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Homemade Gauss Gun

bonzoesc writes: "I'm sure we all remember getting owned by some railgun-wielding kid in Quake2. Ever wanted a way to get back? Enter the Homemade Gauss Rifle. Requires wooden ruler with groove down the middle to serve as the rail, steel balls that can roll down the groove to use as projectiles, and magnets to store and redirect energy. Physics is fun!"

243 comments

  1. Team Fortress Classic by BrianGa · · Score: 3, Funny

    Do Doctors (Medics) get guns that are twice as fast as those given to us, the average Joe?

  2. That's not technically a gauss gun.. by Lotek · · Score: 0, Troll

    But it is still cool.

    1. Re:That's not technically a gauss gun.. by Anonymous Coward · · Score: 0

      That's not technically a gauss gun.. (Score:1, Flamebait)
      by Lotek (lotek&io,com) on Friday March 01, @10:30PM (#3096154)
      (User #29809 Info)


      Moderation: (-1, Stupid)

  3. First post! by supermoose · · Score: -1, Offtopic

    first post yay!

    1. Re:First post! by Super+Mario+Troll · · Score: -1

      Unfortunately, this is not the frist ps0t.

      WINNETKA, IL--A local man's ironic purchase of a humorously titled hardcore-porn video Saturday led to a sincere, earnest ejaculation devoid of any irony whatsoever.

      Josh Farmer
      According to reports, Josh Farmer, 27, accompanied by friends Brad Werner and Mike Tedesco, entered the Pine Street Adult Bookstore at approximately 3 p.m. to purchase an inflatable-woman doll as a light-hearted gift for friend Marshall Bloch, whose 23rd birthday party was to be celebrated later that evening at Farmer's house. While at the store, Farmer also purchased Terrors From The Clit, which he would later use as ejaculatory fodder in a wholly unironic session of vigorous masturbation.

      "Guys, check out this one," Farmer told Werner and Tedesco while browsing a row of videos. "Terrors From The Clit, starring Nikkie Love, Porsha and Intrusion! We should totally get this and make fun of it at the party. Wouldn't that be hilarious?"

      Continued Farmer, closely studying the photos of naked women engaging in graphic sex acts on the back of the box: "Dude, it's supposed to be a horror movie, except instead of all the chicks getting killed by the zombies, they have sex. Is that the dumbest thing ever?"

      After nearly 15 minutes of wisecrack-filled browsing, the men exited the store, having purchased a 'Lola Lungs' inflatable doll, a set of racy undergarments with which to festoon the doll, two packages of novelty glow-in-the-dark condoms and the ironic videotape.

      Above: The purchased videotape.
      Approximately 30 minutes before Bloch was due at the party, Farmer suggested to fellow partygoers that they have Terrors From The Clit playing when he arrived.

      "I forget Josh's exact words, but he basically was saying how it would be a sublime paradigmatic shift between Marshall's expectations and empiric reality if he walked into the party and saw us watching porn, as if that's what we normally do," Tedesco said. "Hence, you know, the irony. Get it?"

      Farmer's friends rejected his suggestion, telling him they would prefer to spend the remaining pre-party time preparing snacks. But Farmer did not give up, making several requests to view the tape during the actual party.

      "He kept saying, 'Dudes, we have to remember to watch that stupid video,'" Tedesco said. "So we finally gave in and watched the thing."

      Those present said Farmer watched Terrors "with great interest" from start to finish, deriving great ironic enjoyment from every scene.

      "He kept laughing and pointing out stuff in the movie, like how horrible the acting and music was, and saying stuff like, 'Oh, I'm so sure that would really happen!'" Werner said. "We were all just totally cracking jokes and making fun of it. But no one more than Josh: He was making smart-ass comments non-stop."

      At approximately 2 a.m., the party finally began to dissipate, and Bloch, gathering his gifts from the evening, reached for the Terrors videotape. According to witnesses, Farmer immediately stopped him, saying, "Wait, Marshall, you gotta let me borrow that. I have to show it to my brother when he's in town next week. He'll think it's so fucking hilarious."

      Bloch agreed, and minutes after the last guest left his apartment, Farmer put the video back into his VCR and hit play. Unfastening the zipper on his pants, Farmer watched the video and began stroking his penis without humorous intent. He achieved orgasm some 12 minutes into the viewing, ejaculating into his cupped left hand in a manner that neither inverted nor subverted any thematic paradigms.

      Despite Farmer's repeated insistence that his viewing of the tape was strictly ironic, most experts familiar with the case are unconvinced.

      "It appears that Mr. Farmer, despite his derisive stance toward Terrors From The Clit while in the adult bookstore, ultimately enjoyed it in a wholly sincere and heartfelt manner," said Georgetown University sociology professor Dr. William Campos. "He was somehow able to derive genuine entertainment from a most unlikely and counterintuitive source--a video so distasteful and poorly executed that he purchased it specifically to mock it."

      "For all his initial misgivings, Josh managed to overcome his ironic stance and simply enjoy the thrusting, grunting performances on their own merits," Campos said. "How he did it, we do not yet know. But I am definitely going to need to borrow this tape for research purposes. Perhaps through the exhaustive eye of scientific scrutiny, I believe we can get to the truth at the heart of this mystery.

      --

      Goat: It's what's for dinner!

  4. Win2K and the SAK Offser Superior Value Over Linux by RoboTroll · · Score: -1
    This white paper describes the complete appliance solution of Windows 2000 and the Microsoft Server Appliance Kit 2.0. The paper also describes seven key benefits to OEMs that use Windows 2000 and the SAK 2.0 over similar Linux-based solutions.

    SummaryThe Windows 2000 appliance solution offers OEMs industry-leading performance and scalability, high availability, and data protection. Appliances powered with Windows are also customized and pre-configured for a specific function such as file serving or Web content serving, allowing for fast and simple deployment. Therefore, these appliances based on Windows 2000 offer both OEMS and their customers superior value when compared with similar Linux-based solutions.

    Specifically, Windows 2000 and the Microsoft Server Appliance Kit 2.0 provide a range of benefits for their customers. Benefits include:

    =Faster time to market
    =Ease of deployment and administration
    =Interoperability across multiple network =operating systems
    =Lower cost of ownership and development
    =Clarity of intellectual property ownership
    =Predictability of the development process

    From the annals of the Troll Library .

  5. See my vest by Anonymous Coward · · Score: -1, Offtopic

    See my vest, see my vest, made from real gorilla chest.

    1. Re:See my vest by supermoose · · Score: 1, Funny

      See my loafers, former gophers. See my hat... 'twas my cat.

