The Electromagnetic field, how Electric and Magnetic forces arise
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- čas přidán 26. 04. 2024
- What is an electric charge? Or a magnetic pole? How does electromagnetic induction work? All these answers in 14 minutes!
0:00 - The Electric charge
3:06 - The Electric field
4:51 - The Magnetic force
7:45 - The Magnetic field
11:00 - The Electromagnetic field, Maxwell's equations
This video is narrated by Octave Masson.
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Alessandro Roussel,
For more info: www.alessandroroussel.com/en
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To learn more :
en.wikipedia.org/wiki/Electro... - Věda a technologie
I hope you like the video! A few clarifications:
- This video was originally created in 2018, before I studied theoretical physics, which is why the content might not be as precise as the other more recent videos.
- Many people are asking how the "playing catch" analogy can explain attraction forces. This is indeed the limit of the analogy. At the quantum scale, virtual particles are really just waves that are spread throughout all space. Therefore they can carry a momentum in any direction, which can have the effect of attracting or repelling particles.
- In the stationary wire, many people are asking why the electrons are not contracted since they are moving. They indeed are contracted, but we consider that they were carefully spaced such that, when contracted, the wire has no electric charge.
- At the end of the video, electromagnetic waves propagate at the speed of "real photons", and not "virtual photons"
Oh Thanks a lot for these clarifications! I just got this video in my recommendation. Glad to see it :)
Hi, I'd like to ask you to clarify even better the stationary wire problem. You say that electrons are contracted in such a way that the electric charge is zero when electrons are moving, but claiming so it should imply that when they are not moving they should be even more spaced out (less contracted), which means that the wire has less electron density than proton density in this case. How can the electron density be always the same (resulting in a no electric charged wire) if there is contraction when electrons are moving and no contraction when they're not moving?
For those, who have a question which I had "how did these electrons become 'spaced' just by applying current?", there is a good analogy: car traffic becomes more spaced after traffic lights turn green, because the first car started moving earlier than the second one, the second one earlier than the third one and so on. Just like cars, some electrons are affected by the electric force that creates current earlier than the other ones, since electric force is not immediate and propagates from some point (or multiple points) with the speed of light.
And just as I wrote that, another question arose: where do electrons find this 'extra space' if they didn't have it initially? Unlike cars, there is no 'first electron' with empty space in front. Also, electrons on the 'forward front' of electric field propagation start moving earlier than ones in front of them, creating an even denser volume of elecrons which can also play the role just after the current started. I'm confused(
thanks for clarifications, for the atractive forces I was thinking if they were sharing somehow virtual photons with negative mass/momentum hahahaha.
I get the part about the virtual photons repelling electrons, but you didn't make an analogous model for the virtual photons to cause electrons and protons to attract.
What causes this attraction?
Every time I asked my professors at college why exactly the electric force (the movement of electrons) produces a magnetic force, none bothered at all to tell me anything and always told me to just accept it. This video finally made me understand how magnetism arises.
I am eternally grateful for these videos that come from the best channel on CZcams. This is pure educational quality.
the real question is why does the magnetic force equation look like the Coriolis force equation?
The fact that it requires Relativity (even if the simplified case of Special Relativity, GR doesn't mix well with QM yet) probably spooked your teachers. Most people, even educated ones, have serious trouble with Relativity, more so at mixing it with Quantum Mechanics, which at the core remains an unsolved problem. Maxwell himself necessarily did not understand the "how" it happens (he inspired Einstein and not the other way around) but only the "what" happens.
@@LuisAldamiz *Special* relativity has been fully integrated with quantim mechanics, it's called Quantum Field Theory. It's only general relativity (the one about gravity) that is problematic with QM.
Fun fact, it was Feynman who was the 1st to describe this phenomena using SR
@@Ecl1psed276 exactly. Dirac combined SP and Quantum Mechanics.
The best science channel
Agreed it's in a nutshell on steroids!
Indeed
It's not even close
Hands down
But worst video in their catalogue
We've come across the "moving current in a wire" explanation to unifying electric and magnetic fields frequently in textbooks, web pages, forums, etc., and yet nowhere was it presented as simply or intuitively as it was here. Blew us away. Really fantastic job!
good to see you here. Love your channel too
Thanks a lot!
Wow, this is exactly the stuff I couldn't wrap my head around until now. Thanks so much for this!
Very glad you liked the explanation! Thank you very much for your support!
Thank you so much for making me finally understand the basic relationship between the electric and magnetic component of the electromagnetic force - brilliantly illustrated!
