Holy shit this is so relatable to me. I have this feeling of missing out or of not actually knowing something unless i can derive it myself in my mind

I'm the same way. I look up word roots for the very same reason, understanding of context allows for deeper learning.

@@xxxalphaeverythingxxx8489 same. This is annoying at times but it is the way my brain works and I've come to accept it 😂

People who simply memorized equations won't learn anything. It's people who question equations that will grasp the theories.

@@BD-np6bv Couldn't agree more.

Thanks! Plenty more videos on the way

As I am even a little bit older now I do understand why I needed to learn all those rules of math in school! That's more than 50 years ago. As I ended up being a practical electric engineer and not done a theoretical job I catch just a tiny bit of it. I really get that marvelous feeling again of understanding all those math 'tricks' as I had to learn 50 years ago. Keep making these excellent videos!

@@PhysicsExplainedVideos You must be doing something right here. I see I am not the only "old" dude here who once was taught this stuff in a much more complex way.....and subsequently never used it my profession.....only to appreciate what you have done in 30 mins on KZfaq. Rather than "whine about the loss", you inspire me to watch it again and your other videos as well. Bravo to you Sir!

Jeesh.. anyone here under 60? Old UK duffer here, enjoying the ride :)

@@tim40gabby25 it takes a great deal of experience like decades of engineering to truly appreciate and dive into these equations and walk with Einstein discussing physics though for only a short period of time....yes Albert ..now I see where you're coming from....

I know what you mean!

Only one in A Million brains though! 🤔

That is what I have gotten out from this we are so Superior with our brains but only a few of us can comprehend with mathematics. To come up with these equations But not necessarily saying they're smarter than the Average person. Common sense is a whole another thing.so cool though 😎

Not life, my friend. Life is a fundamentally biological concept. This is like looking into the game files of the universe itself.

@Chris Madaj The measure of smartness depends on the smartness frame of reference!

You are easily pleased, John, I find the explanations to be so obfuscated and trite as to be of no use.

@@jasoncassidy492And you sir put a lot of effort to make your comment more obfuscated than it needed to be. If you think this is hard then maybe the oversimplified mildly incorrect explanations of physics are more for you

😊😊😊😊😊😊😊😊😊

I’m now an expert

​@@nerdsunscripted624 Nothing hard about it, time does not exist and energy has no relation to mass, therefore E= mc^2 is nonsense. F = ma makes perfect sense since a force applied to a mass can cause it to accelerate. However, E = mc^2 suggests energy can be converted to mass and vice-versa. We have no idea what energy is and we define it loosely as the ability to do work. When Einstein created that equation, he was talking about electromagnetic energy being converted to mass. He believed that and he was wrong. Can it also be applied to thermal, electrical, mechanical, and gravitational energy? Don't think so. Einstein lived in a time when these phenomena were just starting to be investigated. I fear he jumped to irrational conclusions.

Thank you so much!

I’m just in the 2nd of 3 years in high school (in Sweden) so it’s not that advanced but my physics teacher is amazing at teaching both. He shows how somethings works and then how to get the equation for it, often using previously learned equations

It very much depends on who your professor is. Physics is one of the most amazing and Fulfilling sciences and subjects in school today. ( my opinion )

Totally and completely true. The simplicity of expression is a wonderment.

@@am3rgam3r I read the old books by the people of that made the theorems. I find their instructions to be often the best.

Very glad to hear it, thanks for the comment and feedback

@@PhysicsExplainedVideos Obviously you are doing something right. Don't stop.

I feel the same way exactly after having been an electronics engineer for 40 years I have gone through the same revelation as you have....more power to him...the best I have ever known...

Yes. As an interested layman, I found this helped to take me round difficult corners better than some treatises I read in the past

@@alirezanabavian771 Ditto

I got one for you. E=ymc² where y is the Lorentz factor. Time is 1 dimentional. And spacetime stretches to accommodate the necessary interactions with the Higgs field to maintain mass.