    2. Re:See my vest by Anonymous Coward · · Score: -1, Troll

      See my socks, see my socks, made with the cocks of former jocks.

      graspee

  6. oooh, fun! by Spaceman+Spiff+II · · Score: 1

    Now I wonder if he has any patents pending. I could make it portable and market it and make millions. Seriously, though, I think I'm going to have to try this. Maybe we could do something fun like this in physics. I know it's always boring for me.. :(

    --
    I understand that life's not fair, just why is it never unfair in my favor?
    1. Re:oooh, fun! by Joe+Decker · · Score: 1
      I doubt there's any patents pending, but I do notice that he'll sell you some of the hard-to-find parts, e.g., appropriately shaped magnets, etc.

      His Film Can Cannon is pretty darn cool, too.

  7. Games for Physicists? by citroidSD · · Score: 5, Funny

    I knew this would happen. First you had Physics for Game Developers Now you have Game Weapons for Physicists.

    Sigh, what's next, perpetual motion?

    1. Re:Games for Physicists? by dimator · · Score: 2

      Sigh, what's next, perpetual motion?

      In this house, we obey the laws of thermodynamics!

      --
      python -c "x='python -c %sx=%s; print x%%(chr(34),repr(x),chr(34))%s'; print x%(chr(34),repr(x),chr(34))"
    2. Re:Games for Physicists? by batobin · · Score: 1

      Helpful hint: copy the URL of that .wav and paste it into a new window to avoid Angelfire's stupid "no outside link" policy".

  8. Why can't we advance things like this? by prof187 · · Score: 0, Troll

    We can make something this simple, so why can't we make some kind of "ideal machine" similarly? I know that calling it an ideal machine is wrong, but that's the closest I can get to it. Why not use a similar setup, only circular, to make something that can generate electricity with only a push needed to start it. After that it could not only support itself with the power it produces, but make excess and actually power something. I know that things like this (motors) are already made, but for as much as I can remember, not to this extent.

    --

    My other sig is an import.
    1. Re:Why can't we advance things like this? by ForceOfWill · · Score: 2, Informative

      Read the article, especially the part labelled "Why a circular track will not be a perpetual motion device"

      --

      --
      Seeing is believing; You wouldn't have seen it if you didn't believe it.
    2. Re:Why can't we advance things like this? by UU7 · · Score: 1

      Perpetual motion eh ?

      Yup, that's what we need..
      perhaps then /. could lower their power bill and get rid of the subscriptions.

      mmm hmm

    3. Re:Why can't we advance things like this? by prof187 · · Score: 1

      I did, but I'm talking about using a push to get it started and then letting it power itself with a current. The article is talking about unpowered motion which can't happen because of different parts of physics, the whole energy lost to heat deal, blah blah...

      --

      My other sig is an import.
    4. Re:Why can't we advance things like this? by prof187 · · Score: 0, Offtopic

      >perhaps then /. could lower their power bill and get rid of the subscriptions.

      hehe...

      --

      My other sig is an import.
    5. Re:Why can't we advance things like this? by RMSIsAnIdiot · · Score: 0

      "In this house we obey the laws of thermodynamics!"

      -Homer J. Simpson

      --

    6. Re:Why can't we advance things like this? by Anonymous Coward · · Score: 0

      A better solution would be to convert the heat from CowboyMeal and CommanderTaco to electricity. I bet those two combined could power a few servers.

    7. Re:Why can't we advance things like this? by Anonymous Coward · · Score: 0
      It doesn't matter whether it "powers itself with a current"; you can't evade the laws of thermodynamics. Whatever power it pumps back into itself will be less than the initial power provided, since there will be heat loss, and the thing will run down when all the energy in the system is exhausted.


      (Reminds me of when I was a kid and I had the "brilliant" idea of a perpetual-motion submarine, whose propellor spun a generator that powered the propellor...)

    8. Re:Why can't we advance things like this? by parnasus · · Score: 2, Informative

      The heat loss due to friction is enough to bring this "perpetual motion" machine to a halt. There is no way in the universe to convert from one form of energy into another without some loss to heat.

      --
      --If you code for the exceptions, the rules fall into place
  9. Perhaps... by Beowulf_Boy · · Score: 1

    Make this in a tube, so that you could flex it to aim, you could shoot around corners, and just increase the length of your tubeing (and magnets) for a stronger gun.

    1. Re:Perhaps... by Anonymous Coward · · Score: 0

      I think the ball touching the magnet stays touching the magnet. If this were in a tube, it would be really hard to "reset."

    2. Re:Perhaps... by Anonymous Coward · · Score: 0

      Couldn't you turn the tube around?

    3. Re:Perhaps... by lingon · · Score: 1

      Well, no, because the balls would stick to the magnets

    4. Re:Perhaps... by Anonymous Coward · · Score: 0

      The problem with tubes, or any kind of non-linear motion is most likely the friction generated by the balls rubbing against whatever is used to turn them. You know it won't work, because it even sounds painful.

  10. Lies. by whee · · Score: 5, Funny
    This is obviously a fake railgun; It lacks the spiral of blue particles that lead back to the source. Nice try, though.

    (At least this isn't a homemade BFG -- I'd be really scared then)

    1. Re:Lies. by G-funk · · Score: 2

      When I first read "gauss gun" I thought it was instructions for a rocket launcher. Too much syndicate for me!

      --
      Send lawyers, guns, and money!
    2. Re:Lies. by Anonymous Coward · · Score: 0

      A 'gauss gun' has always been a 'rail gun', in all kinds of game genres over the years. What kind of fucked up thing is syndicate?

    3. Re:Lies. by bonzoesc · · Score: 2, Funny

      Dip the steel ball on the end in blue paint before firing. Pretend that the mess on the floor is a spiral. I don't have the ball bearings handy in my dorm room to try this out, but I think you might need to make your own "PIIIIUUUU" sound effect, too.

  11. Thanks, Americans! by Anonymous Coward · · Score: -1, Troll

    I sent a copy of this article to my Al Qaeda friends; I'm sure you'll be hearing of their success in short order!

    1. Re:Thanks, Americans! by negativekarmanow+tm · · Score: 0

      Yeah just like when some news agency reported Al Qaeda had the blueprints for making atomic bombs.

      --
      No security through obscurity: my password is goatse. Stop me before I troll again.
  12. Hmm by FakePlasticDubya · · Score: 3, Funny

    "But officer, you see, it's for my electrophysics class."

    --

    "We shall show mercy, but we shall not ask for it" -- Winston Churchill
    1. Re:Hmm by Mayor+McPenisman · · Score: -1

      you are dumb.

