Electromagnetic Force Fields VS. Magnetic Cannonball

[Music] hi everyone in this video I'll be attempting to answer the most popular question I received in the comments of my previous video in case you missed that video the topic was on the electrical inductance of copper plates and how they respond to magnetic fields now the question I'll be attempting to answer was prompted by the last experiment I did in that video the experiment was to take a disc of copper in particular this three inch diameter by one inch thick disk of copper and a magnet on a pendulum now when I swing this magnet toward the copper plate we see an interesting result the magnet slows to a stop before actually impacting the copper it's like it loses all of its momentum at the last second now the reason this happens is because an oncoming magnetic field moving toward a conductive surface excites electrons in the material it causes them to orbit in a circular pattern this turns the piece of copper into an effective electromagnet which produces a magnetic field in opposition to the one that is coming towards it this slows the magnet down as most of its momentum is converted either into further kinetic energy in the copper or electrical energy which radiates away as heat after seeing this effect demonstrated many of you left my video with the question of if a magnetic field induced in a copper plate could actually stop a bullet now the bullet would have to be magnetic in order to take advantage of this effect it would need to have a magnetic field that induces current in the copper but presuming a bullet was magnetic could we slow it to a stop with induced magnetic fields now this particular setup is definitely not bulletproof I can prove that just by pulling the magnet back a little bit further and we can see that the magnet does touch the copper if it's given enough momentum it can overcome that induced magnetic field in the copper plate and it does make contact so this set up is inadequate but I do have a few tricks up my sleeve that could make this work but before I get to that I need to actually have something that will fire a magnetic projectile at bullet-like velocities and that's where this little cannon comes in now this cannon is made from a 2-inch diameter acrylic rod and the reason I chose acrylic for the cannon material is I thought it would be really interesting if we could see inside the cannon maybe with my slow motion camera to actually see the powder combusting and the magnet moving down the barrel and things like that I thought it would look really cool this way the way that I made this is I took my piece of acrylic rod and I mounted it in my drill press I actually learned a cool new trick for Center drilling a cylinder on a drill press by first drilling a hole the outside diameter of the cylinder into a two-by-four and then using that as a sturdy mount to hold the cylinder in place while I quart it out with larger drill bits drilling acrylic is a little bit tricky because it heats up so much that you can actually melt and then boil the acrylic plastic around the bit and so you have to be careful not to drill too deeper out so that acrylic can actually boil melt around the bit and then freeze again and then your bit is really locked in there and it's a pain to get out so you want to do it in stages and give the bit time to cool off in between those stages if you see that it's getting too hot and the acrylic is starting to boil once I had the cannon cored out to the inner diameter that I liked I then drilled from the back side to install a hole for a fuse and I wanted to make this in line with the barrel rather than going through the side like a traditional cannon you might see on like a pirate ship I thought that would give the cannon a little bit more strength and a higher pressure rating so the chance of it exploding would be a little bit less likely if I accidentally overloaded the cannon with too much powder I did drill one small hole into the sidewall of the cannon but it didn't go all the way through this is for my mounting solution I tapped threads in this hole so that it could attach to this tripod ball head this not only makes the cannon very easy to aim but the ball head actually can work to absorb some of the recoil when the cannon fires so now that my cannon is made that brings me to my first idea for using the inductance of copper plates to slow down a bullet speed projectile and that is to mount my plates in a vise like this with a gap between them I'm going to attempt to shoot through this gap which should give a long area of travel through the inductive field that will slow the projectile hopefully to a full stop the projectiles that I've chosen to use for this experiment are these small and fifty two grade neodymium magnets now these because of their size are not quite as strong as the larger magnets that I've used in my other demonstrations and so the magnetic field that they induce in the copper is weaker but between these two plates there should be enough magnetic field induced to see at least a little bit of slowing in the projectile at least that's the hope I need my cannon to be aimed exactly between the two plates so in order to do that I'll just look through the other side of the copper plates and align the barrel with the gap visually and this should work pretty well for my first tests with this cannon I loaded it using smokeless gunpowder I did this for the sake of the video because I didn't want smoke obscuring the view of whether or not our magnetic projectile slowed between the copper plates I knew from the start this was not a great idea because the chamber pressure is produced by smokeless gunpowder are very high and it could cause the cannon to explode it also doesn't work very well if it's not given enough back pressure so there's a good chance this isn't going to fire the cannon at all but we'll see what happens when I actually try it it turned out pretty much how I expected I'm certain I could have thrown the