Magnetic Hysteresis or I KNOW WHAT YOUR MAGNET DID LAST SUMMER | Doc Physics
HTML-код
- Опубликовано: 24 фев 2014
- When I was your age, kids played with magnets and threw scissors at each other instead of texting. It was a simpler time.
You probably are wondering what distinguishes hard and soft magnetic materials from each other. Well, this is it.
Here are some ways to spell hysteresis wrong: histeresis, hysterisis, hizthérèsez, histeriasis, hystirysis, hystirisis. Can you come up with more?
i picture this guy rolling into class on a skateboard wearing a backwards cap.
LOL I can see that.
you know i picture this guy as a cool stud in shorts with his cap backwards and marker in one hand proving E=mc2 like a boss
Yeah, with gold chains and bracelets
Bruh ! 😂
YES, Finally a worthwhile video explaining concepts like thin an *engaging* way rather than some old fart in the distance on a green chalkboard moaning on hour an hour and a half, You have rightly earned my subscribe!
Power Max Thanks, yo. We'll all be old farts someday, though. We'll have to be careful not to bore the kids then!
Doc Schuster Haha I know, I always try to teach and explain difficult concepts using analogies and examples exactly like you, though not formally since I have not yet earned any degrees in engineering or physics, though I love to learn stuff, especially when I want to select the proper transformer (like a big chunky 60Hz iron core vs tiny ferrite or air-core RF Xformer) for a given project.
I actually still haven't finished watched the video, I am at 11:30 and was 'eureka' for me since it not only made the 'saturation' concept clear to me, but also the fact that magnetism doesn't just go away so easily by removing the external field, that it learns around, just like what I discovered when I was pulsing current through a wire and discovered that a nail became permanently magnetized in my workshop/lab.
Power Max Pleased to meet you! You seem very cool!
You just made me think of my teacher standing up, fumbling through his notes an reading them to himself.
You are seriously a life saver! So refreshing to have someone explain colloquialy... This is how you explain a concept well and quickly.. I dont understand people who try and overcomplicate concepts for nothing
I don't know how I ended up here, but that was the most educational 20min of my life. I love when someone is able to explain and demonstrate a topic so well that you're left thinking at the end "yeah, I already knew all of those concepts." Yet collectively you have never put them all together to make a cohesive thought or conclusion. Thank you for explaining.
I wish there was more of you at our college of engineering. Would make life so much easier.
"Lets name this sucker", hahah
Great explanation, Thanx.
this was beautifully and hilariously explained, thank you
You know how to teach unlike my lecturer!! thank you so much, and the humour helps remember the concept even better :)
AT THE END OF THE VIDEO I REALISED I DIDNT HAVE TO TAKE ANY NOTES BECAUSE YOU TAUGHT SOOOOOOOOOOO WELL ALL THE ANALOGIES AND THE ENERGY YOU HAD WAS ENOUGH TO BURN WHAT YOU SAID INTO MY HEAD. A SOLID 10/10 WELL DONE
I always find hysteresis scary. It reminds me of how lucky we have been so far that it is not real. Actual, fundamental hysteresis would be a devastating blow to physics. Not fatal maybe, but an enormous setback. Sharing my fear makes me a little less afraid, so that is what I'll do.
A basic feature of fundamental theories, classical Newtonian or quantum mechanical, is that it is possible in principle to specify an initial state of a system, and then the theory (again in principle) tells us everything about the future of that system. This also applies to spin, so one might wonder how ferromagnetic hysteresis is possible at all. The fundamental equations (say a many particle Schrödinger equation with magnetic interaction terms in the Hamiltonian) simply allow any initial state to evolve uniquely in time. So there should not be any hysteresis at all.
