" red-shifted and "blue-shifted" radiation from his "balanced momentum" source is a foundational contradiction. Mahesh gets to the heart of Einstein's philosophy at 07'30" with "you don't say it's impossible, instead you ask what needs to happen in order for it to be possible"....and so we get "lateral thinking" run amok, then thought-experiments turned into declarative statements, and ultimately into dogma. How do we replicate Lavoisier's conservation of mass experiments at the atomic level? The E-mc^2 proposition is circular; binding energy is released when matter dissociates but the protons, neutrons & electrons are all conserved! The eV can be defined and usefully converted to kg the same way a mass of gold can be converted to USD but that doesn't mean gold is made out of paper or that the bills in my wallet are made out of metal. We've made Einstein into a God-like figure similar to how the ancients did with Aristotle, in the long term, their 'hit rate' will be similar I suspect.
Lack of use and 50 years time since college physics hinders me, but I found your enthusiasm and explanations delightful. I had long forgotten how to resolve nothing travels faster than the speed of light versus Einstein's energy-mass conversion process being dependent on the speed of light squared.
Sir 11:03 if the wavelength of the sound wave stays put while you are in the rocket, that means you would not experience Doppler effect. Its confusing. And we know Doppler effect is due to relative motion between the listener and the source. So this explanation is contradictory. Please look into it. I will appreciate your response.
If you drive past a stationary ambulance you will not notice any doppler effect. For doppler effect to happen with sound, the source has to be moving relative to the medium (air) so only when you are stationary and the ambulance passes by (assuming still air and no wind). For this kind of question I do recommend chatgpt it is amazing
Greetings from London Mahesh. I am 78 and have just discovered your site yesterday and am blown away .I am pleased you are a fan of Richard Feynman and I too have watched and read just about everything there is by him including his magnificent Surely You Are Joking Mr Feynman which I found to be a life changing book. Please accept it then that my saying you are just like him as a teacher is the greatest compliment I can bestow. The enthusiasm, logic and clarity with which you present each subject is truly unique. I have been looking for understandable explanations of E = mc2 and the unachievabilty of faster than light travel for years. You absolutely nailed them and I feel I understand the details now. I look forward to learning from the rest of your videos but just had to tell you immediately what a joy your videos are. How about tackling the Twin Slit Experiment? Just about all the videos I have watched raise more questions than they answer. Very happy to have found your site. Thank you.
At 09:10 min, you said the RHS mass was before shooting the photon and LHS was before. From what I got, LHS is in rest frame and RHS is moving frame, but both after shooting the photons. Please let me know what I'm missing
If you understand that mass is just confined energy, it's easy to understand why the atom loses mass, it lost some of that confined energy. If you know the mirror box example with photons bouncing inside, if you push the box the photons that bounce push against your hand so the box feels like ir resists (inertia). It the box loses photons, less of them bounce when you push it, so you feel less resistance (inertia), so the box lost mass. Mass is just an emergent property of light speed particles (which have momentum) confined inside a certain space, because they bounce on whatever resists moving the system. Everything moves at the speed of light, what doesn't is just a system of multiple particles, and the system can stay still but it's made of all light speed moving elements internally. Nothing moves slower than light, only emergent objects.
Dude...the craziest thing about this video was learning what Albert learned by himself way back in the day...in just under 30mins...this was amazing...
I really feel like I'll need a bit to get a hang of it. Really nice work sir ngl even a toddler in physics would understand this as you even try to explain the slightest of things. I just want to know that if E/c2= ∆m is an approximation, so it won't be able to work for high velocities right? Like those approaching quite much the speed of light like an electron in a bohr's orbit or can it tolerate that much? Lastly, really thank you for keeping me interested in physics even when on the verge of losing it 'cause of this rat race.
There is no such equation. The equation is E=m, which defines the mass in the zero-momentum frame. You can have ΔE=Δm in the absence of change in the 3-momentum. [note: c=1]
E=mc^2 is not an approximation. Be in no doubt about that. The derivation in the video uses 1/2mv^2 for kinetic energy. THIS is the approximation. It is this equation that only holds at low speeds. The use of the binomial expansion reconciles the derivation with this approximation. If you do the analysis using full relativistic kinetic energy (derived using the work principle) then E=mc^2 is exact. This would make the story a lot more complicated though and I can see why Mahesh didn't go there. The key idea in the video is jumping between frames of reference, assuming physics should behave the same from both points of view, and thinking about what that must imply if the speed of light is the same. That is relativity theory.
@@robwilliams4773 No. The accurate equation is E = 'gamma'mc^2. E = mc^2 only works for low speeds or when things are at rest. As mentioned, it's a first order approximation!