I can't stress enough, how impactful your videos are. Literally have goosebumps while watching every upload. Thank you so much for what you are doing. By far - and I mean BY FAR - the best educational content of this genre on this platform!
suhlas :)
Shadilay
KKK
How does this not have more views?? Literally the best video on electromagnetism I've EVER seen.
This is high key the best and most concise complete explanation of electromagnetism I've encountered. I also love that you completely avoided equations of any sort, and just went with a qualitative approach, which makes this video very approachable for anyone. Such a clean video and well-made video!
yeah, fully concur, until you understand the mechanics , any equation won´t make sense
@@absolute___zero Well said brother. Just mugging up formulae without proper Intuition and Visualization is not true learning.
I'm an electrician, and theory (D/C Theory, then A/C Theory 1, followed by A/C Theory 2), was part of the required education & class work as an apprentice. Even though I did well in the classes and have a strong understanding of the subject matter, this video (like all your other vids), is so good at explaining complex concepts in a simple and intuitive way, that I now have a broader, deeper, and better understanding of it. Your videos are definitely the best science vids on here. Well done! (And thank you!)
@B.L.A. “those of us with formal education” 🤓
@@kevinflaherty1 so what? You’re jealous of people who pass such high classes that you decide to use the elementary school method of calling them a nerd?
When someone calls you a nerd, they just can’t accept that you may be more intelligent than them. So they find ways to insult you and get more attention for themselves
@@kevinflaherty1
cry harder ignoramus :)
Modern science isn't correct.....
All energy and matter in one simple explanation.... here goes...
First we have a radio wave all the way to gamma waves which in turn create hydrogen then from there everything is basically a compound of hydrogen and will decay back to hydrogen before turning back to gamma waves.....
There are no free moving electrons within matter....
I use this analogy to simplify it in my mind..... imagine a line of people standing a mile long (each person represents a copper atom in a wire) the first person starts a Mexican wave at one end ( the source ) , as the information propagates along the line ( by exciting each atoms magnetic field ) you would see an continuous wave of the peoples arms transferring the charge/information back and forth but the atoms and electrons don't actually move at all.....
Think about it, from the source where electricity is "generated" to the ultimate end use, there's various breaks in chain of that electricity, it goes through controllers, transformers, all sort of components.... the transmission happens because of the magnetic field strength of the atoms in the wire being increased and decreased, not because of an actual "electron" flowing anywhere....
Your videos are among my favorite scientific videos on YT. Every time i see a new upload i immediately cannot help but watch! Thank you for the informative and digestible content!
Same
same
very much the same. He seem to cover conventionel topics, but from a new angle, which somehow also makes it easier to understand
this video is just brilliant. i can't stress enough how much i prefer this way of information delivery than some kind of veritasium. and it's not like the videos lack in something. they are just so much more to the point and stand out due to the enormous effort to explain difficult topics in a simple and intuitive way. this channel deserves much more attention.
They both use different approach and they also complement each other.
Veritasium use more day to day exemple as scienceclic is more text book style
Both style have it's audience.
Also electroboom and veritasium would be furious that it does show the electron moving in the wire 🤣
@@KevenGelinas
[I think Electroboom is smarter than that]
Electrons _do_ move in the wire, but in a sort random brownian-like motion, albeit with a net drift. If that were not the case, it would be impossible to charge a capacitor, and for it to keep its charge on isolation. I'm sorry, but I stopped watching Derek after the quality of his exposition suffered inversely with his growing talent for attracting web-traffic and calculated controversy:
"I'm afraid people misunderstood my video on X." (Then other youtube expositors praise Veritassium's revised X version out-of-beta-test..., generating more traffic).
Derek could squeeze a glass of juice from a desiccated orange.
im not a big fan of veritasium lol. I love a good visually animated example narrated by a calm voice. That way your attention isn't interrupted by looking at someones face haha. (Theorganicchemistrytutor, threeblue1brown, khan academy, in a nutshell,..)
People need to understand that these descriptions are models. Models that can be worked with because they are mathematically correct. But nobody knows what these interactions really look like in reality.
But all the more impressive I find this channel and the author, who really manages to present the phenomena of physics vividly.
I learned years ago: "If someone can't explain something to you easily, then he hasn't understood it himself".
they look like the math says they look like
@@DrDeuteron Then what in the hell is a virtual photon ???
A photon that both repels and attracts ?
Why would two same charges make possible fror them to appear ???
Also when you say something exists for such a short time it actually DOESN'T exist I'd say you got some nonsense on your hands .