      Thank you for your time.

      --
      [[Ay fukkand lyke ane furious Fornicatour]]
  13. Basically . . . . by OverlordQ · · Score: 1

    It does to 'large' objects what a Particle Accelerator does to particles.

    --
    Your hair look like poop, Bob! - Wanker.
    1. Re:Basically . . . . by MoogMan · · Score: 1

      I think a particle accelerator has a slightly different configuration of magnets. First off they are electromagnets pulsing on and off in syncs with a passing particle and secondly, they are wrapped around the particle accelerator 'pipe' (heh I doubt if that is the technical term for it)...
      Hmm, I guess someone has already made a real 'Large Accelerator' shall we call it ;)
      Anyone got any links for this? Otherwise im gonna have to make my own :D

    2. Re:Basically . . . . by psyco484 · · Score: 0

      leave it to someone on slashdot to take a relativly simple device and make an analogy to a particle accelerator...

  14. Oh yeah? by Sarlok · · Score: -1, Offtopic

    I can still break windows faster with my mighty printf!

    main(){while(printf("\t\b\b\b"));}

    Suck on THAT Bill!

  15. His desire by inerte · · Score: 0, Offtopic

    He sure wanted to have Gausswith!

    587kb, still loading, slooooooooow, and counting!

  16. Degaussing gun by mcc · · Score: 5, Funny

    Eh.. i'm disappointed. I initially misread that as "degauss rifle"..

    After discovering in computer labs that hitting the "deguass" button on a monitor will cause the monitors nearby to trip out very slightly for an instant, i had these vague daydreams of rewiring whatever it is in the monitor that makes it deguass to be unreasonably strong, so that hitting "deguass" would cause the monitors of all the computers in the lab or whatever else is in a 40-foot radius to be degaussed at once, Matrix EMP-blast style. This would probably break stuff, but then that's the point, i suppose.

    I dunno.. i guess having instructions on how to build a mini-rail-gun really is much cooler, but still, i wonder if the guass-blast idea is possible.. and if it were, modifying the idea to create a gun you could stick at a monitor and pull the trigger to deguass it would be really funny. Alas, there's no practical use for such a thing as far as i can tell, and it isn't really *that* interesting, so i don't really care enough to do any research on the subject, so for now, it looks like i'm going to have to limit myself to putting an electric pencil sharpener next to the monitor, sticking in pencils, and giggling.

    1. Re:Degaussing gun by Anonymous Coward · · Score: 2, Informative

      GO get you one of those Nifty Radio Shack degaussing "Irons" for cleanign disk and tapes
      the will do a number on a monitor at about 5 feet.
      It's nifty to look at if your into that kind of thing.

    2. Re:Degaussing gun by PhuCknuT · · Score: 5, Informative

      What makes the monitor degauss is just a coil of wire around the edge of the screen, that has an alternating current put through it to create an alternating magnetic field. The field it creates doesn't need to extend very far, since it's wound directly around the screen.

      If you hooked up a stronger power supply to the degauss coil, you could probably degauss a couple monitors at once, but the coil would burn out quickly.

      Interesting trick though, if you ever have a monitor or tv that needs to be degaussed, that doesn't have it's own degauss coil. Hold it face to face with a monitor with a degausser, and hit the button, it will degauss them both at once.

    3. Re:Degaussing gun by nzhavok · · Score: 3

      so that hitting "deguass" would cause the monitors of all the computers in the lab or whatever else is in a 40-foot radius to be degaussed at once, Matrix EMP-blast style

      Well I suppose you could create some massive degausser, and it would work as long as you don't mind destroying your hard drives at the same time. Mabye you could try coupling a "bulk eraser" with some massive power supply...

      --

      He who defends everything, defends nothing. -- Fredrick The Great
    4. Re:Degaussing gun by SgtXaos · · Score: 5, Interesting

      The navy has a degaussing station near Norfolk Naval base (and probably others near big bases). They use it to degauss entire ships. The ships, being predominately steel, pick up residual magnetic fields from sailing though the earth's magnetic field. They need to periodically remove these residual fields. They float the ship in, then connect big cables over top of the vessel, and send big currents through the coils. Not sure how it affects internal equipment, but I suppose that the hull shields most of it the same way the shielding in your computer speakers prevents the voice coil magnets from screwing up your monitor.
      If you have an old color monitor you don't care about, put a magnet near the screen sometime. (ooh, a rainbow!) As this falls in the same category of fun as microwaving CDs, don't expect the degaussing circuits to fix the result anytime soon. in other words, don't do this to a monitor you wanna use.

      --
      -- Don't call me "Sir," I increase entropy for a living!
    5. Re:Degaussing gun by Tetrad69 · · Score: 2, Interesting

      I'm not sure if this is true or not, but I heard you could manually degauss monitors with a magnet by going in circular motions from the center and working your way outward.

      So if you have an old color monitor that's messed up, you just may be able to fix it. Of course, keep the magnets away from your RAID 0+1 array...

    6. Re:Degaussing gun by ahaning · · Score: 1

      I wish my Physics class entitled "Electricity and Magnetism" had been de-Gauss'ed.

      (As well, I wish my Calculus course could be de-Calculus'ed.)

      --
      Withdrawal before climax is very ineffective and those who try this are usually called "parents."
    7. Re:Degaussing gun by ErfC · · Score: 2
      ...don't do this to a monitor you wanna use.

      Around TRIUMF, where I work, we have a lot of monitors get "gaussed" by the cyclotron's magnetic field. Most monitors around there have some pretty rainbow effects. Turns out that the degauss button available on the newer ones works pretty well to fix them.

      I'd still suggest not doing this deliberately, but if it happens there's at least hope of recovery.

      --

      -Erf C.
      Cthulu always calls collect...

    8. Re:Degaussing gun by Anonymous Coward · · Score: 0

      I always involuntarily shiver when I'm near a monitor that is degaussing. I take it as evidence that humans DO have a low-frequency E.M. sense.

    9. Re:Degaussing gun by jlower · · Score: 1

      All you young pups wouldn't know but in the early days of color television you would have a repairman come to the house occasionally and wave this big magnetic hoop around the outside of your set to degauss it.

      Of course, about the only things that were actually broadcast in color were commercials, but hey - it was still cool.

    10. Re:Degaussing gun by MarkoNo5 · · Score: 1

      Well, actually I've got a degauss canon. It's called Iiyama Visionmaster PRO 510. Once when I switched on my monitor, a friend of mine asked on irc whether I had turned on my screen. He heard the bang, being 30 meters aways in another building.