The answer is basically this video. The story you tell shows explicitly how hysteresis does NOT occur, but is only apparent. If we think that the state of a piece of iron is adequately specified by giving its (unperturbed) magnetic field, we are mistaken. The configuration of the domains and their boundaries is also an essential part of the state of the system. If we choose to ignore them, we will not have a unique time evolution. If we take them into consideration, as you do in the video, the whole system becomes an ordinary case of a state whose future depends on the current state, but not on its past. You go through it, step by step. So thank you for showing the absence of hysteresis :-)
In a few minutes I'll go to bed, switch off the lights and try to sleep, if I can. But I'm not sure I can. Suppose there would actually be hysteresis that no one can explain away by including more properties into the state, as you did. Then the future of a system would actually, really, unavoidably, depend on its (entire) past. Quantum mechanics would be wrong, and so would Newton. The whole mechanism of partial differential equations would not be relevant to physics. We would, in short, have almost nothing in the way of physical theory. When I imagine this, I cannot help but feel horror.
Thank you for listening to my fear. It really helps. Goodnight. :-)
i'm confused.. He just demonstrated hysteresis and newtonian physics are still intact. What is your fear?
You're simply wrong. Mind you that a little learning is a very dangerous thing.
you are the best an funniest teacher. thanks for being you
Damn i wish you were my teacher. :o
Great explanation !!
Great video! I'm in NDI school right now and we're learning about Mag Particle Inspections, specifically the Hysteresis Loop. All of our material is extremely technical and sometimes hard to understand or interpret (without a dictionary or prior knowledge) So, this video explained it to me very well.. A little sporadic but it definitely got to me! Thank you!
This is absolutely delightful and brilliant. I'm cracking up and learning so much :D
Very good video! Thank you for that! To bring a ferromagnet back to its (0,0) point on your B residual vs B ext graph, you can heat it to its Curie temperature rather than hitting it!
Red Power Ranger An excellent point!
Brilliant explanation, its made a lot of things fall into place about magnetism and greatly helped with my studies for next months exams.
Thanks a million, i don't know if you are but you would make an excellent teacher.
I watched a few of your videos. They may take a while to finish because they are so comprehensive because of the subject matter. But when I get to the end of the video, I seem to love hitting the AH-HA moment. Keep it up!
am in college now...and i came upon this while seaching for lab exp.. reminded me of my high school days (yes i highly depended on Doc Schuster's lectures during my school days) .. and glad to come across it again :)
your enthusiasm is appreciable
"Who knoooowws?" HAHAHHA best part, you're a cool prof I guess, if you were hehe
Damn I wish I was as excited about magnetostatics as you. Cheers for making me smile during a torturous library session
this dude is insane
why don't we have more educational content like this these days
I was looking for a slightly more intuitive explanation/example of hysteris to understand the use of a MT NDT Yoke etc. You nailed it sir. Couldn't be better, Thank you
thanks a lot! really nicely explained, keep up the good work
First year of chemical engineering at taipei, videos like these are my saving grace. God bless you😂
Hi Doc, I came across you video here, very nice introductory view about magnetic momentum and domains. Just want to freeze one thing, as you know "saturation" (B=nM) is only theoretically achieved and for most ferromagnet materials, even for non soft ferrites, will not align all domains in a "saturation" scenario as you described here :) . Good job.
omg...you are still making new video....u made me love physics more sir!...
This is like the best explanation of hysteresis. If teachers taught physics this way, the world would have been a better place.
You sir, saved me from a lot of head scratching and hair pulling! Loved the video ☘
holy.. only if I had a teacher as cool as you.. never understood a concept better.. beautiful way of teaching man.. you earned a subscriber!!
You unsubscribe 😂
Good vid.
Thought I would add rather than just mechanical shock you can of course reset the bolt to its magnetic history 'year zero' by heating to a defined temperature - known as the Curie temperature. For steel its about 900 deg C (I think)
13:09 oh thanks that you mentioned H. I was like „nice, but why is it B?“ so yeah. It‘s a great video for understanding the basics.
Nice, especially your clicking device 😁 Also a remark about your voting people analogy for the micro/macro organisation of magnatised objects : I liked it, I think Theoria Apophasis (Ken Wheeler) would call that coherency and point source. You might like his very simple Physics based on pressure mediation in the Eher (inertia and losses of inertia). It's kind of piratry for current scientists but he says that Tesla and Steinmetz already said similar things. Anyway, thanks for the lesson 😊
Nice Presentation :). Keeps the energy of audience throughout the presentation
Of course you meant poop factory.