@@alokinzna that's a good question. So in Quantum Electrodynamic (QED), one considers scattering amplitudes. E.g: Moeller scattering (e-e- --> e-e-) or Bhabha scattering (e-e+ --> e-e+), which differ by repulsion vs. attraction.
In QED, the Feynman path integral says the EM/electron field takes all possible configuration between initial an final states...which is not solvable exactly.
Instead, on considers "perturbation theory", and you approximate the exact solution with a power series in powers of the fine structure constant (alpha). The first term (called "tree level") has a configuration that is the exchange of a so-called virtual photon.
That is what a virtual photon is. A term in a power series expansion of QED amplitude.
At this level, repulsion or attraction isn't really a thing. If you look up Moeller and Bhabha scattering on wikepdia, they work out the amplitudes in QED, and you will see they depend on (iq)^2 with q = -e or q = +e as needed, and then to get a probability you square the magnitude of the complex amplitude, so the sign just disappears....nevertheless it works.
Moreover, in Feynman diagrams, energy and momentum are conserved at all points in the diagram, so the virtual photon can have very unusual kinematics.
For instance, for two electron scattering back-to-back in head on collision, the photon has zero energy buy large momentum. That means the mass squared in negative. weird for a photon.
Meanwhile in electron positron annihilation in the same kinematics, the photon as huge energy and zero momentum...so it is at rest. Weird for a photon.
Basically: the virtual photon can have negative, positive, or zero energy or momentum...so it repels if it needs to repel, and attracts if it needs to attract.
So with that, virtual photons are just mathematical things that approximate quantum field configurations.
It sounds like BS, but when you use them to calculate "the electron g-factor", experiment and theory agree to 13 (or 14) digits...which is the most accurate and precise calculation in ALL of science. It represents decades of theoretical and experimental work by hundreds (or more) people, and it is remarkable.
@@DrDeuteron You know this is sorta strange .
When talking about gravity you can at least come across the terms Higgs field or Higgs boson .
How is it that getting the details of magnetism is this difficult and obscure ?
Is this a case where we have the detailed description in the form of math as to what is happening but don't know REALLY what is happening ?
Interesting that you _started_ with the virtual photon picture and then introduced fields as a way to think about these interactions.
Usually we start with the fields and introduce virtual particles as a way to visualize the interactions of the fields.
And that's why I never actually understood how it worked until now (well, I'm not sudenly an expert now). Other explanations take fields as a given and just try to expand on them.
what do you mean field? Because if you mean Quantum Fields (Which the Electromagnetic and Electron Field are) then yes virtual particles are just visualizations of the interactions of the field.
When we learn of macroscopic things feeling electric forces, the electric field is seen as a bookkeeping device:
They are the answer to the question "how much force is felt here?, regardless of the charge of a particle to feel it, which may or may not even exist here"
Similarly, we can think of elementary particles, as tangible things that move around in understandable ways.
When two electrons toss photons to each other, they create a recoil "force". Neat!
Again, we build an electric field as a bookkeeping device. Maybe even a quantum electric field.
That is a nice intuitive way to understand what is happening. But if I understand it correctly, physicists believe that the fields are more real than the particles, which are the bookkeeping devices. Because that belief fits better with what we know about reality.
That might explain it:
we want to be thaught in particles, because particles make sense to us,
...but we are thaught in fields by people who see the fields as real, and thus want to explain how the easy-to-understand particles come from them.
We stuggle with the shift in perspective.
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I do not fully understand why fields must be real and not the particles. All below can be wrong and all sorts of ways. But here is what I understand of it:
Macroscopic: The electric and magnetic fields can have ripples in them, that travel at the speed of light. This "light" can exist even without charges around at all. So it seems the fields aren't just bookkeeping the effect of charged things that exert force.
The circuit of unknownsource-veritasium shows that you don't need charged particles to push on each other through a circuit. The effect of flipping a switch would have to take a light-year long detour to reach a lamp only one meter away, taking a year. But instead, the electromagnetic fields that live everywhere carry the signal to the lamp across the gap in the wire. Long before the edge of the circuit knows that something has changed.
In general, I believe there are effects that an electrical circuit cannot predict, because the circuit exists in space, with the wires being close to each other and all that.
Quantum: Virtual particles are weird particles. Two electrons tossing photons back and forth is fine, but the analogy breaks for an electron and a proton. When a proton catches a photon from an electron, it recoils towards the electron instead of away, and vice versa, and that is just weird. The relation between energy and lifetime comes from this: the virtual photon has to fly under the radar of heisenbergs uncertainty relation, which is a limit on what we can detect with accuracy and certainty. But why should it fly under the radar? Can't we sometimes see measurable photons being tossed back and forth, in a proper scientific experiment? I believe that charged particles don't glow, unless sped up or down.