Mate, your videos keep blowing my mind! I know all these concepts, but I've never understood them as well as i did now! You're very talented! So lucky RUclips recommended you!
Another doubt is that, in 9.04 part of the video, when you said the atom must have lost mass after it emitted out light, shouldnt the atom on the right (from the girl in rocket perspective) also lose mass after it emitted light?
Yes, it lost mass. But we observed the mass at two different times, one before it emitted photons, and after it emitted photons. This is why we see a diffrence in mass
You have made Physics for everyone ! Hope every teachers we have come across in our life would have taught us like you ! So , Teaching is an ART an ART of making mankind ! a society , a generation , a country ! Teaching is back bone of a society ... more good teachers like you a society has more progress they can do ! Salute Mahesh Sir !
The equation you're citing is called the Relativistic Dispersion Relation, which is the norm of the 4-momentum,||P||^2=P^ag_{ab}P^b, expressed in component form: m^2=E^e-p^2.
Mahesh, I love your videos! I want to study quantum physics and love your intuitive videos and I am happy to tell you that I share your passion for physics!
I've never been able to understand why the speed of light had anything to do with mass or energy ... let alone why it made sense to square c. This all finally makes sense. Thank you.
I loved it and i strongly recommend this video to anyone who wants to understand energy-mass equivalence intuitively from an elementary point of view assuming that we are interested in negligible velocity massive objects
Please keep these videos coming! These are so helpful in explaining concepts intuitively which is something I always look for and love the content you post! Recently came across this channel and have been hooked!
You are awesome, Mahesh! I've been watching all your videos since I found out about your channel. I love your excitement and your intuitive take on hard topics!
You have a gift of going into detail and can explain in a way that many viewers can relate to. I appreciate that. I also understand that you have a comical and conversational way of presenting. But I cannot help saying that, in invoking great names such as Albert Einstein and Richard Feynman in the dramatic conversations and more importantly in your intonations, they do not come out in quite the respectful way toward the two great geniuses as probably all scientists would do. Even in a dramatic conversation when invoking such towering personalities, the intonation should not sound like you and them are equals. They did everything, and they dedicated their lives to doing so, you are just re-telling their findings in a way many people may find easy to understand. But for this important point, that I could not help pointing out, everything else is good! So, please keep it up!
In other words, the science deities are beyond humanizing, right? We must all bow down in supplication in their presence,yes? Yours is the attitude that has got high energy particle physics & cosmology into the mess they are both in.
You've reignited my passions for physics, I watched a vid on a whim and i've been watching them one by one since, you've captured all the things that makes this topic so interesting and explain it so well! Best physics channel I've seen so far!
Love this.. you've shown that a 9th grade student can understand appreciate and admire this without any crazy equations.. a great showman just shows the trick first for us to enjoy.. and then later goes into the making details.. love it
Took put a paper and pen and wrote the hole thing, i never understood the calculation of dubbeler effect mathematically thank you for that. Totally wirth the subscription ❤
Not only a beautiful explanation of the derivation, but this actually allows us to see why the often heard statement 'mass is converted to energy' is misleading: no 'conversion', no 'alchemy', is required, only the consistent following through of the original postulate - that c is constant for all observers - and the consequences of this for objects and observers in motion. Look at Nature and wonder that such simplicity gives rise to such an amazing universe...
Oh my god. I almost cried. You made me realize how Einstein did. How he connected special relativity, light speed and this incredible equation. I've seen dozen of videos and read multiple lectures, and all them were a galaxy away from making me realize what you just did. I own you a coffee! If you ever come to Quebec city in Canada give me call bro!
Excellent. I'm almost having as much fun as you. Thank you well done. I impressed myself when I realized something before you said it regarding the Doppler effect on light I saw the time dilation was needed then you said it. That was fun. So I'm leaning. Thank you . Looking forward to more.
wow - I have never witnessed someone so excited about things wayyyy beyond my abilities - your are amazing - I love listening to you - even though I have NO idea - thank you
24:30 I feel like we should divide both sides by v^2 and take lim v->0 instead of using not so rigorous and accurate approximation. The answer is the same. If we would take more terms in binomial expansion the answer would be different, i think it is a very nice coincidence that only two first terms of binomial expansion (which only applies to integers) gives corrent answer but it is like taking dx^-2/dx, dividing numetator and denominator by d, "-" next to 2 with "-" in fraction, rerranging and getting 2x.