Now that you don't feel stupid, consider this: 9:40 "we'll see the light take a zig zag path": I go off the rails right here. Imagine the train going around me in a circle at 300m/s and 1km away. I'm watching a tennis player riding in a glass boxcar hitting the ball against the wall repeatedly (i.e. your tic tok). I am standing on a rotating disk looking through a telescope such that my view is perpetually perpendicular to the train's velocity. I don't see any zig zag. I don't see any dilation. There is no warping of space or time. Further, if there is a glass box car on my disk with a tennis player doing the same thing as the disk rotates, and I have a split mirror allowing me to observe both simultaneously, their "tic toks" are in perfect sync. Now speed up the train to any velocity you like...say 300e6 m/s. And speed up my disk rotation accordingly. I still don't see any zig zag...yet I am stationary and the train is moving at the speed of light. Further, the tennis players continue to hit the ball (as observed by me) with no zig zag and in perfect "tic tok" sync. And they both have the same mass. The tennis player on the train doesn't enlarge to infinite mass...and if you like, extend the radius of the circle such that he doesn't get squashed by the centrifugal force...and I don't get dizzy with the spinning. There is no magic at the speed of light...or anything to suggest I can't exceed it. Further, a train running the opposite direction but same speed on parallel tracks would appear to approach at twice the speed of light...because it is...and we likely should expect a Doppler effect, just as we observe with sound. 25:88 Then you go on through all kinds of math and end up comparing energy. And you have this spurious mc^2 term that you begin to explain away. But let's start that other train in the opposite direction on parallel tracks. Both trains carry a mass of 1kg. They are both traveling at a velocity of v^2. The KE of those masses is 1/2 mv^2 each. Together it is mv^2. Now, when we get to v = c, just as the masses are about to pass each other in opposite directions, push one mass into the path of the other...taking virtually zero energy to do so (e.g. you moved the mass 5 m perpendicular to the v ...or you move both masses 2.5m ...one toward me and one away from me...while they each travel 300e6 meters in the one second it takes me to do the shoving). And bammo! The masses collide and their velocity adds instantly to zero. And their KE goes instantly to zero...and turns into heat as the masses vaporize. By the time they hit, I'm 150e6 meters away and just see the flash. How much heat? Well, it's 1/2mv^2 plus 1/2mv^2 or mv^2. And if v is c, then it's E=mc^2. Now where is the magic? Where in any of this does relativity come into play? And do you really want me to believe that one tennis player is aging more quickly than the other? Or that the tennis player goes to infinite mass? And you really want me to believe there are massless particles? Why? I'll bet Tesla would get it. I'll bet he wouldn't have to make up photons either.

@@toddmarshall7573 sorry, but all of your thought experiment is wrong from the very beginning, because special relativity only applies to INERTIAL FRAMES, and your frame of reference is rotating, thus anything but inertial. In a rotating frame of reference you experience accelerations, thus you would have to consider space-time warping according to the laws of general relativity.

@@enricolucarelli816 something's peculiar. I can find your reply on my phone but not on my computer.

@@enricolucarelli816 Todd Marshall 38 seconds ago @Enrico Lucarelli something's peculiar. I can find your reply on my phone but not on my computer. ...... and now "having replied on my phone" it shows up on my computer...so I can respond. " sorry, but all of your thought experiment is wrong from the very beginning, because special relativity only applies to INERTIAL FRAMES, and your frame of reference is rotating, thus anything but inertial." And I agree with you. The INERTIAL FRAME is physical...a body in motion tends to stay in motion...and its direction is constant unless acted on by another force...that's inertia. That being said and understood by both of us, and trains A and B moving in the same INERTIAL LINE, which of the following assertions are correct and which are false: (1) The speed of light is constant and the same for all observers. (2) The wavelength(s) of light is (are) constant and the same for all observers. (3) The speed of sound (in its ether of air) is constant and the same for all observers. (4) The wavelength(s) of sound (in its ether of air) is (are) constant and the same for all observers. (5) The length of a ruler is constant and the same for all observers. (6) The "appearance" of a ruler is constant and the same when viewed from all angles. (7) Light from a flash light on a train moving at the speed of light is the same for all observers (8) Two trains moving in the same inertial plane. Train (A) is moving at 80 miles per hour. Train (B) is moving at 80mph plus 150e6 meters per second. On train(B) the wavelength of light from train (A) appears to be twice as long as it really is. (9) In example (8), but train B moving at 90mph plus 300e6 meters per second, the light from train (A) is never observed on train (B) (10) Train (B) cannot move at 90mph plus 300e6 because it's mass grows to infinity at that speed (11) A ruler on Train (B) is a different length than on Train (A) at any speed greater than 80mph. (12) A ruler on Train (B), as observed on (B) is of zero length when moving at 300e6 meters per second (13) A ruler on Train (B), as observed on (B) is of infinite length when moving at 300e6 meters per second (14) A flashlight on Train (B), as observed anywhere has the same mass as on Train (A) My answers: 1-T; 2-F; 3-T; 4-F; 5-T; 6-F; 7-T; 8-T; 9-T; 10-F; 11-F; 12-F; -13-F; 14-T; "In a rotating frame of reference you experience accelerations, thus you would have to consider space-time warping according to the laws of general relativity." More correctly, in a "rotating frame of reference" I experience a force which causes the straight line of inertia to change direction...and that Force is equal to the Mass times Acceleration. That being said and understood by both of us, it suggests "no" change in any of the "rulers" taking measurement...be they space or be they time. And perceptions don't change that.

