If you start commenting on bad videos you will have a busy hobby for the rest of your life. But there are also reasons to take a look at these videos, for example the math video is horrible but the path of calculation shown is rather beautiful. The other video is about magnetism and when I viewed it for the first time it was really late at night and only after a good night sleep I realized how horribly bad that video was.
But it was the magnetism video that made me look up the average size of the so called magnetic domains and that was when I found that PERFECT gif. So I cannot say it was all a waste of time, that perfect gif is made with something that is named a Kerr microscope and with such a device you can make magnetic domains visible.
Years ago, if memory serves it was Feb 2017, I was studying so called ‘racetrack memory’ that was under development by IBM. That IBM project failed because they kept on hanging to electrons being ‘tiny magnets’ with two magnetic poles, because that is likely not true all their work failed. Anyway they came up with the fact that you cannot move magnetic domains with magnetic fields and I totally freaked out. Late at night I realized that within my broader development of understanding magnetism at the electron level, the IBM findings were logical if magnetic domains in say Iron or so, always have a surplus of either north pole monopole electrons or south pole monopole electrons. Domain walls separate the two kinds of magnetic domains. Itis a pity that about five years back I never heard of those Kerr microscopes.
Again I want to highlight that I do not want to convince anybody that electrons are the long sought magnetic monopoles. I have done that for six or seven years and it was only in this year 2021 that I arrived at the conclusion that physics professors are just as stupid as the average math professor. It is a pile of garbage so it is not much of a miracle that six or seven years of trying to apply logic did not work at all. So from this year on going into the future the physics professors have the same status as the math professors: A pile of rotten garbage that you must avoid at all times at all costs needed.

After having said that, this post is five pictures long where I comment on the two horrible videos. Below that I will post the two videos so you can see for yourself (or may be you want to see them first). And at the end you can see that perfect gif where magnetic domains change in size due to the application of an external magnetic field. Also back in 2017 I more or less figured out how magnetic domains will change if you approach a piece of iron with a permanent magnet. What you see in the gif is more or less precisely that: Some domains grow while domains next to that shrink.

Ok, here we go:

Now we can go to the first video, the math one:

I found the magnetics video by doing an internet seach on ‘The Stern-Gerlach experiment for iron’. It is disappointing that almost no significant results are there. Some of stuff out of the 2030-ties of the last century but that was all behind pay walls. Very high in the rankings came the next video that uses iron filings to mimic or imitate the Stern-Gerlach experiment. The video guy should have used magnets on only one side, if that resulted into attraction & repulsion of the iron filings he would have gotten a standing ovation from me. Without any insult; the way he executed this experiment is a true disaster only showing he does not understand why the SG experiment is so important.
And by the way: If my idea of electrons being magnetic monopoles is in fact correct, you do not have to use inhomogeneous magnetic fields. Everything will do; even the most constant magnetic field in space and in time will do. But again after so many years of talking to deaf ears from stupid physics people, I have lost my desire to convince anybody any longer..

Ok, I have never hung any animated gif into this WordPress website so let’s check it out if it works properly:

I found this animated gif in a wiki: Magnetic domain.
That was it for this post. Thanks for your attention.