![The most beautiful equation in math, explained visually [Euler’s Formula]](http://i.ytimg.com/vi/f8CXG7dS-D0/mqdefault.jpg)
If this is how maths and physics is taught in schools, we would be having many more scientists and humanity will achieve 10 times more in 30 years compared to last 100years… Hats off to Mahesh sir🙏
No scientists won’t need this simple explanations I just like how he has made it easier for dumb ppl like me to understand it
Let's face it, we haven't achieved much in the last 100 years. 🙄🙄🙄🙄🙄
@@guydude3320 Correct… thats why I said schools not universities 😊… dum
@@mkpatel981 schools are not there to make smart scientists and succesful people... its to train peoplpe to work a 9-5
@@guydude3320 Ehm, scientists still have to originate in the educational system. So yeah, this level of education would ignite the crave fro knowledge for much more people
Loved the video. Just wanted to point out that the use of the binomial expansion and limiting to first order makes it sound like E=mc^2 is an approximate equation. A more formal derivation shows that it is in fact exact and not an approximation. It appears you needed to use the approximation because you took kinetic energy to be 1/2mv^2 in your derivation. That is only true at low speeds. It is in fact your kinetic energy equation that is the approximation and not E=mc^2. The use of the binomial expansion simply reconciles E=mc^2 with that kinetic energy approximation. Actually, it is a very nice way of showing how 1/2mv^2 come about at low speed. A more formal derivation would use the full relativistic kinetic energy equation (derived from the work principle) and then you end up with E=mc^2 being exact. I hope you don't mind me mentioning it but I didn't want people to come away thinking E=mc^2 is not exact.
Very valuable comment! In fact, this was exactly the impression I had: The famous formula surprisingly only the result of an approximation. Not something one would expect from Einstein. Until I stumbled over your remark. Initial disappoinment eliminated now. Many thanks!
like @stolgos8964 I thank you for this precision
That was exactly my question, thanks. Any pointers on how to derive the relativistic kinetic energy?
@@Wouter10123 The derivation is straightforward in principle, but nasty in practice. Kinetic energy can be derived using the work-energy principle that says the change in kinetic energy of an object is the work done on it to take it from stationary to some velocity, v. You calculate the work as the integral of force over distance. You integrate Fds. But Force is also the rate of change of momentum, p, so you can integrate (dp/dt)ds instead. This is the same as (ds/dt)dp, which is vdp. Still not nice but using the product rule you can convert this to d(vp)-pdv, and integrate that. That is vp minus the integral of pdv. Relativistic momentum, p, is 'gamma'mv, where 'gamma' is the familiar 1/sqrt(1-(v/c)^2) term of relativity. Substitute that in and the final integral is ugly by doable. The answer is (gamma-1)mc^2. That is relativistic kinetic energy! Not at all familiar is it? However, by doing a binomial expansion of it and dropping the higher terms, you're left with 1/2mv^2 believe it or not! To keep things familiar and intuitive, Mahesh started with 1/2mv^2 so had to apply the same approximation to the left side of his equation (so to speak) to make them consistent. You can see the derivation and discussion in more detail on Wikipedia at en.wikipedia.org/wiki/Kinetic_energy#Derivation_2. Hope that helps.
I was hoping someone would clarify this in the comments. That bit felt a bit disappointing after an otherwise excellent explanation. So thanks for the clarification!
I grew up with the assumption that only a tiny group of elite physicists could understand the math of the Theory of Relativity. But you clearly go through the math so that it's comprehensible even to me (who struggles with very basic calculus). Your intuitive approach really brings the theory alive and makes it something we, like you, can marvel and wonder at, rather than regard it as too complicated and remote. Kudos to Mahesh!! (P. S. I was a librarian in Jerusalem and got to know the head librarian of Hebrew University, where the original manuscripts of the theory, special and general, are kept. She gave me the wonderful privilege of seeing the manuscripts in person. It was a very powerful experience, seeing these documents that fundamentally changed our view of the universe.)
You still need to understand the math in detail to do anything useful with it, but it's good to have at least an intuition of it rather than none at all.
Thats some cool stuff to see writing of such a person.
Hey Mac what do you do? Do you work in academia or engineering? Or are you doing "ery basic calculus just for fun?... I'm curious about it, as my own practice of maths was left way back..
I have never seen anyone explaining with this energy and so much interest.
Much appreciated :)
You’ve got to be one of the best science communicators on this website, every video I’ve seen of yours is so intuitive and as a biologist I sometimes worry about getting too deep into physics and math but your videos help with the pursuit for knowledge
This means a lot! :)
But the information he communicated is not actually real physics truth. Einstein's theories have been debunked many times already. But the easiest way to find why they are wrong is to read the ebook, Dave Vs Hal 9001. Anyone with any ability to think, can now see that Einstein's theories are nonsense. No math required, just logic and reason.
@@everythingisalllies2141Source:Trust me bro. Dave vs Hal 9001 is a fictional book not an academic book. Also, where on actual earth did you see that Einstein's theories have been debunked.
Edit: Ah, just checked your channel and found it's a book written by you. Self promotion.
