Added: 1 year ago
From: sixtysymbols
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  • I want to do this with a superconductor...

  • Sounds like David Mitchell ^^

  • Oh my god, a fuse to limit the current going through that inductor... Come on, you guys can surely come up with a more elegant way of limiting the current...?

  • If I were you I would use a circuit breaker as opposed to fuses, it may cost a bit more to find one that will work for you but you will save money over buying fuses.

  • that was awesome

  • love the video man

  • great video thanks

  • I think that in a supercooled metal (superconductor) the current flows as a longitudinal wave...At least for me it makes more sens than the Cooper pairs electrons..

  • try copper?

  • Magnetic fields are cool, but the energy density in even our strongest magnetic fields is piddly compared to the energy in chemical bonds. Which is why the Professor's chemistry videos pwn everything else ;)

  • great video thanks

  • ok, last video. i need to sleep V_V

  • brilliant video

  • great video thanks

  • you have some great stuff here

  • "Electrical conductivity measuring device"

    lol

  • use a circuit breaker not fuses!!!

  • Good demonstration.

  • Try a copper ring!

  • Jesus and physics (L)

  • MAKE A RAIL GUN!

  • i met him , he came too my school

  • Huzzah for the XKCD shirt!

  • STAND BACK I AM GOING TO TRY SCIENCE

  • Why the fuck did it take so long to get this guy into some vids? He's obviously a badass.

  • Who is this guy? I'd never seen him before, he needs to do more vids!

  • xkcd t-shirt ftw!!

  • I WANT THAT T-SHIRT!

  • @DXR13KE Here you go. store.xkcd.com/

  • OMG! I just just found a long lost American hippie! and this one hasn't fried his brain with pot and LSD. wait ta sec, he looks faimilar. Was his dad in my polly si class?

  • @dufusrunescape "I just just found a long lost American hippie!"

    In fact, I think he and Richard Stallman are the only ones who show up at the reunions anymore. Richard's brain seems a little fried, but is still somewhat serviceable.

  • This is only possible because Aluminum is diamagnetic, i.e. it produces a weak, repulsive electromagnetic force. If he used something ferromagnetic like nickel or steel, it would just stick to the coil more aggressively.

  • @Desmaad

    Cool Story Bro.

  • Make a barrel and use a cylindrical projectile, placed just behind the middle of the coil. Will fly much better than any ring.

  • "To see... how far we can fling it."

    Thumbsup

  • I have the same T-Shirt :D

  • Rocking the XKCD shirt :P

  • "Stand back, i'm going to do SCIENCE!" Metalheads ARE the best :D

  • Oh hell no, is that an xkcd shirt...

  • The xkcd shirt made this all so much more fun. Have you tried a capaciter cannon?

  • I'm confused. There are more electrons passing through, that in turn gives more "push"? That doesn't make sense.

  • @formula406mpfi makes the magnetic field bigger?

  • what might be cool would be to see the aluminum again at a few hundred degrees C!

    that might be a bit of a fire hazard though...

    Still cool video!

  • @sixtysymbols Brady, how about inviting this guy for the clip again? He was both entertaining and educating.

  • get a hair cut.

  • @brenthoser99 nono his hair is cool!

    id tap dat. hahaha if he wasnt like 3 times my age.

  • why not charge a couple of 500 v 5000uf capacitors and a charging circuit you wouldn't have to to replace the fuse each time

  • use superconductor

  • *farther

    Not further

  • @adrastea99 thanks for that, you really made a difference in the world with your grammar corrections, oh what would we do without you...

    cheeky little fucker.

  • @hamfish225

    Hehehe

  • is he Jesus?

  • thats cold ..lol

  • I love the xkcd-shirt!

  • wow, i actually found the difference between the first and second shots really impressive and interesting. much more then i thought i would. its interesting that you use a single shot system, instead of building up in capacitors and firing from them.

  • As he's running, im thinking " He's not gunna try to pick that up with bare hands is he?" and sure enough, he does lol. He's lucky his hand didn't stick to it :P

  • HaHa, When he ran over i thought He's not going to be dumb enough to try to pick it up! But how wrong i was, lol.... Good vid shame about the frost bite!

  • Get the object of the demo clear in your head before you try to demonstrate ! All good but you have to be calm and explain what you are showing. The hair and beard don't translate well to other cultures. May be hip locally but in Asia you don't have any cred. Keep going but clean up your act. Good job. Prof. W. Bangkok

  • @frankin04 Gee, that's a shame, in our culture a scientist is judged by his contributions to science, not his appearance. i suppose then that Einstein's wild hair and moustache would have really thrown you for a loop, fortunately, the science community was able to look past his appearance and recognize the value of his theories .