Thanks!

I am glad you love science, and I can see that you still have a lot of fait in humanity. I believe you are wrong, most people will be asking if it's going to be in the test, and eager to just learn how to calculate, get the grade and forget about it. If you stop to look at it, you will notice that it's not as bad as it seems. I for example, have little interest on following the last fashion, aldo, in a daily basis, it affects us. Even so, if one says "more" people instead of "most" people one will be correct (I am guessing here). Keep your curiosity and your hope, it's a privilege of young age and gives people the power to transform the world, even if it's a little bit, for the better.

@@jaimeduncan6167 I’m 14 too and I agree with you

@@jaimeduncan6167 This is the guy who posted the original comment on another account as I was rewatching the vid and happened to see it. I believe you are correct as I am 16 now and have just finished my GCSEs. A shocking number of people decided to burn their books and notes as soon as we finished which proves your point, I do not really understand the logic behind it but it is just how things are. Fortunately their are still those that learn for curiosity and passion, however few they may be, and so I keep hope that the future can be bright. Thanks for replying and good luck.

@@frankdimeglio8216 you have no idea what you are talking about. Like no idea, there is plethora of experiments that show that you are wrong. Even more, most of the stuff we see and use in a daily basis will not work if you were correct. I am not saying that the current scientific understanding, that predicts stuff with 10 digits of precision is perfect, we know with certainty that the current models are incomplete but dude you are way off. You really need to study a lot more and be humble. Once you do that your creativity may push you in the right direction.

Same. First time I saw this I was a year 4 med student, did not understand the chain rule. But, after graduating and working, I reapplied for physics and did more math, now I can follow along and it's even better

Jacob...time to put on the thinking cap and re-evaluate. It took me years after studying electrical engineering to understand that time does not exist. I confirmed that with one of my physics profs years later. He replied immediately that humans invented time to keep tract of change. Physicist David Bohm has claimed the same thing, that humans invented time. If we invented time, which we did, basing it on the rotational period of the Earth, how does it dilate? Anyone can convince most people of anything using math, the trick is to explain what the math means. When you look closely at the math in this video, it's all based on a distortion of the human mind and its inability to keep tract of relative motion. It seems astounding to me that Einstein could have missed that mental issue in his analysis.

@@jasoncassidy492 Whether or not time is a strictly invented or a discovered phenomenon, it along with all the other fundamental ideas in physics describe our observations of the universe with unparalleled accuracy. In my current opinion, if a theory like special relativity could so precisely describe reality, then surely its implications must be fundamental to reality itself. Now, I never took an official class in special relativity. Hell! In under 2 months, I'll be starting my freshman year at university. So I have a long way to go with my physics education, and my views have much room to change. However, I hold this particular view very tightly. With regard to your opinion, It seems as though you don't get what time dilation is. To argue that time cannot dilate or be relative because time is based on the rotational period of the Earth is almost nonsensical. The whole point of Einstein's special theory of relativity is that there is no universal clock. Every inertial frame has its own unique metric of time, thereby making changes in time relative between observers. Keep in mind that this principle of relativity is mathematically deduced by the constant nature of the speed of light (as laid out in the video) and this characteristic of light was justified experimentally after Einstein's insights. I think the confusion stems from the terminology of time "dilation". Time doesn't physically dilate; it is simply relative. That's it. Einstein was not perfect, but I bet he was a hell of a lot wiser and more intelligent than 99.9% of the average Joe (like you and me) and even the current physics community. Wow... that was some rant over a comment from so long back.