@@everythingisalllies2141 Don lie bro. Einstein's theories have been proved over and over again.
@@NorthMavericks-ow7jk The lie is that they have been "proved" over and over. But you don.t care if this is true or not. Your mind is set like concrete. The theories have no real proof, not one scrap.
You are a fantastic communicator of high-level concepts. I love your enthusiasm!
All his enthusiasm is not able to make this explanation rational. Like all of SR theory, its not rational.
the fact that he smiles and shows excitement about the subject is infectious.
@@everythingisalllies2141The SR theory is rational all over. A perfectly logical model that explains real-world observable phenomena with ease and high precision. It has been validated thousands of times.
@@Grecks75 Nope. Its not rational at all. You have been TOLD that its great, but its just not. It doesn't explain real world anything. It does create opportunities for paradoxes. And its never been validated. Faked experiments and misinterpreted observations are not validation. The fact that you have not figured any of this out, is evidence that you are too trusting of your superiors.
His ability to talk to dead scientists is an unfair advantage
But Einstein seems totally happy with that
😂😂
@@mnjammnjamm Not TOTALLY, but RELATIVELY happy... Because he is happy only from (y)our perspective. Reality is not known, though Relativity can be! 😊
@@talatdhk LOL
@@talatdhk this guy relativates
Mahesh sir always rocks ❤
You are doing an extremely good job and you have a good will. This will help the lot of learners around the world.
Hats off to you sir
Thanks a lot :)
Who wants Mahesh sir to upload more videos like this ? And increase the frequency of uploading videos.
Yes. Will do. Have a list of videos ready already
U can use Doppler effect to increase frequency 😂😂😂
@@sgiri2012 I typed velocity by mistake. (Don't take it serious)
Notifications ON!! Yes
Everyone 😅
If that was any other video going through algebra I would have had to stop watching.
The way you explained it so clearly, so logically, keeping it tied to the reality of the original experiment, reminding us what we were trying to solve, reminding which formulas we'd already done. You actaully made it make sense to me, and I genuinely got enjoyment from following it. Thanks buddy. You're an amazing teacher
I may feel sad about many things in my life but I always, strangely, find peace in physics.
Big thanks for this beautiful video, I will keep coming back to it 🎉
This is actually, intuitively, very appealing! It is quite fascinating that Einstein should have derived this (and speed of causality mentioned in a pervious videos) purely on eliminating what cannot be and accepting whatever that remains! logic following intuition=genius. Thanks for making this video.
Thanks a lot for the feedback. Awesome to hear that.
"eliminating what cannot be and accepting whatever that remains!" Just like Sherlock Holmes!
"When you eliminate the impossible, whatever remains, no matter how strange, must be the truth.
I wonder if we could find more physics through this method but not eliminating other 'impossible'maths. Something about negatives and imaginary numbers comes to mind
Here we learn important topics of physics while having fun.
Keep making more videos like this sir.
Gladly!!
This has to be one of the best physics videos on RUclips
You can't even imagine how happy am I about finding your channel. You are educational genius, people like you are moving humanity forward and I sincerely dream I can be someone like you. You are giving people new conceptions about the world we live in, transforming information about it into knowledge about it's laws. Thousands of years people paid money for conversations with people who have looked a little bit further in the ways of understanding this world, but now we can listen you for free and I'm grateful for that.
If half of the people, who watched your videos will get new knowledge (not as information,but something they will understand) then you are making tremendous work for all the humanity.
This is my first time on this channel, and I just wanted to share my excitement for the descriptions of the relationships among space, time, momentum, energy, mass, etc., the aesthetic feels genuine and I’m only just starting to understand how some of the relationships work, and I’ve little to no practice beyond algebra. I’m missing some details, but that’s what repeated viewings and further familiarization with the subject matter are for. Your intuition based delivery was a unique way to handle that whole area. Thanks so much!
Lucky students that have you as their teacher. Providing an intuitive understanding of the subject matter for students to take with them as they dive into the details is I am sure invaluable. Well done indeed.
There was a point in time when I was satisfied deriving E=mc^2 only using four-vectors and calculus. Now I know how much of a fool I was back then. This is the most beautiful/intuitive reasoing behind the connection between mass and energy I have ever seen. Thank you so much for putting in all of this effort to make reality make just a little bit more sense for the rest of us.
That’s a really wholesome comment. Made the effort that much worthwhile:)
Functional equations are need, www.casanchi.org/fis/dinamicafuncionales01.htm
Bro
I am a 25 year old guy.
Watching your videos like a 20 year kid and learning my favourite subject with so much detail. You made my heart cry bro. How you are putting up with expenses for such crazy animation and time investment. Start memberships of youtube channel if you need. I would love to support you. You totally deserve it.