  • @wendighoul: No need to drub the Prof for only telling the truth. Brady's films are targeted to YouTube, and are partially effective because everyone in them is at ease and casual. It appeals to young folks particularly because of it. No doubt the presenter would be more carefully dressed and prepared in almost any other venue than this one. The Prof is correct; in many cases presentation is almost as important as content; such silly animals we all are. Here it works; see others' comments.

  • @puncheex I stand by my statement. Prejudice based on appeareance is counter-productive. Anyone who would reject a valid idea because of the unkemptliness of its source may not deserve that knowledge in the first place, we are not punished for our prejudices, we are punished BY them. Just because society tends to value style over substance, does not mean it should be encouraged; quite the opposite, it should be challeneged at every opportunity.

  • @wendighoul: Nevertheless, it is a fact. I don't like religions, but they are a fact that I have to deal with. Having an ideal is great, as long as you don't loose reality in the pursuit.

  • i love how said so calmly "here's some liquid nitrogen"

  • @oscar2hot4u: It's not so surprising to have it around any more. My family physician in a suburb of Denver has it available in his office for skin lesion freezing and the like. Neat stuff to inspect in a foam cup close to hand.

  • @jacksawild

    Adding heat to the disk would give it more energy, thus causing the individual atoms in the lattice to vibrate more. Ultimately the disk would move hardly at all. Magnets are more repulsive at lower temperatures.

  • @18844lea: No - magnets operate at any temperature; they are basically unphased by their temperature; they operate on the sun, as well as very near abs zero. What the heat does is increase the resistance in the aluminum to an induced current; the opposing magnetic field's strength IS dependent on that current. All conductors that I'm aware of, outside of the superconducting realm, have resistance proportional to their temperatures, as discussed by the experimenter.

  • I'd like to see how far it goes if you get it red hot.

  • bdrlhjsorh.......JESUS IS HERE!!!!!!!!

  • This guy is just awesome!

  • As far as the gloves..?

    So precise.

  • xkcd shirt and metal hair is win

  • I love the xkcd shirt!

  • OMG! That guy looks like a young version of Richard Stallman!

  • That was awesome!

  • how much do one of those cannons cost

  • @UltimateFreerider the cannon is home built its really rather simple. it is about 500turns of heavy guage wire capable of 13A around a wooden former with a mains switch in series connected to a mains plug. there is a steel bar in the centre of the solenoid to focus the field but thats about it.

  • Sorry for posting again, but the YouTube kludge was giving me grief.

    At any rate, yes it seems that cooling the disc allowed conductivity to increase. However, I'd say it allowed it only momentarily. If increase current is sustained for a few seconds, thermal problems will ensue, canceling the effects of cooling. And certainly you'd want a hefty current sustained for long periods of time. But then Leidenfrost fight will ensue.

  • nice shirt beard man

  • You replaced the fuse to allow more current, no? That makes the disc go farther---more juice. It is not the cooling. It will shoot as far, even without cooling it.

  • @Austyg

    I think you may have misheard. From what I take it as, he replaced the fuse with the same one (13A). Basically it would draw too much current (100A), so by putting in a fuze that will break after one shot would allow them to use it without burning down the place.

    Please correct me if I'm wrong.

  • @br4nd0nh347 : Uh ... yes, indeed he does not explicitly say which fuse size is used the second time.

  • @Austyg

    well from the context it would seem so.

    He says," We use the fuses to stop the whole thing lighting on fire". This means more than one. Since only one fits in at a time I'm assuming all of the fuses are the same. I don't want to argue, I just wanted to point that out and of course there is a lot of research onthe web about this topic.

  • @br4nd0nh347

    Edit: Also the sentence before that he says," these fuses blow at 13A".

  • @br4nd0nh347  You are correct. I had a 13A fuse in the plug. This blows as soon as the current reaches 13A which is almost instantly after the switch is flicked. So between each shot I replace the fuse with another 13A fuse.

    Julian (from the video)

  • @Austyg: No. he was essentially plugging the electromagnet directly into the wall and allowing it to draw whatever current the wall could supply, which is well in excess of what the wires in the wall should carry (this is a dangerous thing to do, by the way). He used the fuse to shut the circuit off by burning out, and as far as we can tell it did the same thing in both experiments. The extra distance was due to the cooling of the ring, not the fuse operating differently.

  • @puncheex: Ah, I hear he used 13 amp fuses with a 15 amp service. Safe enough, as long as the fuse works reliably. However, it is obvious that the magnet wire won't handle 13 amps for any length of time. I don't imagine the UL (here in the US; don't know the UK equivalent) would be at all happy with that piece of apparatus.