      Not really a weapon, but you can scare the sh*t out of people who've never heard it before :)

      Marko No. 5

    11. Re:Degaussing gun by birdman042 · · Score: 0, Flamebait

      On my last ship we had degaussing equipment inside the skin of the ship. Unfortunately there was a cable run in my "office" I couldn't count the number of times I would be playing something (SOF, QIII, UT, Deus Ex, System Shock2,etc) and have the equipment really screw up my monitor. (Mind you this was my personal PC as I had a couple of friends in the IT department) I never left the 'puter running if I was out of the office (which was a lot.. as many of nights getting off of watch and spending a couple of hours chasing mutant monkeys with a wrench...) as there would be a nice color display pattern waiting for me when I got back. I think I used the degaussing button more often than the power button....

    12. Re:Degaussing gun by bubblegoose · · Score: 2, Informative

      I've been through the one at Norfolk, we spent a day offloading sensitive electronic gear. Mostly the 4 or 5 PCs on board, weapons and sonar screens. Most of the electricial equipment on Navy ships are of an old design and wouldn't be affected by this. The Navy believes if it is less than 20 years old it must be some new-fangled stuff and not tested enough for their liking.

      --
      I hope that someday we will be able to put away our fears and prejudices and just laugh at people. - Jack Handey
    13. Re:Degaussing gun by Marsell · · Score: 1

      Actually, you _can_ fix a monitor after holding a magnet to it. Where I used to work we'd just hold the side of a gun-type soldering iron to the screen face and circle it a couple of times.

      I guess you're bored when you place magnets on screens to see the pretty colors, then fix them up afterwards before returning them to customers. :-)

      .

    14. Re:Degaussing gun by Yarn · · Score: 2

      I used to work at a hospital, near the MRI. The huge field from this thing did... interesting things to monitors. Generally we got iiyamas because they were slightly more resistant than the other makes, but the build in degaussing coil was never up to the job. One of the technicians had a high current transformer and a frame with thick copper wire wrapped round it to degauss manually.

      Computers especially close to the magnet had to be housed in a special steel alloy, referred to as 'mu' metal.

      We once got one mac, for some training software. The monitor it came with went 30 degrees sideways permanently...

      --
      -Yarn - Rio Karma: Excellent
  17. Background information . . . by OverlordQ · · Score: 5, Informative

    . . . about 'Gauss Guns' can be found here

    --
    Your hair look like poop, Bob! - Wanker.
    1. Re:Background information . . . by Anonymous Coward · · Score: 0

      Mod this down -1: Boring.

  18. Uhh... by AnalogBoy · · Score: 5, Funny

    you didn't just give a bunch of undersexed, over hormonal, arrogant teenagers instructions on how to build a DANGEROUS WEAPON, now, did you?

    -ugh-

    :)

    1. Re:Uhh... by Anonymous Coward · · Score: 0

      Um who cares? They can get them at their local gun shows without going to the trouble of building them. Ref: Columbine.

    2. Re:Uhh... by Lectrik · · Score: 1

      Oh No!
      don't give teenagers (and/or nerds) science, cuz then the terrorist win. we must pass a vauge law to prevent any future occurance and then another one to require that some hardware be installed to prevent anyone from breaking our original vauge law.

      --
      --- As to make my comment seem, by comparison, more intelegent... doodie doodie doodie poop poop poop!
    3. Re:Uhh... by data888 · · Score: 1

      Hopefully the teens you speak of don't read Slashdot, or come Monday morning there's gonna be a linear induction arms race between the geeks and jocks.

      Nick Taylor

      --
      ----------------------------- Currently serving a 13 year sentence at juvenile "education" centre.
    4. Re:Uhh... by Anonymous Coward · · Score: 0

      Intruder alert!
      Stop the humanoid!

  19. Does anyone have a mirror? by xX_sticky_Xx · · Score: 1

    I finally got the page loaded but the images are all broken. Archive.org and Google don't seem to have it cached.

    --

    ---

    I didn't want to leave this space blank.
    1. Re:Does anyone have a mirror? by Barbarian · · Score: 2

      Mirror please, this is important stuff!

    2. Re:Does anyone have a mirror? by Matrim9 · · Score: 1

      A few of the more impressive pictures: http://spiff.homelinux.net/gaussgun/

    3. Re:Does anyone have a mirror? by DJPenguin · · Score: 1

      Why are slashdot readers so vain? Always asking for mirrors!! :)

    4. Re:Does anyone have a mirror? by Anonymous Coward · · Score: 0

      LOL that's rather funny! :-)

  20. good idea? by abdulla · · Score: 0

    why does it not seem like a good idea to me? maybe i'm just getting to old, worrying about steel balls being lodged in my head, oh well!

  21. What I really want.. by krogoth · · Score: 0, Offtopic

    Is a home-made slashdotter. Nothing hurts like getting linked to from the /. frontpage.

    --

    They that quote Benjamin Franklin on liberty and safety deserve neither.
  22. In case of /. effect by beefstu01 · · Score: 3, Informative

    I guess this is just too damn good to pass up to be waiting for a slashdotted site to load... no pictures, but here's the text.. should satisfy your needs. Enjoy!

    Experimenting with magnetorheological fluids.
    Suspending a magnet in mid-air.
    Levitating pyrolytic graphite.
    A Gauss Rifle: A Magnetic Linear Accelerator.
    Building a Curie-effect heat engine.
    Going further:

    Superconductors.

    The Gauss Rifle:
    A Magnetic Linear Accelerator

    This very simple toy uses a magnetic chain reaction to launch a steel marble at a target at high speed. The toy is very simple to build, going together in minutes, and is very simple to understand and explain, and yet fascinating to watch and to use.

    The photo above shows six frames of video showing this toy in action. Each frame shows 1/30th of a second. In the first frame, a steel ball starts rolling towards a magnet taped to a wooden ruler. In the second frame, a second ball can be seen speeding between the rightmost two magnets. By the third frame, the accelerator has sped up so much that the ball that is seen leaving the left side of the device is just a blur as it smashes into the target. One ball, starting at rest, has caused another ball to leave the device at a very high speed.

    The materials are simple. We need a wooden ruler that has a groove in the top in which a steel ball can roll easily. Any piece of wood or aluminum or brass with a groove will work. We chose the ruler because they are easy to find around the house or at school or at a local stationery store.

    We need some sticky tape. Again, almost any kind will do. Here we use Scotch brand transparent tape, but vinyl electrical tape works just as well.