It is said that virtual photons aren't real photons. They are ripples, perturbations, in the quantum electromagnetic field. When those ripples exceed heisenbergs uncertainty relation, they are seen by detectors. And can thus be called "real" photons. Any other feature -- rippleshaped or not -- can be broken in a sum of smaller ripples, which we can argue are still photons -- ripples --, but they travel under the radar. This helps to calculate what the fields do in an interaction, by looking at scenarios of virtual particles doing what particles do. In theory, we need to mix all scenarios by likelyhood, to know what happens. In practice, we mix only the more likely scenarios as an approximation. Either way: the virtual particle is now the bookkeeping device, and the field is the real thing.
@@nielskorpel8860 you cannot detect them because they are pure nonsense. Photon exchanged between proton and electron has negative momentum for proton and positive momentum for electron.
Another problem is - why does any field even exist? If it were for virtual particles to exist, you could imagine how in uniform electric field one pair of electron-positon popping out of nothingness, creating a circle, and then disappear. Not a big problem, but inside said circle, electric forces of the field are balanced out by formentioned particles. You create a "bubble" with no force at all. Now go on with as many bubbles you like, and whole field disappears!
It's absurd, because there is no virtual photon or electron, but quantum field. And all the sudden it all makes sense.
@@Etrexum Actually, that's a far more accurate picture. The virtual particles are just oscilation in the underlying field. Oscilation caused by the real electron themselves. Nothing more.
The single cleanest explanation of this phenomenon I've ever seen. Makes sense without the vector calc but can be used to introduce it. This will now be the way I proceed when teaching E&M.
I teach for a living and this is one of the best short, non technical explanations I have seen. I loved how you picked up the story with virtual photons and also explained the relativistic origin of the effect on the moving charge. One question though! @5.29: the electrons in the wire are moving while the apple is stationary. Why isn't there a relativistic contraction effect there? Shouldn't we expect the moving electrons to appear "more dense" to the apple as they pass by, thus the apple experiences a force? This is the same basic argument which is used later in the video (moving apple, "slow" electrons, "faster" protons).
if the apple is perceived as still, the direction of motion of the wire is leftwards.
The protons move leftwards in the direction of motion because the wire is moving leftwards. These similar motions add onto each other out and net leftward motion is greater. Therefore, wrt. to the stationary apple, protons move faster. Increased speed wrt to the stationary apple is what causes the contraction, as per special relativity.
In contrast, the electrons move rightwards, opposite to the direction of motion because the wire is moving leftwards. These contrasting motions try to cancel each other out and net rightward motion is smaller. Therefore, wrt. to the stationary apple, electrons move slower. Decrease in speed wrt to stationary apple is what causes the expansion, as per special relativity.
You can compare the change in resultant speed of both particles @6:57. Hope this helps!!
@@chad7928 I actually meant the case where both wire+apple are stationary! So, protons stationary wrt apple. So from the point of view of the apple, stationary protons and moving electrons should make the electrons appear "denser" in the wire relative to the protons, no?
I'm not tired to repeat this every time. This is the best channel ever created on youtube. Absolutely brilliant!
What I love about this channel is that it's able to explain physical phenomena in a digestible way without sacrificing the accuracy of the science.
Something main professors should learn from
I never clicked so fast in a notification
This is btw, and I mean literally, the B E S T visualization and explanation for both the electric field, but also for how virtual particles are supposed to carry force, simply amazing, bravo!
Thank you so much, glad you liked it!
Amazing video. I understood how the virtual photon picture, with the recoil, can explain a repulsive force.
But I find it hard to understand how the virtual photon explanation applies to an attractive force between opposite charges.
By the time the video speaks about attraction between opposite charges, the virtual photon picture no longer makes an appearance.
@@elpak it looked like the attraction was depicted by two virtual photons being emitted simultaneously by the electron and proton, and then meeting in the middle. But yeah no intuitive explanation was given for the electromagnetic attraction as it relates to that illustration.
@@ScienceClicEN Modern science isn't correct.....
All energy and matter in one simple explanation.... here goes...
First we have a radio wave all the way to gamma waves which in turn create hydrogen then from there everything is basically a compound of hydrogen and will decay back to hydrogen before turning back to gamma waves.....
There are no free moving electrons within matter....
