How Magnets Work - Ask a Spaceman!

what's happening inside of magna I know that's a very zen statement but the weirdest thing about magnetic fields in general is that in order to create a magnetic field you must be in motion and in order to respond to a magnetic field you must also be in motion magnetic fields and motion go together like two things that go together I don't have any examples off the top of my head but you get the idea of magnetism in motion if you just have an electric charge just hanging out mining its own business that electric charge will have in electric field this electric field will point in all directions and if you're another charge you will respond to that electric field all right but if you send that charge in motion if you give it a little flick a little kick if it starts moving then it will start to generate a magnetic field in this magnetic field is always perpendicular to the direction of motion so if a charge is coming right at you like this the magnetic field wraps around it as almost like a cylinder or a helix there's a bunch of ways to visualize this this magnetic field being generated by this moving charge so how can a bar magnet that is very obviously not moving have a magnetic field well the answer is what's happening microscopically yes macroscopically this bar magnet they like stick on my fridge is not moving around obviously but the things inside of it are moving so this bar magnet is made of molecules atoms the atoms have protons and neutrons and they have electrons and electrons have some very fundamental properties if if you just needed to list the fundamental properties of an electron there be its mass there'd be its charge its electric charge in there would be its spin the spin is the name we give to a fundamental property of the electron in fact a fundamental property of all particles we're when describing spin it's very easy to use analogies and I'm about to use an analogy but don't let the analogy tell you too much because it can lead you astray spin is a fundamentally a very quantum thing spin is fundamentally not something that we have a good intuition for you can pretend however you can pretend that an electron is a tiny little metal ball that is spinning really fast and you can pretend that this tiny little metal ball has a charge on it and spinning really fast and it's also orbiting its atomic nucleus now electrons don't really orbit atomic nuclei and I have no idea how this picture of electrons orbiting nucleus become became like the logo for science even though it's a hundred years out of date but whatever that's a different episode the electrons aren't really orbiting the nucleus they're not really spinning on their axis like a tiny tiny little planet in its little tiny microscopic solar system it's absolutely not doing that and if you think it's doing that then you this line of thinking will lead to some conclusions and predictions that violate experiment so you know you're wrong but for the purposes the magnetism we can pretend this is exactly what's going on so we're just playing pretend because when it comes to magnetism this picture works and if you have a charge like a little metal ball that's spinning really fast it has electric charge on that is charged in motion that gives you a magnetic field so each individual electron tiny little electron has a magnetic field associated with it aha in a normal material like - chalkboard or whatever the electrons are like to pair up well they'll be one electron that spins up and it will be matched with an electron that spins down their magnetic fields cancel each other out so you get no net magnetism if I measure the magnetic field as desc I'm not really gonna measure much some materials however have unpaired electrons like like bachelor or bachelorette electrons free-floating electrons now most of the time in most materials when this happens the electrons can do whatever they want they have all sorts of weird random orientations and again there's no magnetic field but in some very special materials that we call say permanent magnets there all the electrons are at least most of the electrons line up together that boom-boom-boom-boom-boom and you can add magnetic fields together so you get a tiny little contribution from this one a tiny one a tiny one tiny one time you add it up together and you get a big magnetic field in the shape of this magnetic field is exactly what you would expect from having a bunch of little charged metal balls spinning around and orbiting their atomic nuclei so for that purposes this is how you get the big magnetic field now a magnet like a fridge magnet is made of strips of materials so that they alternate back and forth so that on one side the magnetic fields add up together and this is the side you attach to your fridge and then the other side they cancel out this is the side you put the the cheesy souvenir on and the electrons in the metal of your fridge are mostly uncoordinated doing whatever the heck they want but in the presence of a strong magnetic field they line up together and then they produce their own magnetic field and then these two magnetic fields are able to lock together and you get this wonderful effect of being able to stick a fridge magnet onto your fridge even though the magnet itself isn't moving it's because the magnetic field of your fridge magnet is made up of a bunch of tiny tiny little charges in motion that generate their own magnetic field and get to and together to create a big magnetic field so there you go that's how magnets work thank you so much for watching if you enjoyed this please don't forget to Like and subscribe and make sure notifications are turned on so you know when I go live and also go to patreon.com slash p.m. Sutter there's a link somewhere around my face right now so you can keep these videos come in thank you

Channel: Dr. Paul M. Sutter

Views: 16,568

Keywords: space, cosmos, universe, astronomy, physics, astrophysics, cosmology, science, magnetism, magnetic fields, magnets

Id: 6uwjqy2HCgY

Length: 7min 17sec (437 seconds)

Published: Wed Sep 05 2018