@@jacobpeyser2169 Jacob....what else could time dilation mean? The basis of Einstein's relativity theory is that both time and length change as a mass approaches the speed of light. He got that idea from Lorentz who had hypothesized earlier that time and distance must change when transforming between two axes moving relative to each other, as velocities approach the speed of light. Louis Essen, who invented the atomic clock, pointed out the error in both views. Both Einstein and Lorentz changed reality to make their equations work. Einstein arbitrarily changed the definition of time, and that is not allowed in science without proof. He supplied no proof, his conclusions are based strictly on thought experiments. He also ignored the fact that we humans defined time based on the Earth's rotation.

🤓😒🎃

l l i’ll lollll l i’ll l l l l l l l l l l l l l l p p p p p p p p p p p p p p p p l p p p p p p p p p p p p p p p p p p p p p i’ll p p p p p p p p p p p p p p p p p p p p p l l p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p l p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p i’ll 😢

Thanks for explanation, helps.

@@iamprox3690 agreed. This guy is bullshitting.

Dave...another David...the physicist David Bohm... once stated that an equation with no reality to back it is garbage. Time has no existence and the use of it as the basis of a theory is beyond garbage. The irony is that so many people blindly accept Einstein's theories simply because of his appeal as an authority figure.

I totally agree!

@@xiaoxiao-kg5np given that the set of um.. Kabbalists does not include Maxwell, then your "all" assertion is false, allowing for your house of cards gently to collapse. Wrong channel old boy, kindly meant :)

@@tim40gabby25 Maxwell was not in my set of kabbalists that "discovered" quackery. You tried to add him in. I also did not include Newton, although he was a bit of a believer in alchemy and such, as were many others of his day. So please keep the kabbalists in their own camp of numerology and pseudoscientific quackery. My house of made of solid rock, standing on rock.

@@xiaoxiao-kg5np You should probably check out Gabor Fekete, and get on his email spam list.

@@xiaoxiao-kg5np add Heisenberg to the nope-list

Great to hear!

Hahahaha, I was thinking that as I was saying it

​@@PhysicsExplainedVideos Keep repeating the lie until becomes the truth. E=MC^2 was originally attributed to Olinto De Pretto, you and your cult of Einstein had destroyed physics. en.wikipedia.org/wiki/Olinto_De_Pretto "Physics explained" my .....

@@Thebigbangisdeadgetoverit man i wish I was able to be so confident while also being so wrong

@@bixmcgoo5355 Idk it does say on the page that Pretto's formula E = mv^2 (v is the equivalent to c by Pretto) precedes Einstein's E = mc^2 by 2 years. Did you see that part? I just think it's interesting, and tbh just not sure what to think about it.

@@ayo9344 oh I didn't say that the guy didn't come up with an equivalent theory (which is honestly great, though it's worth noting that the ether stuff he was trying to prove was horseshit). I guess the issue is the previous responder saying that Pretto was the one to which E=MC^2 was originally attributed, which is simply not true. They came up with two essentially equivalent formulae, and the proper formula was attributed to the one who discovered it. It's very likely that Pretto's work wasn't taken very seriously further down the line because, again, his entire line of questioning was in reference to a fundamentally wrong idea that is "the ether"

No other word in the english language quite describes a bad expression quite like "ghastly", am I right?

Glad you enjoyed it!

Say hello to daddy aang

Absolutely the same. Every time it's fascinating with how little assumptions and clever actions, such elementary principles can be unveilled (although their primary derivation are works of art by some of the most talented scientists out there *and* their true meaning are beyond grasp for most things still)

I was about to say this same shit lmao

This equation, not was Einstein's creation, but of one italian cientist before.