projectile harder than it actually exited the barrel of my cannon most of the Gunpowder actually burned in the open air after the cannon had already fired because it just didn't have enough chamber pressure in order to fully combust when it should have fortunately I have some black powder on hand which has meant to burn at pretty much any chamber pressure and will work very well in this little cannon I just hope the smoke doesn't obscure the footage too much once again I've aligned the cannon to fire the magnetic cannonball directly between the two copper plates so we'll see if it slows down well the cannon performed perfectly but I think the sand pouring out of my backstop is a good indicator that the copper plates did not slow the magnet enough to be called bulletproof not by any stretch of the imagination there is one way that we can increase the conductivity of copper and that is to cool it down I have some dry ice here that I'll use to cool down the top and bottom plate this should bring it down to about negative 80 degrees Celsius this isn't as cold as I could get the copper if I had liquid nitrogen but dry ice I can pick up at my local grocery store if this works to slow my projectile down I'll know I can try some even more conductive materials and maybe have a better result but let's see what sort of difference it makes well I missed that shot and I got pretty lucky that my magnetic projectile didn't hit directly in the center of my camera lens but it landed safely under my workbench and I can try this again maybe with a little more accuracy that shot worked much better it went directly between the two plates unfortunately I'm still seeing sand pouring from my backstop so it obviously didn't slow down quite enough to not cause any damage it must have slowed down some because it's impossible for a magnetic field to pass by the copper without being offered some resistance but it's just not enough to slow it from the bullet like velocity I do think if I take this experiment one step further to the total extreme I can use the inductance of copper to stop a bullet but at this point it is completely ridiculous in a practical sense what I have here is a copper pipe this is eight feet long in 1 inch in diameter it's a common physics experiment or demonstration I should say to demonstrate the inductance of copper by dropping a magnet through the center of a copper pipe and showing how the magnet slows down as it passes through the pipe instead of falling through open air I did a similar experiment as this in my last video when I passed a magnet through a copper coil and showed how it produced electricity I'm pretty confident that this pipe is long enough to accomplish this task so much so that I don't have a backstop behind it so if it doesn't do its job I'll probably put a hole through the door of my barn once the cannon fires I'm gonna have to make a quick run back to the high speed camera back there to trigger the recording it records what it sees in a buffer so I actually need to hit the button for it to save what it is just seen and you got to be quick to do that especially when the camera is out there in the danger zone and I don't want to exactly be standing by the camera when this cannon fires well I heard the sound of a cannonball hitting something I have no idea if it was the side of the pipe because I probably didn't get the barrel of the cannon exactly lined up with this pipe that would have been really difficult to do or if it was the ball exiting the end and actually hitting something so I'm not sure if this worked or not yet I'm gonna have to wait and check the high-speed and see if the ball came out the end I'll use my magnet to check and see if I can feel where the Cannonball is in the pipe if it is indeed inside it is not inside okay so not even that worked well I guess there it is you can see that the Cannonball was still moving at a pretty significant speed by the time it exited the other end of the pipe so I think that solves it conclusively that copper is pretty well useless at slowing down a bullet like projectile this video was sponsored by audible which is a company that is completely unmatched when it comes to audiobooks they have an enormous selection more than anyone else and if you've ever purchased audiobooks through some other company before you've probably noticed that they're pretty expensive but not through audible and that is what I especially like about them through a really affordable subscription you get to choose a new book to add your collection every single month and these books are yours to listen to forever I've listened to tons of audio books through audible myself including the Martian which is one of my all-time favorites along with Robinson Crusoe and others and on the topic of this video the book wizard the life and times of Nikola Tesla Tesla lived a really interesting life and he is responsible for discovering much of what we know today about electricity and magnetism this book goes over his life and his discoveries in great detail you can get this book for free through a 30-day free trial to audible through a link I have in my video description below the link is audible.com forward slash Nighthawk that's ni GH tha wk audible.com /a Nighthawk check out audible through my link below I know you'll enjoy them because I have enjoyed audible myself for years I have nothing but good things to say this video only happened because so many of you left me comments and ideas in my previous video so please continue to do so on this video I would love to hear from you I still read all of my comments and it's a highlight of my day thank you so much for watching I'll see you next time

Channel: NightHawkInLight

Views: 3,616,889

Rating: 4.6583343 out of 5

Keywords: Magnets, Science, Experiment, Cannon, Electromagnet, Copper, Levitation, Levitate, Float, Tesla, Lenz, Faraday, Edison, Generator, Electricity, NightHawkInLight

Id: xUqbcpQqxhg

Length: 12min 50sec (770 seconds)

Published: Wed Feb 28 2018