    We need four magnets. Most any type will do, but the stronger the magnets are, the faster the balls will go. Here we use the super strong gold-plated neodymium-iron-boron magnets we have made available in our catalog for the other projects. They work great.

    We will also need nine steel balls, with a diameter that is a close match to the height of the magnets. We use 5/8 inch diameter nickel plated steel balls from our catalog.

    The only tool we will need is a sharp knife for trimming the tape.

    We start by taping the first magnet to the ruler at the 2.5 inch mark. The distance is somewhat arbitrary -- we wanted to get all four magnets on a one foot ruler. Feel free to experiment with the spacing later.

    With the sharp knife, trim off any excess tape. Be careful, since the knife will be strongly attracted to the magnet.

    It is very important that you keep the magnets from jumping together. They are made of a brittle sintered material that shatters like a ceramic. Tape the ruler to the table temporarily, so that it doesn't jump up to the next magnet as you tape the second magnet to the ruler.

    Continue taping the magnets to the ruler, leaving 2.5 inches between the magnets.

    When all four magnets are taped to the ruler, it is time to load the device with the balls.

    To the right of each magnet, place two steel balls. Arrange a target to the right of the device, so the ball does not roll down the street and get lost.

    To fire the gun, set a steel ball in the groove to the left of the leftmost magnet. Let the ball go. If it is close enough to the magnet, it will start rolling by itself, and hit the magnet.

    When the gun fires, it will happen too fast to see. The ball on the right will shoot away from the gun, and hit the target with considerable force. Our one foot long version is designed so the speed is not enough to hurt someone, and you can use your hand or foot as a target.

    How does it do that?

    When you release the first ball, it is attracted to the first magnet. It hits the magnet with a respectable amount of force, and a kinetic energy we will call "1 unit".

    The kinetic energy of the ball is transfered to the magnet, and then to the ball that is touching it on the right, and then to the ball that is touching that one. This transfer of kinetic energy is familiar to billiards players -- when the cue ball hits another ball, the cue ball stops and the other ball speeds off.

    The third ball is now moving with a kinetic energy of 1 unit. But it is moving towards the second magnet. It picks up speed as the second magnet pulls it closer. When it hits the second magnet, it is moving nearly twice as fast as the first ball.

    The third ball hits the magnet, and the fifth ball starts to move with a kinetic energy of 2 units. It speeds up as it nears the third magnet, and hits with of 3 units of kinetic energy. This causes the seventh ball to speed off towards the last magnet. As it gets drawn to the last magnet, it speeds up to 4 units of kinetic energy.

    The kinetic energy is now transfered to the last ball, which speeds off at 4 units, to hit the target.

    When the device is all set up and ready to be triggered, we can see that there are four balls that are touching their magnets. These balls are at what physicists call the "ground state". It takes energy to move them away from the magnets.

    But each of these balls has another ball touching it. These second balls are not at the ground state. They are each 5/8ths of an inch from a magnet. They are easier to move than the balls that are touching the magnet.

    If we were to take a ball that was touching a magnet, and pull it away from the magnet until it was 5/8ths of an inch away, we would be adding energy to the ball. The ball would be pulling towards the magnet with some considerable force. We could get the energy back by letting the ball go.

    After the gun has fired, the situation is different. Now each of the balls is touching a magnet. There is one ball on each side of each magnet. Each ball is in its ground state, and has given up the energy that was stored by being 5/8ths of an inch from a magnet. That energy has gone into the last ball, which uses it to destroy the target.

    Speed and kinetic energy

    The kinetic energy of an object is defined as its mass times the square of its velocity. As each magnet pulls on a ball, it adds kinetic energy to the ball linearly.

    But the speed does not add up linearly. If we have 4 magnets, the kinetic energy is 4, but the speed goes up as the square root of the kinetic energy. As we add more magnets, the speed goes up by a smaller amount each time. But the distance the ball will roll, and the damage it causes to what it hits, is a function of the kinetic energy, and thus a function of how many magnets we use.

    We can keep scaling up the gun until the kinetic energy gets so high that the last magnet is shattered by the impact. After that, adding more magnets will not do much good.

    Why a circular track will not be a perpetual motion device

    I have been getting a lot of mail asking what would happen if we made the track circular. Would we get free energy? Would the balls keep accelerating forever?

    I have been tempted to reply with the famous quote: "There are two kinds of people in the world -- those who understand the second law of thermodynamics, and those who don't".

    However, I am not the kind of person to leave an inquiring mind unsatisfied, and it is more productive (and kind) to explain in a little more depth what is going on.

    Suppose you made a circular track, and put two balls after each magnet. When the last ball is released, it encounters a magnet that has two balls at the ground state. There is no energy to be had from this magnet. The ball just bounces back.

    Now suppose you had placed three balls after each magnet. When the last ball is released, it hits a ball that is 5/8ths inch from the magnet. It has not gained much momentum, because most of the momentum gained is in the last half inch as the magnet pulls much stronger on things that are closer. But the ball has enough energy from previous accelerations to release the next ball. However, that ball has less energy than the ball that caused it to release. It may have enough energy to release another ball or two, but each ball that is released has less energy than before, and eventually the chain stops.

    You can show by inductive logic that no matter how many balls you stack in front of each magnet, eventually the system stops.

    To estimate the losses due to heating the balls as they compress when hit, consider a plastic tube standing upright on a table. Place one steel ball at the bottom of the tube. Now drop another ball into the tube, so it hits the ball at the bottom, and bounces back up.

    Now measure how high the ball bounced. If it bounces halfway back up, the losses are 50%. Perform the experiment for yourself with the balls from the Gauss Rifle. How high does your ball bounce? Send me mail with your results.

  23. What the fuck does it link to? by Anonymous Coward · · Score: -1, Flamebait


    404 dude.

    SLASHWIFE
    News for niggers. Stuff for darkies.

    WATERMELON UNDER THE GPL

    POPEYES SELLING CUSTOMER DATA

    BREW YOUR OWN 40s OR STEAL THEM

    PORCH SITTING PIONEER DEAD AT 54

    BOOK REVIEW: READ? FUCK DAT!

    ASK SLASHWIFE: GOOD CRACK FOR CHEAP?

    YOUR RIGHTS ON WELFARE: BUYING SMOKES WITH FOODSTAMPS

    DNA TESTING NARROWS THE FATHER DOWN TO 1 IN 150

  24. Some one had to say it..... by Rebel+Patriot · · Score: 0, Offtopic

    Imagine a Beowulf cluster of these.....