Thanks for the feedback, I really appreciate it. And thanks for spotting the typo!

Glad to hear it!

This is real physics. PBS Space Time is only physics as entertainment for the general public.

@@vedantsridhar8378 totally agree, still interesting to watch.

Glad to hear it, thanks for the feedback

This was really confusing me then I went back and realised yeah it should’ve been a plus

yep, you are right.

Thanks for the kind feedback, I am glad you enjoyed it!

@@PhysicsExplainedVideos It's really wrong.

? from 8:00 to 13:00 a typical junk on "time dilation"+ he (surprisingly) got a right conclusion on the "mass" but there is a more simple derivation: just multiply both sites of space-time "distance formula" by a constant "m".

When you verified for yourself the truth of what you call "E=mc^2" the energy of what were you trying to discover? All sorts of things can be called energy can they not?What exactly were the dtails of the experiment to test the truth of the assertion "E=mc^2"? Just as a matter of interest how did you measure the speed of light to use in the verification for yourself of "E=mc^2"?How many times did you measure the speed of light and was it always the same in both directions? I am of course assuming that you would dream of just believing what you were told like a rather slow childand thus insisted on verifying eveything you were told by experiment known as the scientific or not_religious method; science being be the verification of every supposition by experiment and were you just to accept without questionE=mc^2" that would be religion would it not? So no belief for you who insistn verifying everything for yourself do you not? In your experiment to verify " E=mc^2 the energy of exactly what was the same as its mass multiplied bythe speed of light which was what when you last measured it. In units of what were you measuring the energy of exactly what? When did you verify for yourself that "E=mc^2"? Was it simplicity itself for you to satisfy yourself so that you were sure that " E=mc^2, or was it a complex and elaborate experiment to verify for yourself that "E=mc^2"? Purely as a matter of anodyne academic interest why might the speed of something other than X(specifically light)have any bearing on the energy of X? One has visions of chaps all over the world saying:" I'm not going to tote that barge or lift that bale because light seems rather slow today." Presumably before you can say that the energy of X is its mass multiplied by the speed of invisible rabbits, you would have to devise some method of establish the energy of X *before you multiplied its mass by whatever to see whether or not they were the same. When you were using the scientific method of verification by repeatable experiment, the energy of exactly what was the same as its mass multiplied by the speed of light which you stablished *by experiment* to be what? How exactly*did*you go about discovering for yourself?

​@@vhawk1951klthe proof is in this video. The OP also never said he did it himself. The speed of light can be derived from Maxwell equation and we use them everyday to make the phone from which you wrote this dumbass comment work. Stop being delusional.

Great to hear!

Glad it was helpful!

Wow, thanks!

My pleasure! The idea that mass is an invariant quantity is often not emphasised in relativity lectures

I had same question - all but that point was fairly clear

Yes that part is not clear to me either. Why total energy is not kimetic energy?

This step alone is responsible for ending up with E=mc^2, but he doesn't explain it. It's a critical flaw in this derivation.

Glad it was useful

Thanks!

On my list...

Glad you liked it!

Thanks for the very kind words, much appreciated!

De Broglie is overrated

Honestly a little surprised we didn't see something from Euler.

On the shoulders of Giants we stand!

@@feynmanschwingere_mc2270 We're enemies now

Glad it was helpful!

I've never seen math so beautifully presented in a youtube comment!

I agree with other comments, beautifully laid out math. How do you do superscripsts, subscripts etc in youtube comments?

