Many Moving Magnets Melting Metal

[Music] all right everyone welcome back to my lab so this here in front of me is a 6-1 listeroid diesel engine it's basically a replication of the old english lister diesel engines it looks like an antique but it's actually only like 14 years old it's fairly new we use it here at the ranch to charge batteries and stuff like when there's no solar or wind it doesn't run that often but you know it's been working for us for quite some time it's a really cool engine definitely think about doing a video on it specifically at some point but not today today i've got a bag of these super strong neodymium magnets and i've been itching to stick them to the flywheel and see what kind of cool sciency stuff we can do from a ring of spinning magnets now of course for safety we should check to make sure that the magnets can actually stick so let's put them on here let's spread them out so it's a little bit balanced the flywheels are actually self-balancing a little bit so it doesn't really matter but it's probably a good idea anyway okay i don't think the magnets are going to come off this only rotates at about 600 rpm 10 revolutions per second it's a 27-inch flywheel i'm sure somebody can figure out what the g-forces are there but they're not particularly large anyway to start it we got a hand crank we never put a starter on there i never needed it because it starts super easy see just turn on the fuel there get it turning over and then open the valves and drop the valves and then it's going see i gotta stay over here get the magnets fly off there we are up steve magnets seem to be doing just fine turn off the fuel and let it come to a stop so much more easy to start than the model t over there model t starts the same way but you really have to sit and crank it the first thing i wanted to try was to make a crude electrical generator to do this all i need is a coil of wire which i made by wrapping a long piece of copper wire around a bolt gluing the coils with super glue so they don't come apart and then removing it from the bolt i then attached two led lights to the coil so we can observe the electricity that's being produced so i've got a blue and a white and they are reversed of each other and the reason for that is the electrical current that will be produced is alternating so when the magnetic field is starting so when the magnet is coming across the coil apparently those are iron it'll create it'll induce an electric current in the coil going one way and then as the magnets leaving it'll create a current going the other way so one way the white light bulb will light up and the other way the blue one will [Applause] okay there we go the engine's running i've got magnets flying past at freeway speeds see what happens when we carefully put the coil of wire underneath where the magnets are flying and nothing the lights did not illuminate what's wrong so there was an electric current being induced in this coil the problem is it wasn't very strong but there's a pretty easy way to make it much more efficient and that is to replace the bolt so pull this out so we can work on it stick the bolt up through this board there we go and then put the coil back on the bolt now what the iron does is it's ferromagnetic it basically becomes a magnet when you put in an external magnetic field this amplifies the magnetic field and essentially directs it so instead of having the magnetic field go across the top it forces it to go down through the windings and that is what is really important for making the electrical power see it's basically like you're making electromagnet except in reverse using the magnet to produce the electricity of course just putting the magnet here isn't going to make power that would violate conservation of energy the magnetic field has to be changing and the faster the magnetic field changes the more power that will be produced all right start the engine there we go we got some flashing lights all right [Applause] we are at full speed see both lights are flashing and flash as the magnet goes past let me get the high-speed camera out and let's see if we can uh get a better shot of this so we run the video forward you can see the flywheel is turning the magnet comes near the coil you see the blue light illuminates and then as the magnet crosses over and starts to leave the blue light goes out and the white light turns on and then as the magnet leaves both lights go out because there's no more electrical current and we run it forward to the other magnet it's right there now watch this white and then blue because this magnet has a different orientation so now let's see what happens when we put on the rest of the magnets and make a complete ring around the entire flywheel now how did i get that lucky look at that it's perfect fit 326 of these very strong neodymium magnets stuck onto the flywheel they're arranged north south north south all right well let's start it up and see what it does to those little leds yeah now that i think about it the magnetic field is going to be changing twice as much because we're going from north all the way to south rather than just from zero to north so it might actually burn the lights out but here we go they're on it's making a whirring noise looks like the lights are oh the blue one just burned out well the white one burned out too just as soon as i got the high speed camera online i'll see if i can uh wiring another one or something so i found a pretty simple work around see if i just move the coil away from the magnets the voltage drops so the lights don't burn out i can adjust it nice get the camera going on it that was pretty fun and now i've got a little light that lights up when the engine's running how cute on that last shot i was filming at 8 000 frames per second to get a good video of them blinking as you know these magnets were going by quite rapidly so i needed the high frame rate anyway i'm moving on with the science here what would happen if i took this coil wire which was quite warm and shorted out all the