    ::ducks to avoid the many groans and insults::

    --
    Slackware forever. Honestly, what else would you trust when it absolutely positively has to be stable, secure, and easy
  25. I don't get this by rangek · · Score: 0

    They say

    It is very important that you keep the magnets from jumping together. They are made of a brittle sintered material that shatters like a ceramic.

    But the gun works by repeatedly smashing these same delicate magnets with steel balls! If the magnets are really so fragile, wouldn't they break?

    1. Re:I don't get this by xX_sticky_Xx · · Score: 2

      If you read to near the end of the article it states that scaling the fun up past a certain degree would indeed cause the end magnets to shatter. The force of two of the magnets coming together is larger than that of one of the little ball bearings hitting one of them. Neodymium magnets will easily shatter if you drop them on the floor as well.

      --

      ---

      I didn't want to leave this space blank.
  26. Other Fun Ideas by Eddy+Johnson · · Score: 0

    - Now that /.ers have built Quake weaponary, we must also figure out how to build the plasma rifle from the DOOM series. Maybe construct a set of modded paintballs with mini-light sticks in them to make them glow blue until they hit you, and it'll look just as cool.

    - Check out the schems for the stun guns on howstuffworks.com and sodder it together instead of wasting your time with the circuit boards. Put it into a case in your jacket pocket and wire the contacts through the lining and down your sleeve. Wear a leather glove with the studded knuckles and hook them up (carefully, lest you zap yourself instead) to the metal studded knuckles. BRZAP - knocks 'em out with one punch. This is a lesson on How To Get That Amazingly Powerful Killing Punch From First-Person Shooters.

    What fun geeks really have! WOO!

    --


    Anonymous Coward: (n.) 1. nerd at school or library. 2. karmawhore in training. 3. embarrased prep.
    1. Re:Other Fun Ideas by dotderf · · Score: 1

      Glow in the dark paintball do exist. My friends have used them for night games. Unfortunately, they're prohibitively expensive. Make spiffy tracer rounds, though!

    2. Re:Other Fun Ideas by Mayor+McPenisman · · Score: -1

      You have dumb in the head. Check your brain pan for problems, maybe scarring, blood clots, or rotten flesh. Please notify us as these problems are solved, I really care about you!

      poop.

      --
      [[Ay fukkand lyke ane furious Fornicatour]]
    3. Re:Other Fun Ideas by Graymalkin · · Score: 3, Insightful

      A while back in G&A I think I saw an article about stun gloves which took the components of a stun gun and housed them inside a leather glove. You pressed down on a trigger and the electrodes were in the cuff of your hand between your index finger and thumb. All you had to do was grab somebody and they were in for a shock.

      --
      I'm a loner Dottie, a Rebel.
  27. Hehe by xX_sticky_Xx · · Score: 2

    That should be "scaling the gun up past a certain degree", although "fun" works too.

    The 2 minute posting rule sure does suck.

    --

    ---

    I didn't want to leave this space blank.
  28. The Magical Anal Raping Bear!!! by Super+Mario+Troll · · Score: -1

    This troll was shamelessly ripped from the Onion (http://www.theonion.com). If this offends you, I suggest filing a complaint at http://goatse.cx.

    Here's a little dog-bites-man tale we couldn't resist! Except replace "dog" with "850-pound black bear"! And "bites" with "anally violate"!

    Grin and bear it! Barry, an 850 lb. black bear, got a little frisky with zookeeper Ron Gilks. The anal rape is believed to be the first inter-special coupling in Metro Zoo history.
    Yes, last Saturday a zookeeper at the Metropolitan Zoo had "claws" for alarm when he was attacked and raped by the same black bear he had raised from a cub! Geez, talk about gratitude!

    "It was horrible, just horrible," sobbed an eyewitness. Guess she sure got an eyeful!

    The bear, named "Barry," attacked zookeeper Ron Gilks as Gilks entered the cage to give him dinner. Barry lunged at his throat, goring him with his huge claws and razor-sharp teeth. Some of the claw marks were three-quarters of an inch deep. Ouch!

    Then, astonished onlookers could "bearly" believe what happened next--Barry began to brutally rape zookeeper Gilks!

    Frantic zookeepers rushed for rifles as others tried to divert the bear. But there was no stopping Barry! This bear kept "bearing down," and Gilks just had to grin and "bear" it! Maybe Barry was mistaking him for his "honey"!

    Gilks was pronounced dead upon arrival at the hospital. A full quart of bear semen was extracted from his ruptured chest cavity. And that's no small Boo-Boo!
    Barry's 27-inch phallus, armed with guard hairs as sharp as red-hot needles, shot through Gilks' rectum, shattered his lower spine and skewered his colon, causing his entire lower torso to "cave" in! Yikes! Bet that wasn't the type of "cave" you had in mind when you took up zookeeping, Mr. Gilks!

    And can you imagine Gilks' surprise when Barry's putrid ursine semen flooded his ruptured chest cavity? (By the way, Mr. Gilks, whatever cologne you've been wearing, where can the public get some?)

    Finally, zookeeper Eric Pulliam shot Barry with a tranquilizer gun and pulled Gilks from the cage. The unconscious bear was later destroyed. Hey, this "Yogi" made a major "Boo-Boo"!

    "I have worked with dangerous animals before," zoo director Kate Donegal said. "But never have I seen any animal sexually assault a human being." "Barry"? Try "Scary"!

    Meanwhile, Gilks was pronounced dead at an area hospital--but at least he died grinning and bearing it! No doubt, this episode gives new meaning to the term, "Do not feed the bears!"

    Here's a little dog-bites-man tale we couldn't resist! Except replace "dog" with "850-pound black bear"! And "bites" with "anally violate"!

    Grin and bear it! Barry, an 850 lb. black bear, got a little frisky with zookeeper Ron Gilks. The anal rape is believed to be the first inter-special coupling in Metro Zoo history.
    Yes, last Saturday a zookeeper at the Metropolitan Zoo had "claws" for alarm when he was attacked and raped by the same black bear he had raised from a cub! Geez, talk about gratitude!

    "It was horrible, just horrible," sobbed an eyewitness. Guess she sure got an eyeful!

    The bear, named "Barry," attacked zookeeper Ron Gilks as Gilks entered the cage to give him dinner. Barry lunged at his throat, goring him with his huge claws and razor-sharp teeth. Some of the claw marks were three-quarters of an inch deep. Ouch!

    Then, astonished onlookers could "bearly" believe what happened next--Barry began to brutally rape zookeeper Gilks!

    Frantic zookeepers rushed for rifles as others tried to divert the bear. But there was no stopping Barry! This bear kept "bearing down," and Gilks just had to grin and "bear" it! Maybe Barry was mistaking him for his "honey"!