  • @puncheex Every time you plug anything in to a socket you 'allow' it to draw whatever the 'wall' can supply. In the case of a short in any equipment, it may draw huge current, the 13 amp local fuse is there to protect the circuit after the fuse, the breaker in the distribution panel is there to protect the wires in the wall, the fuse on the mains supply is there to protect the incoming supply wires etc. there is nothing more inherently dangerous in this cannon than any other device.

  • @meucunt1: Ummmmm.... unless you have a sticky circuit breaker, and I've seen enough of those to know that a person who relies on it being there for him is a ways out on a limb. Personally, I'm a belt-and-suspenders sort of guy when it comes to fires.

  • Having a fuse in the plug is unheard of in North America.

    NZ (and regional Australia) has a lot of older dodgier EE practices still being permitted.

    NZ's older houses are famous for having the metering box inside the house -- a practice that vanished in the UK in the late 1950s.

  • Nice video and such a deliberately over the top way to demonstrate conductivity. I would have probably just done a four wire ohms test on a block of Al, which is not much fun at all.

  • Who else just knew that he was going to try and pick up the cold disc as he went bounding down the lab?

  • @defjam99b I was waiting for it too :)

    Reminds me of when I saw a guy on a moped with a noisy exhaust. When he was some way past me the exhaust actually fell off. Then he stopped, got off, walked back to the exhaust pipe and attempted to pick it up. Nasty.

  • slightly primitive ignition controller... but it works.

    Maybe go for something a wee bit more sophisticated?

    A charged capacitor?

  • i liked this guy, moar physics!

  • It's Science Jesus!

  • I love physics!!! Thanks for the video.

  • "So we've gone one, two, three, four, five... And a bit." Very scientific indeed...

  • Brady you should use alot more light for filming your slow motion footage... the high shutter speed requires alot more light then there was in the room. The footage was very noisy and grainy. Besides that nice work as always! and the cannon was cool!

  • @JaksProductions Your advice is so valuable as always, building on the few scraps I picked up during seven years at the BBC.

  • @sixtysymbols I know you worked for BBC, thats cool. And sorry if you misunderstood me, of course you know that you need proper light for a good video... I just told you that because you didnt seem to have them for this video.

  • @JaksProductions We had the room lighting, a plug in headlamp and 2 other directed lamps for that footage. Brady does know what he is doing.

  • @gobaskof I never said he doesent ;)

  • @sixtysymbols Nice reply :)

  • @sixtysymbols Now, three months later I feel like an ass because of the comment I wrote. Sorry Brad.

  • @sixtysymbols

    Another tip, don't use AC light sources with highspeed otherwise you'll record the flicker, use DC.

    A homemade LED lamp is cheap compared to studio lights and is much better, less power, less heat, very bright, no flicker.

  • @sixtysymbols I can't tell if that's sarcastic or not...

  • @JaksProductions You're one of those people who just can't help it, aren't you? You . . . "Your work is pretty good, but would have been much better if (blah, blah, blah)".

  • @twooonetwo Yeah, I guess so. And I knew brady had worked for BBC for a pretty long time. But he still made me feel like an idiot. :D

  • I like this

  • good explanation of super conductivity :p but try a coil gun

  • right right

  • wonderful.

  • Nice video. Where can I get one of those shirts?

  • neat

  • oooh, that was the most coherent explanation of the temperature/resistivity relation I have heard. Of course, its a phonon-electron interaction.

  • @PennyDorkis Thanks! Yeah, it would be nice to talk about phonons, but I was worried about being confusing. The idea that a vibration through a lattice can be treated as a particle which can scatter other particles is beautiful, but can take a while to get your head around. It would be great to do a video on photon photon scattering and umklapp processes to explain thermal conductivity. Not sure of a good demonstration though.

    Julian (from video)

  • Richard Matthew Stallman?

  • Is conductivity directly related to resistivity? I remember doing resistivity in A-Level physics.

  • @nolongerlong resistivity = 1/conductivity

  • @gobaskof ah - thought it's be something along those lines!

  • I dont know why but everytime i look at his beard i cringe.

  • He-hey never thought that Jesus was a phisicist, or a modern weapon designer.

  • The new jesus guy is awesome!

  • Nice experiment but the guy is less than clear and concise about the explanation.

  • You Guys are Great!

    Not so much a demonstration of Conductivity but of how conductivity changes vs temperature. Note this only works with Paramagnetic materials , Aluminium is the most practical material to use. Copper is heavier and Diamagnetic Electromagnetic rail guns, electromagnetic catapults on aircraft carriers and Mag-lev trains are other applications of the phenomenon.

  • @HarblesTheSkeptial Copper works, because it is the current induced producing the opposing field. There are also as you mentioned many other options to discus: impurities affect conductivity, semiconductors can conduct better at high temperatures, conductors vs. insulators.