windings maybe got even warmer and melded into a blob of metal you know something like a bullet here well it would still actually induce current the currents would not be as useful you know i wouldn't be able to plug in a light and get it to light up but the currents would still occur so let's see what happens when i put a solid piece of metal next to these moving magnets so here's one of the silver bullets that grant thompson and i made when i place it next to the spinning magnets the first thing i notice is a strong drag force pulling the bullet along with the magnets this is the same force that caused the coins to slow down in my coin sorter essentially conductive materials require work in order to move through a magnetic field due to electrical eddy currents that are generated in the metal that take energy to create the second force that is very noticeable is the torque that's being put on the bullet it wants to spin i can show this better by placing a foil ball inside of a test tube the ball rotates quite rapidly and what's causing this is simply that the magnetic field is stronger near the magnets the third force which i found quite interesting is a repulsive effect that pushing the metal away from the magnets this is caused by the electrical currents generating a magnetic field on their own which mirrors the external magnetic field and since like bulls repel the piece of metal is able to levitate the final effects that i will talk about is the fact that the piece of conductive metal actually heats up in this changing magnetic field the reason for this is the fact that the electrical currents rapidly dissipate turning into heat due to the resistances of the metal let's go back to a coin and see how hot we can get it using this setup um after using the magnets to successfully heat a copper penny enough to melt solder i got the idea in my head to try to melt a bullet so i was having a lot of trouble holding the bullet in the correct place for long enough using the pliers and besides the pliers are pulling the heat out of the bullet keeping it from reaching high temperatures so let's try mounting it just like on a piece of wood here like carve a little indentation for the bullet to sit so it can ride right along the magnets okay you can hear the shot balance flywheels that's what that rattling noise is oh see that right there that's why i was going slow the bullet wants to jump out it's trying to turn that's what's going on well so i've tied the bullet down with some copper wire let's see if that works let's spin this up seems all right let's start the engine so [Applause] well it's hot but it didn't melt the lead handling the bullet after taking it away from the magnets i estimate that the highest temperature that it achieved was only a little bit above 100 degrees celsius like i put some spit on there and the spit was able to boil but it didn't sizzle so hot enough to burn you but just nowhere close to actually melting the lead not available of the copper and the lead wasn't able to melt well first of all the solder was actually a lead tin alloy which has a slightly lower melting point than the lead so it's a little bit easier to melt but i think the biggest issue is the fact that the penny was a lot thicker much thicker copper you see this bullet here has been broke apart so i can see the thickness of the copper jacket it's only like a third of a millimeter thick now if you've ever torn apart a transformer you'll know that the iron core that directs the magnetic field through the windings is usually made out of thin metal plates thin leaves of steel instead of a solid block now partly that's so that it's easier to manufacture but it's also to limit the thickness of the metal that the eddy currents can develop in so the thicker the metal the more voltage potential you can generate across it and the more inductive heating you will have so making thin metal pieces reduces your inductive losses it also means that thin pieces of metal are harder to heat now the lead itself is quite thick you know this is a 45 caliber bullet but also its electrical conductivity is very low it's like a tenth out of copper plus it drops dramatically as you heat it so the the lead isn't contributing to the heating very much and the copper jacket isn't contributing very much either so the total heating before the wind of the flywheel is able to take away more heat than is being added is ended up being around 100 degrees celsius much lower than we needed there's a few things i could do maybe uh stronger faster magnets is always an option but i think for now in this video we're just going to cheat a little bit let's just replace the lead with something easier to melt so we can still see a bullet melting but it just won't have to get as hot so well first of all i've got a blow torch here melt the lid that's more like it okay to replace the lead we're going to make fields metal so this alloy calls for 50 indium 30 bismuth and about 15 10. those numbers are not exact but they don't really need to be so let's just uh zap this with some heat [Applause] this metal alloy has about the same melting point as candle wax so it's very easy to handle anyway let's fill up the bullet oh might need a little bit more metal got some more made up here just break a piece off [Music] [Applause] so there you have it a bullet or at least something that could technically be used as a bullet melting well partially using magnets well hope you enjoyed i'll see you next time

Channel: Cody'sLab

Views: 1,241,944

Rating: 4.9135675 out of 5

Keywords:

Id: l8PxXZoHTVU

Length: 20min 20sec (1220 seconds)

Published: Sat Sep 19 2020

Reddit Comments

[u/sticky-bit]

I guess this is the polished, finished version?

Due to the magic of "acting" on camera, Cody has somehow squeezed an extra magnet in line with the others on a flywheel. <j/k>

Anyway I wanted to throw this up before u\Robo-Cody did because I suspect he's not programmed to detect that this public video is nearly the same as the prior one mentioned on Twitter almost a day before.