I use this analogy to simplify it in my mind..... imagine a line of people standing a mile long (each person represents a copper atom in a wire) the first person starts a Mexican wave at one end ( the source ) , as the information propagates along the line ( by exciting each atoms magnetic field ) you would see an continuous wave of the peoples arms transferring the charge/information back and forth but the atoms and electrons don't actually move at all.....
Think about it, from the source where electricity is "generated" to the ultimate end use, there's various breaks in chain of that electricity, it goes through controllers, transformers, all sort of components.... the transmission happens because of the magnetic field strength of the atoms in the wire being increased and decreased, not because of an actual "electron" flowing anywhere....
This channel takes these amazing complex ideas and without dumbing it down simplify it in digestible ways. Thanks for all the hard work y’all
Your one of the most underrated channels on this app, the clarity of the information you explain is unbelievable. Keep it up!
You deserve more recognition your videos and their visuals are easily one of the best scientific and educational channels on yt
Glad to see a new video. I really appreciate them, worth the long waiting time! 🙌
Very glad you like them!
This channel offers some of the best physics explanations I've ever heard and they're so so underrated. When is say underrated I really mean it. How can this channel not have millions of subscribers yet? Damn.
When a free CZcams video explains better than paid University and tuition cources
Great as always. Man, a few years ago I posted on a few science forums trying to understand what magnetic fields actually are. This video underlines that the responders had no idea what they were talking about, but they were extremely confident nonetheless. It was frustrating, and it's refreshing to get this with so much clarity. You have a knack for clear thinking about fundamentals.
I always am looking forward to new ScienceClic English videos. They are the highest quality science education videos available anywhere on the internet and I am so grateful for all the time and effort that obviously goes into them. Thank you thank you thank you!
Never seen a better explanation with basics
its always such a treat when this channel uploads, hands down the best explanations of physics on and outside of youtube
These are the best science videos on CZcams, thank you so much for making these with such attention to detail.
why does this make so much more sense than it did in school
It's very well presented, but next week it will be gone from our minds. Somehow reading a book works better for remembering this stuff!
@@ab8jeh nah these type of videos give the sense how things are actually layered and related to eachother. The content isn't meant to really be remembered but rather is a tool for interpretation; such that the content you eventually do have to remember can be remembered and understood easier
Because it's wrong.
Your videos are so amazing not only because you illustrate and explain such complex topics in such understandable ways, but also because you bring up ideas that I've never even heard before. For some reason, even among science educators, you connect dots that are always left unconnected by others.
The amazing thing is the author is 24 year old, and my feeling he has an understanding of Physics that is often superior to many Physics professors.
Whoever writes and produces these videos is a genius at explaining ideas.
oh wow! this is a perfect explanation! the first time I have ever finally understood what magnetism actually is, and I'm 40. this should be mandatory viewing in any science class. amazing work, thank you so much for this!
another pre example is your video on QFT
I didn't know special relativity could have that much of an effect on an object moving so slow compared to the speed of light. I feel like we're taught special relativity is some far-off concept only applicable to things like space travel, so to have it explain something so useful to our everyday lives bridges that gap. Fantastic work, as always!!!
The video didn't claim any specific speeds or effects.
However, it is true that this effect is only noticeable at high fractions of the speed of light, which means for actual electrical circuits it is never actually observed because the electrons are barely moving in relation to the protons. So even an object moving very fast next to the cable will see the photons and electrons traveling in the same direction at nearly the same speed.
This is more of a thought experiment.
😅😅
Excellent video. I finally have some grasp on what magnetism is
‘The Best Channel’ of Science. Literally, Science Clic and Arvin Ash are the only two channels I watch of science. Both are ‘The Best’. ❤️❤️❤️
This video tells the story of a whole semester in short. Loved it!👍
That was the very best and simplest explanation I have ever seen. Nicely done.
never have i seen such simplicity and comprehensiveness combined into a single animated video about EM theory
25+ years of trying to understand this and this guy gets it through in less than 10 mins. Damn it, best science channel ever!!!
Every video is so well illustrated and deeply worked upon, it's just perfect! And watching all these videos just comforts and settles that part of my brain which can have doubts any moment. Thank you so much for all your efforts!
Alessandro, you have a tremendous gift for popularizing scientific topics; every video you produce is a gem and comforts me in my belief that no subject is too difficult to understand if it is well explained; thank you for your work!
To explain it this well, you have to understand it this well first, and it's clear that not many people out there do.
I have been searching all over the Web for such explanation....but finally.. this is the answer to my questions..thank a lot
The analogy at the beggining is exceptionally effective!
I am just feeling very frustrated why I am checking your channel so late 😕 hands down bro this is so good!!