    Gilks was pronounced dead upon arrival at the hospital. A full quart of bear semen was extracted from his ruptured chest cavity. And that's no small Boo-Boo!
    Barry's 27-inch phallus, armed with guard hairs as sharp as red-hot needles, shot through Gilks' rectum, shattered his lower spine and skewered his colon, causing his entire lower torso to "cave" in! Yikes! Bet that wasn't the type of "cave" you had in mind when you took up zookeeping, Mr. Gilks!

    And can you imagine Gilks' surprise when Barry's putrid ursine semen flooded his ruptured chest cavity? (By the way, Mr. Gilks, whatever cologne you've been wearing, where can the public get some?)

    Finally, zookeeper Eric Pulliam shot Barry with a tranquilizer gun and pulled Gilks from the cage. The unconscious bear was later destroyed. Hey, this "Yogi" made a major "Boo-Boo"!

    "I have worked with dangerous animals before," zoo director Kate Donegal said. "But never have I seen any animal sexually assault a human being." "Barry"? Try "Scary"!

    Meanwhile, Gilks was pronounced dead at an area hospital--but at least he died grinning and bearing it! No doubt, this episode gives new meaning to the term, "Do not feed the bears!"

    --

    Goat: It's what's for dinner!

  29. Awesome. by Anonymous Coward · · Score: 2, Funny

    Now can we have an article on how to make the BFG?

    C'mon, please? I wanna know the physics behind whatever the deal is with that "cone" thing.

  30. I sure would love to see this page... by TheMonkeyDepartment · · Score: 4, Funny

    THE RESPONSIBLE WAY TO SOLVE THIS PROBLEM:

    Dear Web Administrator:

    The editors at Slashdot.com are about to link to your site. With your permission, we will make a site mirror available at no charge to you. This mirror will be available for the next 5 days, and will be linked from our article, sparing you thousands of simultaneous connections which might bring your puny server to a halt. By the way, we can afford to do this, because we are now charging for ad-free page views, didn't you hear?

    Please contact us by [date] and let us know if we may mirror your site. If not, the story will be published on [date] and your site may experience the "Slashdot Effect."

    1. Re:I sure would love to see this page... by ewieling · · Score: 1

      Dear Slashdot Editors,

      Do not set up a mirror site. It will deprive us of ad revenue and we will sue you for every penny you have.

      Regards,

      Web Administrator

      --
      I really shouldn't have used someone else's email address for this account.
    2. Re:I sure would love to see this page... by bartenderpho · · Score: 1
      Personally I think they should send something like this (totally tongue in cheek of course):

      Dear Web Administrator:

      The editors at Slashdot.com are about to link to your site. With your mandatory donation of $XXXXX we will make a mirror site available to you. This mirror will be made avialable for the next few days and will be linked from our article. This small donation will spare you and your ISP the severe agony and humilitaion of failing a slashdotting. If a donation is not made we may consider running the offending story every 2 to 3 weeks.

      Maybe if Slashdot used a more extortion oriented buisnees model they wouldn't have to charge for advertising free page views >:).

      Maybe Slashdot could also charge to not run stories. I would love to see Microsoft pay up.

      Happy Slashdotting!

    3. Re:I sure would love to see this page... by geekoid · · Score: 2

      the liabilty issue would be tremendous if they did this. every site ever /.ed would be calling lawyer.
      Plus, when was the last time any reported asked permission to film.report on any thing that can be remotly considered public?
      you basically saying, hey we know your bandwidth costs will go through the roof, and your site may go down and were not taking responsibility.
      What happens when people starting saying "no I don't want you to mirror the site, and since you know you will bring my site down, I will consider it an "attack" and have my lawyers contact you.

      --
      The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
  31. Well... by Bugmaster · · Score: 4, Informative

    Strictly speaking, this is not a gauss gun. A real gauss gun would use the Lentz (sp?) effect or something similar to accelerate the ball down the rails; this weapon, however, is built entirely out of plain old permanent magnets and kinetic energy. Actually, I suppose that maglev trains could be considered as gigantic gauss guns also, though they do not use the Lentz effect.

    --
    >|<*:=
    1. Re:Well... by Phanatic1a · · Score: 5, Informative

      Well, it's a "gauss gun." Gauss = magnetic flux density. It's true that this isn't a railgun, which accelerates a projectile by means of the Lorentz force on the projectile which arises from the interaction of the current through the projectile and the magnetic field created by the passage of that current. But "gauss gun" is something of a catch-all phrase which comprises railguns, coilguns, and so forth. I guess if you wanted to you could even refer to linear induction motors as gauss guns.

    2. Re:Well... by Anonymous Coward · · Score: 0

      Gauss = dead scientist

      So a gauss gun shoots dead scientists at people...? Ew!

  32. Full-size gun by Reality+Master+101 · · Score: 2, Interesting

    Wow, this is exceptionally clever. The only other gauss rifles I've seen talked about used electromagnets and big-ass power.

    It makes me wonder... could this scale? What if you built a big version with, say, 50 pound explosive charges (delayed fuse, of course) and big magnets? It seems like with enough phases, you could make a pretty devastating launcher. And I bet it would be pretty damn accurate, too.

    --
    Sometimes it's best to just let stupid people be stupid.
    1. Re:Full-size gun by maxume · · Score: 2

      My intuition says that such a thing would rip itself to pieces. Somebody tell us the answer.

      --
      Nerd rage is the funniest rage.
    2. Re:Full-size gun by Anonymous Coward · · Score: 0

      Don't know; does this scale if the magnets are doughnuts? and the little steel ball flies through them?

      Why does the steel ball have to hit the magnet?

    3. Re:Full-size gun by Phanatic1a · · Score: 2

      It makes me wonder... could this scale?

      No, not that much. Even the very strongest permanent magnets are too weak to do much with a massive projectile. A really strong permanent magnet clocks in at around 2 T, but ~12 T is considered pretty routine with superconducting magnets.

      The advantage in a railgun is that you don't need magnets at all. The magnetic field arises purely from the passage of current. More current, a stronger magnetic field.

      Now, the very strongest magnetic fields that we can create at all are created by explosive collapse, and this achieves (brief!) field strengths of 40 T or greater. If you could time everything right, you could probably launch a helluva projectile at helluva velocities. It would be a bit of a one-shot weapon, though.

    4. Re:Full-size gun by Repton · · Score: 3, Insightful

      It's basically slight-of-hand with kinetic energy.