For the first time I really understand what the heck Hysteresis is all about. Thank you! (excellent metaphor!)
This was a really entertaining and useful video, thank you! :)
Great explanation dude!!!! You rock!!! If you have time upload a video on alternating current and direct current
Explanation is awesome but there was a huge mistake at the very end of video from 20:00-20:10. It is not the residual magnetic flux density Bres which distinguishes the hard and soft magnetic materials. It is the coercive force i.e. magnetic field intensity Hc distinguishes the hard from soft magnetic materials. The wider the graph in lets say x direction the more the harder the material from magnetic point of view.
HELPFULL VIDEO FOR BEGINERS FOR BH CURVE STUDY ...THNX
u are the best when ti comes to explaining concepts
wow. I missed a class, and don't understand what does this Hysteresis on my script even mean. Thank you so much. Don't realise that video from almost 6 years ago is still very very helpful. Thanks again
Thank you sir, I like your sense of humour! :)) I also mannaged to understand how things works with this stuff called hysteresis :)
Awesome! Thank you very much!
Thanks, Awesome explanation!
Thank you very very much! awesome lecture!
Oh man this was so helpful thank you so much, I'm currently learning this but I'm an exchange student so it's all in japanese so often it's really difficult for me to understand the concepts with the language barrier, so my brain's kinda tired at the moment but this made it so clear as well as being absolutely hilarious! Thankyou!!
wow, amazing lecture on hysteresis
Why is he posting no more??
Best hysteresis explanation!
Thanks for lecture vivid
Beautifully explained
Why I didn’t watch that earlier!!!
Great explanation. Thaaank yoou
*Sincere golf clap* Thanks, excellent presentation. You are a unique talent.
Thank you so much for this video!! It really helped survive my final exam :)
What a great and funniest teacher he is? If my school teacher study us like that I cant get fail in my exams
He really deserves a subscribe
unbelievable great video! Thank you so much
absolutely well done here!!!
That was very clear, thanks
Yes roughly but curl at sharp corners of domains boundaries form stable vortexes. Farther away it's like you say. So what can magnetic pixels do with vortexes as a macro particles and what kind of resonant cavities can you form with m pixels? Can you shape saw devices dynamically? Can you beam steer for directed comms with say gammas beams.
Beautiful Explanation . Keep Up the good work :)
Excellent sir
I just watched this at double speed... Best 10 minutes of my life :'D
THANK YOU SO MUCH! Gosh, this video really helps a lot!
"You win!" Subscribed.
You have a such good accent , i like the way u explain , tnx
Great explanation...😀
love the starting that makes it cool
THANK U FOR THE TITLE ND EVERYTHING
What a Greek oracle when "England will take over itself" on 18:10 LOL! Just wait for 2016 and 2020. XD
awesome explanation
Great analogy of taking over England, I love your style
Thanks Dr ❤️
this is the greatest video in the world you don't how enlightened right now that I understand everything
Great video, thanks!
Why don't I have a teacher like you in my school?
You're awesome man!
you're an enormously good teacher
Great explanation thanks
Why didnt i meet you earlier
You r perfect to my pratical thinking
Thank u..so much......
great video bro ... nice explanation
You are awesome sir. I loved this video
I liked the video before i even watched! Title xD
So well explained! Thanks!!
10 years ago but still useful😁👍thank you doc schuster
Amazing explanation
Great video! Subscribed.
Did I just learn how to conquer England alongside learning Physics and some jokes?cool.
"Which way you gonna magnetize?" so funny :)
This is one big heart for you man of science
Thanks from Germany! Great Video!!
This guy is awesome..!
You win! Lol. And normal people call it saturation made me laugh.
really awesome!
he had a small scissors last time and now he has a big scissors. get it haha
you are an amazing teacher
You rock it man!!
After saturation, isn't Bresult supposed to still go up slowly (and linearly) as Bw/o iron increases?
Doc please can you send what exactly hysteresis mean
You are amazing. thank you so much! you saved my day
Thank you, i finally understand !
So Goodd! Loved it so so much!
Amazing! Thx!