These are really great and passionately made videos. Physics is beautiful.
this was astonishingly good. the relativity origins of magnetism was a head-tripping section
best video in internet for electromagnetic field i found so far.thank you so much.
This makes so much sense! I have a deeper understanding and really appreciate this video
Dude You crushed it on this one, connected all the dots and perfectly expressed it all visually, 👌🏼 You’re skills are insanely impressive, the best I’ve ever seen, not even joking lol.
This is immense. So simplified.
This channel is soooo underrated
I kind of lost it halfway, why does the apple not experience a pull towards the electrons when it's motionless? Shouldn't it be that by the presented logic, electrons are moving and so they are more condensed than the protons (which are not), and so there are more of them => more pull?
Also, we got an intuitive explanation on why certain particles can repel each other (ball being passed around in space as our virtual photon), but what intuitive explanation is there for attraction?
For your first question, we suppose that the wire is neutrally charged in the initial frame of reference. This means that there would be slightly less electrons than protons in the wire, such that, when the electrons move, they get contracted exactly the right amount to compensate the protons.
For your second question, there is indeed no good image that I know of to picture attraction by virtual particles. One analogy I like to use it to imagine that the two people are not exchanging a ball but rather a boomerang : they throw the boomerang towards the exterior, which pushes them back closer to each other.
In the stationary reference frame, where only the electrons are moving, it is supposed that the electrons and protons are equally dense in the wire. That's the setup for the thought experiment. It's a little confusing because he first showed the electrons as motionless as well, but the setup is really that they are in motion and equally dense as the protons.
Because the wire at rest is electrically neutral. We can just measure this.
You can try to think about what happens when you turn on the current that ensures this but that gets _really_ complicated. The upshot is that the wire is neutral before you turn on the current and once the current is stable, but not necessarily while the current builds up.
I think ScienceClic have a video where they mention a boomerang analogy. Instead of throwing a ball at each other, they throw a boomerang away from each other which then travels around and hits the other particle from the other side, each time imparting momentum that pushes them together.
Otherwise you just sort of have to accept that virtual particles can have negative momentum.
@@ScienceClicEN Gotcha! That helps, thanks for replying, and thanks for the jaw droppingly mind-bending content you deliver with every video!
Would you believe that I was just checking your channel in months and saying "damn they disappeared". This channel's visualization style was copied by many channels btw!
Edit: I think I never heard this intuition as an explanation for electromagnetic repulsion. What a gem! But can it explain attraction too? I guess I should finish the video before I comment LOL
Once again you have taken a complicated subject and made it understandable. Thank you.
It’s a delight to watch this video over and over again. Thank you for your hard work.
Your channel is really really great because I had almost lost touch in Electric and Magnetism but this entire video really helped me to summarize almost all theoretical points that once I learnt during class 12th days! 💖
Oh my God I can't wait, thank you so much! I am now about to learn something from you that I never knew before. All thanks to you, and for that I thank you from the bottom of my heart! Every single one of your videos are so great because you teach people in a way that we can all understand. And also by the way thanks for keeping the music the same, it is the absolute best music for the background for learning.
This is one of the most deeply impactful videos I've ever watched, believe it or not. Absolute legend. 2 in the morning I realize I want to understand how nuclear reactors work (and expand from there into every fundamental aspect of electricity) and this was my starting point, how electromagnetic fields work and anything around it.
Excellent!! This video clarifies a bunch of stuff I vaguely remember trying to learn a long time ago, like how electric current plus special relativity yields magnetism. Really good presentation and animation. Thanks for making this video.
Fab video. On ice, standing facing away from each other, throwing a boomerang away from the catcher would cause both to move closer. Bit convoluted :)
This was incredibly good! I really liked the part about how electromagnetic energy propagates.
The best description of where charge originates I've heard
Wow. Just, wow. Never seen such an intuitive explanation on the relation between special relativity and electromagnetism. ♡
Phenomenal! As a physics student in university you’ve blown my mind, no one ever took the time to give me such explanations
An extremely well explained phenomena . Merci beaucoup
Waited so long for this and it was worth the wait
Pretty much summed up a full semester of intro e&m, beautiful
Damn I've never had the magnetic force described as clearly as this ever in my 28 years of life. Finally makes sense why electric and magnetic forces are a singular force, the same force viewed from a different frame of reference, and that special relativity is responsible makes this possible - i.e. requiring motion to become apparent. Incredible video as always.
I dont think there are many videos on youtube that explain both the exchange of virtual particles and how magnetism is a consequence of special relativity. Even those that do usually leave out permanent magnets. You really covered all bases here. 👍
Some criticism:
It was apparent how repulsion between like charges works but i didnt really understand how two particles could attract each other by exchanging photons.