That means a lot, Harsh. A few more folks have reached out to support. As long as I can manage at my end, I wouldn't want to take anyone's hard earned money. But, thanks again for the concern. :). And thanks for watching.
Your enthusiasm for this subject is contagious 😊
I admit that I can barely follow because this is not my profession, but I was always interested in physics and I think it is a shame that most people do not get to know or understand these greatest achievements of humanity and I truly admire your work to teach this extraordinary relevant topics. I like your admitation and fascination for science and gave you a like and a sub. Please keep going! ❤
I never figured it could be derived through such simple means. Easily understandable even for the physics layman. Thanks for teaching.
Such intuitive explanation. Such infectious energy. Kudos bro. You took simplifying complex physics concept to the next level. Keep up the good work 👍
It's all scam look it up make no sense
My favorite channel in all of RUclips. Great instruction and enthusiasm. Keep it up.
Damn Einstein and Mahesh conversations really go deep
I was never good at math , science . I'm into accounting. But with this kind of videos on RUclips my interest in science has grown and I'm fascinated by this. I sleep most of the time while the video is playing in the background sometimes. It's kind of calming strangely.
A tenth grader learning feynman lectures, theory of relativity, electromagnetism and Lots of works in the field of science.... I am really very thankful to you sir, Even though I study in 10th grade I learnt from your videos so much things... Thanks for introducing me to a very open and thoughtful world.
You are most welcome. It’s awesome that you are interested in these things!
@@Mahesh_Shenoy ✨😇
fantastic! I'm 59 and I've long understood the concepts, but never thought I could understand the underlying math.Now I do, thanks!!!!!
Ihv never seen such simplification of such a complex topic. Absolutely outstanding piece of work you've uploaded sir. 👏👍
I came across your channel just recently and absolutely love it! It would be fantastic if you touched on the topic of time paradoxes, time travel and general relativity! Have a great day!
I never knew that I could derive E=mc^2 without even holding a pen and paper and just by visualizing things looking at a youtube video. Just amazing. Loved it~
High expectations.... The intro looks amazing... Lemme watch...
Let me know!!!
What about now 😂
@@Mahesh_Shenoyfrankly, I felt the video like casual physics lecture 😆. I'm so sorry to say this 🙏🥲.
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Let me watch it again in a free time 😅
@@Mahesh_ShenoyAmazing 🤩
The single most important physics video on youtube. Nothing else come even close. Thank you.
Wow!! Really intuitive ❤
Never understood it this better! Thanks
Wow, awesome to hear that :)
This really shows how smart Einstein actually was!
Thanks for the explanation mate! This was a great video!
Your explanation of the relativistic Doppler shift is spectacular! But a subsidiary point of the video is a bit lacking. When you drive by a stationary sound emitter, you do indeed hear a change in pitch. Your presentation of the doppler effect for sound makes it sound like you wouldn't hear a pitch change.
Thank you! Yes, I noticed that. I wanted to put a small disclaimer at the bottom. But forgot to add that.
You are right, there is pitch change in sound as well. But, the pitch change is due to the apparent change in the velocity of sound. Not the wavelength. I think that’s the key point.
Could explain how the Doppler effect with light does lead to a drastic doubling in frequency versus in sound, only leading to a minor change in pitch
@@juliensalemkour5708 It is exactly the same for light as for sound ^ orbs= ^s/ 1+ V/C, 1- V/C. If you say the ^ Observer wavelength, ^s the source of wavelength, V is the relative velocity of the source observer and C is for light you are not worried about the speed of light. One easy way to think about it is with white light or white noise both have every spectrum of frequencies in it. So if you say the source is further away you will observe lower frequencies, if it is closer you will observe a higher frequency and between both of those you can observe the medium frequency. This is part of perceived observation because not everyone will perceive the same thing
Okay, okay. Engineer here, and we all know that engs want to see it happening. Not that we don't trust you Maths and Phys, I guess our brains can't hold to it for so long. SO, with that being said, I gotta say that the way you broke it down worked beautifuly, even to me, who's not really the sharpest tool in the sh.. wait, bad anecdote, sharppening stuff IS with us, engs.
I don't know how, nor why, your excitement for the derivation of the especial relativity eq is so freaking contagious! 😂 I love it.
Several concepts you spoke about here I only studied in Uni, but as greately put by others here in the comments: If only I was taught in school by excited people like you.
I can't deny, IT IS beautiful how all of it connects.
Awesome video! I want to watch it again a few times!
I have a question about the final stage of your calculation Mahesh.
When you carry out the binomial expansion to finally determine that E=mc^2 you ignore the higher powers of x(v^2/c^2) as the velocity(v) is much smaller than the speed of light(c). Doesn't this mean that E=mc^2 is also an approximation and so would not hold for values of v approaching c?