    Another example too add to your list of applications is eddy current damping (used as breaks for roller coasters). There is a lot to talk about, and we can't do it all unfortunately.

    Julian (from video)

  • @gobaskof Fair enough. I do suppose it sounded more like criticism than embellishment.

    Carry on!

  • This was great :)

  • xkcd shirt! Also, your voice sounds like you're about to unveil a huge, evil superconductive Gauss cannon haha =)

  • "That's cold..." LOL! :D

    Like that guy.

  • xkcd shirt!

  • QFT "Stand back, I'm going to try sciences."

  • but auminum is A poor conductor try copper ring or peraps silver .

  • Comment removed

  • @wowggscrub the aluminium ring used has a conductivity of about 50% that of copper. we have tried a copper ring and the results were not as good. I think it has something to do with the time it takes for the fuse to blow something like a few mains cycles.

  • Superconductice . yesss

  • Thanks for making it so simple to understand :)

  • I wonder how far it would go at 0 kelvin

  • i would pay to see it at 100 amps

    could you use lots of power to brake it as it shoots it off the canon?

  • @mccutcheogeoff at 100A the coil would probably fling it's self apart or catch fire. it is only really rated at about 15A max

  • Dont give the army any funny ideas. Supercooler gaus cannons sound like trouble. ;)

  • lol he tried to pick it up!

  • Cool!!!!

    Love it when science uses magnets to shoot things :P

  • <3 Sixty Symbols

  • A guy on youtube uses large capacitors and launches old hard drive disks high up in the sky. No need to change fuses Same principal, but a better setup :-))

  • @insAneTunA got the vid title?

    or the v= ?

  • @SCARREDMIND

    I think that you don't understand what I am saying. Your comment makes no sense at all.I say that a guy on youtube uses large capacitors that he charges, after they are charged enough he flips a switch and the capacitors discharge to a flat coil. On top of the coil he has a hard drive disc that is aluminum with a coating. The disc is launched at high speed. He does not have to change fuses with that setup. Same principal, better setup.

  • Coincidence. My physics teacher just did this today.

  • i dont know what i would do if you guys stopped making this vids. I love them

  • Accent? Long hair? Beard? Xkcd shirt? Scientist? Dude, you are epic.

  • Is this how a railgun works?

  • @drosprey Similar physics (Electromagnetism), different set up. For a rail gun you have two rails connected to a voltage source, and your projectile completes the circuit. So you have a magnetic field from the current in the rails, and then the electrons in the rail move perpendicular to magnetic field. This causes something called a Lorentz force which accelerates the projectile along the rail. The reason a rail gun is so good is that it is accelerated all the way down the rail.

  • XKCD =D

  • XKCD shirt!  WOOO!

  • Excellent ! well done, my friend :)

  • Therefore it's the Electrons moving and these move the disc?

  • @Films4You There are electrons moving around the coil, this makes a magnetic field one way.

    The magnetic field makes electrons in the disk move the other way. Which produces a magnetic field in the opposite direction.

    We now have two magnets that repel, this is why it flies.

    The easier it is for the electrons to move in the disk, the stronger the magnetic field, and hence the further it flies.

    Julian (from the video)

  • @gobaskof Yes, A magnetic field repels a magnetic field in the disk.

    What I am tring to say is that this video indicates the electrons move, and push the disk away?

  • It's a UFO... LOL

  • XKCD shirt!

    This guy could be Magneto's apprentice. :)

  • i bet neil will have to get out the wall paint after your experiments :-)

  • Woo XKCD t-shirt :D

  • Cool!

  • Awesome experiment! The hair and beard is pretty kickass also.

  • Jesus!

  • USE A CIRCUIT BREAKER!. or a transistor to limit current.

    this wouldnt work with DC would it? only AC?

  • @rroge5 Yeah, I thought "Why can't they use a circuit breaker?", because fuses are the predececor of CB's.

  • @mantas1111000 indeed they are. but circuit breakers are also old fashioned lol. i would try to make some sort of current limited pulse controll cricuit using transistors.

  • @rroge5 Transistors?

    I haven't yet built a simple LED light.

  • @mantas1111000 yup,i believe a triac could effectivly turn on or off the power.

  • @mantas1111000 >> Would be better to use an SCR, a bank of capacitors and a diode in parallel+ resistor. 1) Charge capacitors to a high voltage (E=1/2 CV^2, note E goes as V^2) 2) Discharge capacitors through SCR (silicon controlled rectifier) 3) The coils reverse EMF and energy associated with it then discharges through a diode in series with a very low resistance, reasonably high powered resistor.

    All of this would need be be carefully designed to match the coil and component specifications

  • Comment removed