Ive heard that some particle physicists believe that magnetic monopoles do exist after all. It would be interesting to hear how that could work.
I agree, regarding: "It was apparent how repulsion between like charges works but i didnt really understand how two particles could attract each other by exchanging photons." It seems the explanation of attraction was neglected, as the motivation of throwing the ball from the intro doesn't seem to neatly map onto an exchange of photons between opposite charges, it begs further discussion. Also, regarding Maxwell's second equation-it's not a fundamental law that the equation equals zero, but rather the value was set to zero as a choice to reject the magnetic monopole. Dirac has some things to say about this: en.wikipedia.org/wiki/Magnetic_monopole#Dirac_string -- I'm not quite as optimistic about their existence, but they are not categorically forbidden under the theory and equations of electromagnetism (kind of the opposite).
@@Alex-nb7on
I was also troubled, and was looking for a critical comment among the flurry of unbridle praise. But I think the implication is buried between the lines that _virtual_ particles are able to be endowed with the property of negative momentum. Since virtual photons are nothing but constructs arising from the field, and not particles _at all,_ they escape the prescription that they must necessarily have mass, and even a _proscription_ that they cannot have a negative mass.
Search "magnetic monopoles and PBS spacetime" here on youtube if you haven't done so by now. They have a great video on the topic of monopoles and how quantum mechanics suggests that they might be possible (despite classical theory indicating otherwise).
Clear, short with no unnecessary hype. Great content
This has to be the best science channel!
Nice! Really excited to see more excellent content from this channel. Although in that last example, are we sure that magnets actually falling, maybe it's the coil rising up to meet it lol.
Really appreciate new video of the deeper dive of the Electromagnetic field! Question: the exchange of virtual photons can explain the same type of particles repel each other, but how does it explains the opposite particles attract each other?
I am not a physicist but as I understand it virtual particles have no requirement to be created before absorbed (so it will travel back in time). So when its taken before created then it can create attraction.
I had the same question. The Virtual Photon seems to be an abstraction to try to explain electric forces en.wikipedia.org/wiki/Virtual_photon
Virtual Photons with negative energy causes attraction ... but IMHO is kinda hand-wavy
This is amazingly intuitive!
You are a genius. I would have never understood these concepts this beautifully without watching your movie here. Thank you!
Wow! i got chills watching this explanation of electromagnetism. You, sir, deserve a Nobel Prize ! Very well done !
If a proton and an electron exchange virtual photons, then why do they attract each other? Two electrons are repelled by the same exchange.
Protons emits photons. Whereas electrons absorb photons. This phenomenon creates a momentum within the proton and electron and thus they attract each other
Really good explanation! Helped me to visualize the electromagnetic process.
Thank you so much to put such a comprehensive and concise lecture of foundations of electromagnetism. I wish this video was available when I was taking the course long time ago…
Thank you for the amazing content as always!!
I love this channel soo much i am studying electromagnetism in school but the stuff written in the textbook is quite unsatisfactory this helped me a lot thant you
What an amazing time we live in. 1. There are brilliant people that understand these complex topics and are willing to make cool videos. 2. Animation software has evolved to easily illustrate these concepts. 3. Finally, CZcams for distributing this content to the masses anytime, anywhere.
This is the best video I've found so far explaining this phenomenon! Explaining the Virtual Particles first made me understand this way better for some reason :)
Great video. I liked the starting example on how repulsion worked. It would have been great if another example of attraction was included. How do the virtual photons help pull two particles (electron and a photon) together. In a bigger example, how does a magnet pull another object towards it? I always wondered about this.
The virtuality of virtual photons does not lie in their fleeting evanescent existence _as particles._ They are not particles at all. Their virtuality is in that they are imposter-artifacts in the field that temporally behave with real particles as though they were the real deal. It's the difference between a dollar bill and a check for one dollar. They can thus have peculiar properties such as no momentum, or even negative momentum (=they can behave like a 1-dollar IOU... just the opposite sense of a dollar)
As long as the latter doesn't bugger-up the particle's otherwise photon- _like_ attributes with respect to the other actors in the interaction, yes, it can exert a yank, instead of a yeet before it disappears.
Because it is not a real particle, it doesn't have to have real mass, and can seem to defy Newton.
A moment of silence of the people who are still searching for this scientific masterpiece !
Your explanation of physical phenomena is outstanding !
Mind blown, wish i had this truly exceptional way of understanding the concepts of physics. You're blessed. Keep up the good work. We highly appreciate it.