I was a little worried people might think that when I saw the video. Be in no doubt, E=mc^2 is exact. It is not an approximation. In the video kinetic energy was taken to be 1/2mv^2. THIS is the approximation. Kinetic energy is only 1/2mv^2 at low speeds. What Mahesh was doing was using the binomial expansion to reconcile E=mc^2 with the kinetic energy approximation that we are all familiar with. In fact the binomial expansion is a nice way of showing that kinetic energy becomes 1/2mv^2 at low speed. If you use the full, relativistic kinetic energy (derived using the work principle) then you do not need the binomial expansion and E=mc^2 ends up being exact. I hope that puts your mind at rest.
@@robwilliams4773Thank you very much
@@robwilliams4773 Thank you
@robwilliams4773 Thanks.
I am still a bit confused. Does the atom have different energies when viewed from a rest vs. moving frame?
All observers , regardless of what frame they are in, will agree that the atom has intrinsic mass, m, with energy equivalence given by E=mc^2. The atom may be ascribed kinetic energy in addition to this due to its motion relative to individual observers. Kinetic energy depends on the relative velocity of the atom and therefore different observers will ascribe different amounts of kinetic energy. But they will all agree that the rest-mass energy must be exactly mc^2.
I heard a story once--- There was a dull kid and his father hired many tutors but they eventually left that kid saying he was too dull, finally he found one tutor and the kid started doing well in school....
The problem was never the kid, rather it was the previous tutors who lacked in-depth understanding about the subject. The more you understand a topic, the broader your range and simpler the moves are - you can even get a kid dance to the complex tunes.
Thanks....
Mahesh, please make a video on force upon a charge by a magnetic field. Hope you take any action, you may either make a short.
👍🏻✌️🤜🏽🤛🏼
This is a BRILLIANT exposition. Thank you! Its only when the explanation is this good, so eliminating the pervasive obfuscation in this realm, that we see clearly what a intellectual magician Einstein really was; this entire edifice is a nonsense. The egocentricity at the core of Einstein's physics is stupefying - I don't mean his own personal ego but his fixation on observer-centric, "reference frame" effects that don't exist in reality....or to put in Einsteinian lingo, don't exist in the reference frame of the thing itself. To pick just one example here, the observer simultaneously "seeing" red-shifted and "blue-shifted" radiation from his "balanced momentum" source is a foundational contradiction. Mahesh gets to the heart of Einstein's philosophy at 07'30" with "you don't say it's impossible, instead you ask what needs to happen in order for it to be possible"....and so we get "lateral thinking" run amok, then thought-experiments turned into declarative statements, and ultimately into dogma.
How do we replicate Lavoisier's conservation of mass experiments at the atomic level? The E-mc^2 proposition is circular; binding energy is released when matter dissociates but the protons, neutrons & electrons are all conserved! The eV can be defined and usefully converted to kg the same way a mass of gold can be converted to USD but that doesn't mean gold is made out of paper or that the bills in my wallet are made out of metal.
We've made Einstein into a God-like figure similar to how the ancients did with Aristotle, in the long term, their 'hit rate' will be similar I suspect.
Here before this masterpiece gets viral❤️🔥
🤞
Lack of use and 50 years time since college physics hinders me, but I found your enthusiasm and explanations delightful. I had long forgotten how to resolve nothing travels faster than the speed of light versus Einstein's energy-mass conversion process being dependent on the speed of light squared.
Sir 11:03 if the wavelength of the sound wave stays put while you are in the rocket, that means you would not experience Doppler effect. Its confusing. And we know Doppler effect is due to relative motion between the listener and the source. So this explanation is contradictory. Please look into it. I will appreciate your response.
Yes I also got confused at this point
If you drive past a stationary ambulance you will not notice any doppler effect. For doppler effect to happen with sound, the source has to be moving relative to the medium (air) so only when you are stationary and the ambulance passes by (assuming still air and no wind). For this kind of question I do recommend chatgpt it is amazing
@@Mehdital89 are you sure about that though?
These videos are making me fall in love with physics. All of it makes so much more sense now. Keep it up! :)
Nice 👍👍👍
Greetings from London Mahesh. I am 78 and have just discovered your site yesterday and am blown away .I am pleased you are a fan of Richard Feynman and I too have watched and read just about everything there is by him including his magnificent Surely You Are Joking Mr Feynman which I found to be a life changing book. Please accept it then that my saying you are just like him as a teacher is the greatest compliment I can bestow. The enthusiasm, logic and clarity with which you present each subject is truly unique. I have been looking for understandable explanations of E = mc2 and the unachievabilty of faster than light travel for years. You absolutely nailed them and I feel I understand the details now. I look forward to learning from the rest of your videos but just had to tell you immediately what a joy your videos are. How about tackling the Twin Slit Experiment? Just about all the videos I have watched raise more questions than they answer. Very happy to have found your site. Thank you.