@@declankruppa8300 TY. Basically copy & paste + patience. When I searched I found they haven't made subscript & superscript symbols for all the letters. So then I hunted unicode for symbols that look similar. Unfortunately I still don't have a complete set: ᐨ⁰¹ ²ᒾ ³ ⁴⁵⁶⁷⁸⁹ ᵃ ᵇᒃ ᶜ ᵈᒄ ᵉ ᶠ ᵍ ʰᑋ ⁱ ʲ ᵏ ˡᑊ ᵐ ⁿᐢ ᵒ ᵖ ʳ ˢ ᵗ ᵘ ᵛ ʷ ˣ ʸ ᶻ ᴬ ᴮ ᒼ ᴰ ᴱ ᴳ ᴴ ᴵ ᴶᒢ ᴷ ᴸ ᴹᔿ ᴺ ᴼ ᴾ ᴿ ᔆ ᵀᐪ ᓑᵁ ⱽᘁ ᵂ ᕽ ᙆ ᵝ ᵞ ᐜ ᵟ ᵋ ᶿ ᶥ ᶹ ᵠ ᵡ ꚞ ᐞ ᑊ ᑉ ⁽ ⁾ ᐨ ᐩᐟᙿ ∙ __________________ ₀ ₁ ₂ ₃ ₄ ₅ ₆ ₇ ₈ ₉ ₊ ₋ ₌ ₍ ₎ ₐเ ⱃⱃⱈ♭ ᆮ˛˓ㆳ ₑ ᵳ ₕ ᵢ ⱼ ₖ ₗ ₘ ₙ ₒ ₚ ᵣ ₛ ₜ ᵤ ᵥ ₓ ᵧ ˻˪ ˪ ᚁ ˕ ᵦ ᵧ ᵨ ᵩ ᵪ ᚂ Underlining is also a bit unsatisfactory: I start with these: ̅ ̅∂̅xᵈ̅ ̲ ̲d ̲u ̲ & then copy & paste & have to fiddle around with it as it's rather unpredictable what the computer is going to do half the time. Some things e.g. e raised to a power are particularly awkward: ₁ z ̅³̅ ᙆ ̎̄ ̷ ₐ e ᚂ₍ₓ₊ᵧ₎ = e ̅ᵃ̅ ̅ ᚂₓ ⱼ ᚂᵧ = e ̅ᵃ̅ ̅ e ̅ᵃ̅ e ʲ ̎̄ ᙆ ₁ ₋ ⱼᚂ Express e ̅ ⁴̅ in the form a + jb

KZfaq couldn't add LATEX or Markdown to KZfaq comments so this madman did it himself

Thanks

Glad it was helpful!

Did you*believe* what you were told in the classes you mention or did you verify it for yourself by experiment or what some call " science" the physics of which particle hat you could identify as such was what? What exactly were the details of the experiment that you conducted to find out for yourself whether or not E=-mc2? the energy of what were you trying to discover by experiment? Have you yourself ever measured what is called " the speed of light" In your experiments to discover for yourself as opposed to believing what you were told , was the speed of light always *exactly* the same each time you measured it, and you measured it how?

Yes, I think I could have gone into a bit more detail there. Would make a good video!

Wow, thank you!

This channel's explanation is much better

and a teeny weeny bit of inspiration!

Ohhh yeah I gotta learn calculus now to understand it.... That explains why it was so hard for me. I'm just a 9th grader and I was wondering how everybody understood it. But yeah that's the barrier, calculus...... My dad has to teach me it.

❤

what is bro doing here

He getting flexed on by other yoo toobers

I'm only a high schooler so I may very well be completely wrong here but here it goes. Since Einstein(and others before him) knew that there is some other form of energy for masses just as rest by the virtue of their mass, it's a fair assumption to theorize mc^2 as being that additional form of energy. Besides, it was experimentally proven in nuclear fission experiments later on. So my answer to your question would be that since physics drives on assumptions about the natural world, Einstein just assumed it to be true. Again I may be totally wrong.

@@lakshaygupta9061 At least he could not find any other explanation!

Let A = gamma m c^2 Let B = mc^2 If KE = A - B Then A = KE + B > KE So it is reasonable to label A the ‘total’ energy because it is comprised of both the kinetic AND the rest mass energy.

@@PhysicsExplainedVideos ... ,under the assumption that mc^2 is indeed the rest mass energy. Because - if it isn't - it could be the case that we're just *labeling* KE +something as the total Energy. It still seems arbitrary to me. Of course, there must be a flaw in my logic here, but I don't see it at the moment.

@@olli343 KE + mc^2 = E is true, because the fact that KE = γmc^2 - mc^2 holds is true even for free particles. For free particles, PE = 0, and since E = KE + PE by definition, it follows that E = γmc^2.

Thank you very much!