Thank you so much for making me finally understand the basic relationship between the electric and magnetic component of the electromagnetic force.
top notch as always, great animations, shout out to your animator! Also I love how you jump from "simple" high-school physics straight to uni-lvl-physics. It actually helps a lot tying the concepts togetherr. Thx!
I love all of your videos, but I'm still really confused as to how virtual photons can lead to forces of attraction.
Repulsion makes intuitive sense, but I just can't get my head around the attraction.
Can someone help me out?
I was wondering that too.
@@moukafaslouka4796 hopefully someone in the know will pop into this comment thread in the near future :D
As a layperson, I enjoy ScienceClic videos. I understand the videos are probably really meant to just display 'concepts', but sometimes my brain gets fastidious, so at the risk of being a “putz”, I'd like to suggest adding a little extra wiring to complete the electrical circuits in future videos, as it would enhance the soundness/completeness of the ideas shown.
For example, at the end of the video, the graphics show the concept of a magnet slowing as it drops through a coil of wire. The magnet would fall through almost as fast as if the coil wasn't there. But, if the two ends of the coil were drawn electrically connected, the circuit would be complete, the electrons could really flow creating the shown magnetic field, and then the falling magnet would slow significantly.
At 12:27, the left end of the coil should also be used (again to complete a circuit and enhance the concept). As the magnet moves in one direction (forward?), the grouping of electrons (large blue blobs) flow through the wire in a particular direction. When the magnet slows and then starts to move backwards, the blobs should reverse direction, as a completed circuit of the shown system would really be producing alternating current (not pulsating DC). The graphics at around 12:19 do show this forward-backward of electrons properly (assuming a complete circuit - not shown). Perhaps have the two coil ends go to a light bulb to complete the circuit. The bulb brightens and dims during the magnet acceleration & deceleration along with the forward & backward motion (assuming it is easy & quick enough to add to graphics).
This is my favorite science channel on youtube by far
Keep up the excellent content!
7:36 The Magnetic Force
So why isn't the apple attracted when it is motionless?
From the apples frame of reference this means the electrons are moving faster than the protons and are contracted and should be more condensed together than the slower moving protons
( in the wire)
Basically, why isnt the opposite true when the apple is at rest relative to the wire?
Because this is all garbage suedo science. Absolute rott. Gobbledygook. Only the feeble minded go " oooo so thats how it works "
I hope he clapped his hands to wake his audience up at the end.
What a joke.
He explains it very well in the video. They cancel each other out until movement is introduced. It's right there in the video. Were you not paying attention?
Not a single one of your videos is even slightly less than 100% awesomeness and after so many days your awesomeness has not changed a bit...
Most understandable explanation of electromagnetism I have ever seen.
I get the momentum of exchanging virtual photons could be said to represent repulsion. Then what causes attraction? How can you explain exchanging a negative and positive virtual photon, giving each particle momentum in the same direction? You would think the electron would still get repelled, like it did when it exchanged in the same exact way with another electron. Same goes with the proton, the momentum explanation totally breaks down here. The electron can do the very same action and go in two opposite directions depending on the other particle.
I have the same doubt
Just wanted to know, how does special relativity affect the electrons when they are moving in the wire? i.e. When the apple is stationary, wouldn't the movement of the electrons cause length contraction relative to stationary observers? This would mean that the apple should be attracted to the wire, due to the increased density of negative charges. Perhaps there is a subtle point here that I'm not able to grasp.
Good question, don't get it either...
Agree. Also, electrons speed in a wire is around 10 centimeters per hour. Not enough for any relativistic effect.
Yes, this is exactly what I am wondering about. It should not matter what is moving against what. All movement are relative therefore it seems to me that stationary positively charged apple should be attracted to wire with flowing electricity by imbalance of forces in the same manner as moving charged apple. Any explanation what I get wrong?
@@balabuyew I think the explanation for this is that due to the sheer number of particles involved, summing the extremely small contribution of each one results in a significant overall effect. Though, I'm not too sure about the details, electric current is measured in Coulombs/sec, meaning that given even a small drift velocity, the number of particles moving past a given point in the wire is quite significant: approximately the equivalent of 6.242 x 10^18 electrons per second.
Finally some peeps are questioning this garbage !
One of the best explanations of the electromagnetic phenomena, thanks
Virtual photons? That's a new one for me. Btw, out of all the videos on CZcams on electric fields vs magnetic fields, this one is the best and maybe the only one that can explain this simple enough for anyone to grasp. I subbed when I thought of what else I might learn from this format of teaching.