At 09:10 min, you said the RHS mass was before shooting the photon and LHS was before. From what I got, LHS is in rest frame and RHS is moving frame, but both after shooting the photons. Please let me know what I'm missing
Mahesh, i love how you interact with Einstein like you just left his lecture. It helps make this so engaging
Love your videos!
Great to hear that!!
If you understand that mass is just confined energy, it's easy to understand why the atom loses mass, it lost some of that confined energy.
If you know the mirror box example with photons bouncing inside, if you push the box the photons that bounce push against your hand so the box feels like ir resists (inertia). It the box loses photons, less of them bounce when you push it, so you feel less resistance (inertia), so the box lost mass.
Mass is just an emergent property of light speed particles (which have momentum) confined inside a certain space, because they bounce on whatever resists moving the system.
Everything moves at the speed of light, what doesn't is just a system of multiple particles, and the system can stay still but it's made of all light speed moving elements internally. Nothing moves slower than light, only emergent objects.
Pls make a video on the derivation of length contraction
Dude...the craziest thing about this video was learning what Albert learned by himself way back in the day...in just under 30mins...this was amazing...
I really feel like I'll need a bit to get a hang of it. Really nice work sir ngl even a toddler in physics would understand this as you even try to explain the slightest of things.
I just want to know that if E/c2= ∆m is an approximation, so it won't be able to work for high velocities right? Like those approaching quite much the speed of light like an electron in a bohr's orbit or can it tolerate that much?
Lastly, really thank you for keeping me interested in physics even when on the verge of losing it 'cause of this rat race.
That’s super awesome to hear 🙌
@@Mahesh_Shenoy The question 😅
There is no such equation. The equation is E=m, which defines the mass in the zero-momentum frame. You can have ΔE=Δm in the absence of change in the 3-momentum. [note: c=1]
E=mc^2 is not an approximation. Be in no doubt about that. The derivation in the video uses 1/2mv^2 for kinetic energy. THIS is the approximation. It is this equation that only holds at low speeds. The use of the binomial expansion reconciles the derivation with this approximation. If you do the analysis using full relativistic kinetic energy (derived using the work principle) then E=mc^2 is exact. This would make the story a lot more complicated though and I can see why Mahesh didn't go there. The key idea in the video is jumping between frames of reference, assuming physics should behave the same from both points of view, and thinking about what that must imply if the speed of light is the same. That is relativity theory.
@@robwilliams4773 No. The accurate equation is
E = 'gamma'mc^2.
E = mc^2 only works for low speeds or when things are at rest. As mentioned, it's a first order approximation!
i love your channel. i started watching you because i needed to for my e&m class, but you made me actually appreciate the subject. great content.
My man doing god’s work. I haven’t completely watched the video, but I bet it is fine!
Thank youuu
Mate, your videos keep blowing my mind! I know all these concepts, but I've never understood them as well as i did now! You're very talented! So lucky RUclips recommended you!
Another doubt is that, in 9.04 part of the video, when you said the atom must have lost mass after it emitted out light, shouldnt the atom on the right (from the girl in rocket perspective) also lose mass after it emitted light?
Yes, i have the same question
Yes, it lost mass. But we observed the mass at two different times, one before it emitted photons, and after it emitted photons. This is why we see a diffrence in mass
ONE of the best videos I have ever seen! Never will forget
Present sir 🎉
Nicee
You're my favourite RUclipsr I found this year!
Yay!!!🥳
If E=Expresso and M= Milk , C= Coffie, this is the formula of the “Macchiato” 😂
Haha!
Mahesh sir deserves the best teacher award....
You have made Physics for everyone ! Hope every teachers we have come across in our life would have taught us like you ! So , Teaching is an ART an ART of making mankind ! a society , a generation , a country ! Teaching is back bone of a society ... more good teachers like you a society has more progress they can do ! Salute Mahesh Sir !
Can you also do the derivation of the complete mass equivalence equation[(E^2=(mc^2)^2+(pc)^2] intuitively....
This is total energy Et = mc²+ Ec
Ec = kinetic energy
The equation you're citing is called the Relativistic Dispersion Relation, which is the norm of the 4-momentum,||P||^2=P^ag_{ab}P^b, expressed in component form: m^2=E^e-p^2.
Mahesh, I love your videos! I want to study quantum physics and love your intuitive videos and I am happy to tell you that I share your passion for physics!
Light is way cooler😎 when it is wave than it is as particle
🆒
I've never been able to understand why the speed of light had anything to do with mass or energy ... let alone why it made sense to square c.
This all finally makes sense.
Thank you.
My body is ready, but my mind is not. See in a few days
See you soon 🔜
the way the terms cancel out in the end to reveal such a beautiful equation is a work of art
Mahesh, I totally loved your intuitive approach. 😍😍Love from Bangladesh.
I loved it and i strongly recommend this video to anyone who wants to understand energy-mass equivalence intuitively from an elementary point of view assuming that we are interested in negligible velocity massive objects
Please keep these videos coming! These are so helpful in explaining concepts intuitively which is something I always look for and love the content you post! Recently came across this channel and have been hooked!
He explained such a vast and complex topic so easily ... Huge respect sir ❤🫡
You are awesome, Mahesh! I've been watching all your videos since I found out about your channel. I love your excitement and your intuitive take on hard topics!
You have a gift of going into detail and can explain in a way that many viewers can relate to. I appreciate that. I also understand that you have a comical and conversational way of presenting. But I cannot help saying that, in invoking great names such as Albert Einstein and Richard Feynman in the dramatic conversations and more importantly in your intonations, they do not come out in quite the respectful way toward the two great geniuses as probably all scientists would do. Even in a dramatic conversation when invoking such towering personalities, the intonation should not sound like you and them are equals. They did everything, and they dedicated their lives to doing so, you are just re-telling their findings in a way many people may find easy to understand. But for this important point, that I could not help pointing out, everything else is good! So, please keep it up!
In other words, the science deities are beyond humanizing, right? We must all bow down in supplication in their presence,yes? Yours is the attitude that has got high energy particle physics & cosmology into the mess they are both in.
I love how you give an intuitive explanation. Please continue making more videos.
Never have i had a better teacher
I love your enthusiasm, and the fact that you want to explain things intuitively, it really helps!
You have a great gift for teaching 😎 this is quickly becoming one of my favorite channels
You've reignited my passions for physics, I watched a vid on a whim and i've been watching them one by one since, you've captured all the things that makes this topic so interesting and explain it so well!
Best physics channel I've seen so far!
Gem of a video. Way more insight than just what the title says
Love this.. you've shown that a 9th grade student can understand appreciate and admire this without any crazy equations.. a great showman just shows the trick first for us to enjoy.. and then later goes into the making details.. love it
This channel is pure gem
Man, whatever happens in life. Please don't lose your passion for physics. It is precious.💎
Goooosh!! This is sooo elegant! Thank you for sharing this video with us! ❤
Yes, this video lived up to its promise. Each time I watch it it gets better. Genius. Thank you.
Just brilliantly delivered. You have a gift...thanks for sharing it.
Man how I've been looking forward for this video! 😍
I really enjoyed seeing such difficulty ideas expressed so well.
Took put a paper and pen and wrote the hole thing, i never understood the calculation of dubbeler effect mathematically thank you for that. Totally wirth the subscription ❤
Not only a beautiful explanation of the derivation, but this actually allows us to see why the often heard statement 'mass is converted to energy' is misleading: no 'conversion', no 'alchemy', is required, only the consistent following through of the original postulate - that c is constant for all observers - and the consequences of this for objects and observers in motion. Look at Nature and wonder that such simplicity gives rise to such an amazing universe...
Oh my god. I almost cried. You made me realize how Einstein did. How he connected special relativity, light speed and this incredible equation. I've seen dozen of videos and read multiple lectures, and all them were a galaxy away from making me realize what you just did. I own you a coffee! If you ever come to Quebec city in Canada give me call bro!
I've been a successfull lecturer for many years, and i can definitely say - you're fantastic
criminally underrated channel
Why don't they teach like this in school? Amazing mind blowing video. Wrote this comment after watching only half of the video❤
This video is a gem 💎
The missing energy is balanced by the amount of energy required for acceleration.
It’s really straightforward.
Excellent. I'm almost having as much fun as you. Thank you well done. I impressed myself when I realized something before you said it regarding the Doppler effect on light I saw the time dilation was needed then you said it. That was fun. So I'm leaning. Thank you . Looking forward to more.
Powerful stuff 💥
wow - I have never witnessed someone so excited about things wayyyy beyond my abilities - your are amazing - I love listening to you - even though I have NO idea - thank you
24:30
I feel like we should divide both sides by v^2 and take lim v->0 instead of using not so rigorous and accurate approximation. The answer is the same. If we would take more terms in binomial expansion the answer would be different, i think it is a very nice coincidence that only two first terms of binomial expansion (which only applies to integers) gives corrent answer but it is like taking
dx^-2/dx, dividing numetator and denominator by d, "-" next to 2 with "-" in fraction, rerranging and getting 2x.