      If you just had one ball and a lot of doughnut magnets that the ball rolls through, you wouldn't get anywhere: The energy the ball gained as it rolled towards a magnet would be lost at it rolled through and away from that magnet.

      By having the ball hit the magnet, and having two balls on the other side, energy is transferred (like in a Newton's Cradle) from one ball, which is touching the magnet (and, thus, difficult to shift) to another ball, which is further away from the magnet, and hence requiring less energy to get "free".

      It's quite clever :-)

      --
      Repton.
      They say that only an experienced wizard can do the tengu shuffle.
    5. Re:Full-size gun by Chagrin · · Score: 3, Insightful

      At low speeds, the elasticity of the magnets or balls isn't much of an issue as the ball clicks up against the next magnet. However, towards the end of your gun, with the balls striking the magnets at ever-increasing speeds, I think you'd start shattering everything.

      --

      I/O Error G-17: Aborting Installation

    6. Re:Full-size gun by gabba_gabba_hey · · Score: 1

      You're absolutely right, but I'm tempted to find out just what the critical point is ;) I bet you might just get some decent velocity before you reached that point. Although in the article they mention that these magnets are fragile, so their 4 pack might just be around that limit.

    7. Re:Full-size gun by einhverfr · · Score: 2, Informative

      At some point the collisions destroy the magnets (as per the article). This can be extended by using better materials, etc.

      However there is one more limiting factor-- reloading the darned thing. So you have BIG magnets-- how do you reseat the balls between the magnets which transfer the energy. If you don't do this, you don't get the energy changes necessary to project the projectile anywhere (and you have the explosive charge....)

      This rail gun is human muscle powered and the magnets simply create a storage vessel for the energy.

      --

      LedgerSMB: Open source Accounting/ERP
    8. Re:Full-size gun by Reality+Master+101 · · Score: 2

      This rail gun is human muscle powered and the magnets simply create a storage vessel for the energy.

      That's what I find interesting about this: Could it be a poor-man's (or poor country's) railgun? So what if you had to have a couple hundred slaves\\\\\\ soldiers reset the balls before firing? If you could accelerate a payload and fire a few hundred miles, it could be pretty devastating. I know that the US has some big-ass cannons that can do that, but I'm sure it's pretty tricky technology.

      Anyway, it's probably not practical given the limits of permanent magnets and the inherent wear-and-tear on every firing.

      --
      Sometimes it's best to just let stupid people be stupid.
    9. Re:Full-size gun by kojikun · · Score: 1

      Youre wrong you know.. A rail gun DOES need magnets otherwise the lorentz force will not exist. It needs the magetcs to surround the rails perpendicular to them but along the same axis. The magnetic field in the projectile pushes against the magnetic field of the magnet.

      A good question, tho, is could you build a magnetic gun using a magnetic projectile and a massively powerful electromagnet at the end. Then use a burst of magnetism to send the smaller magnet flying. Just a thought. ^^

  33. A gauss gun? by Anonymous Coward · · Score: 0

    After you use this gauss gun, you better have a gauze gun handy...

  34. No future for @home. by Anonymous Coward · · Score: -1, Offtopic

    It's a well known fact that DSL is just second rate to cable. The ill-informed DSL guys will tell you how great it is and all, a nice dedicated connection - but they won't tell you it's dedicated to the switch. The point being, you've got all these people pirating mp3s, porn, and software and you still are gonna get shitty service. Let's just hope you live across the street from the telco's switching equipment. The telco's have no reason to maintain their lines either, they have to open it up to other companies which look bad when bell decides to get around to fixing a problem on the lines - they make money by neglecting their equipment.

    @home shot itself in the foot by offering crappy DSL service.

    Cable on the other hand is not regulated meaning they have don't have to open their systems for shit. They generally provide better service anyway. In a 2001 Newsweek report it stated that the DSL market has shruken nearly a staggering 14% in one year, 9% of that in the last quarter alone. If you own stock in any of the other big DSL companies such as Verizon, Swbell, or @home then you are in for a big surprise. Lets just hope you enough bandwidth to come crying on slashdot when your company leaves your ass hanging in the breeze.

    Fact: @home is DEAD.

  35. Lest us not forget Battletech by Magus311X · · Score: 1

    Don't forget the wonderful arm-mountable gauss rifles in FASA's Battletech.

    Mechs were fusion powered if I can recall correctly, so they could actually generate the massive amounts of power possible to make them somewhat feasible as a weapon.
    -----

  36. I can just see this happening ... by tempestdata · · Score: 3, Interesting

    Some kid will make the gauss gun,...authorities will find out about it, and claim that he was going to use it to shoot up some kids at school.. it will be taken as further evidence that Computer games (Quake) cause violence in children... yadda yadda yadda...

    --
    - Tempestdata
    1. Re:I can just see this happening ... by km00re · · Score: 1

      I can imagine the airports installing Hall Effect detectors to scan passengers for magnetic devices...

      --


      KM
  37. Dangerous by Anonymous Coward · · Score: 0

    I don't see the rule as being a dangerous weapon. I doubt the thing would be able to put a hole threw wet papper.

  38. Violence in Video Games? by Anonymous Coward · · Score: 0

    I thought you guys said violence in video games didn't cause violence in real life :-)

  39. Something similar by seanadams.com · · Score: 4, Informative

    Here's a coil gun I found on google.

    Instead of using fixed magnets to release the energy of the balls hitting each magnet in sccuession, this coil gun uses a series of timed pulses to accellerate the projectile down the length of a tube. That's a block of concrete in the photo, and I think the black spike in the top left corner is the projectile.

    http://www.resonanceresearch.com/prod06.htm

    1. Re:Something similar by crystalplague · · Score: 1

      *lights dim*

      "whats that?"

      "timmy's just playing with his railgun again"

  40. Ok... by cr0sh · · Score: 3, Interesting

    From what I understand, this gun is basically the same thing as the "Newton's Pendulum" toy that clacks back and forth, but with the addition of magnets between the balls, and some distance, to cause the balls to all pick up speed so that the last one gets a lot of kinetic energy transferred to it.

    Scaling it up would seem feasible, but the problem would be the shattering magnets, as well as to "reload" you would have to physically move each ball back to the starting point.

    Here is where I wonder if this thing could be made "better". The problem is getting a magnet as strong as the ones used, but doesn't shatter - but I think it can be done...

    Get a non-ferrous tube - an alluminium or piece of PVC pipe would do fine. Get it with an inside diameter just smaller than the ball you want to fire.

    Now, wind up some "double ended" electromagnets - use very fine magnet wire, and do an excelllent job winding the magnets. Use a steel core, and wind them to the thickness of the inside diameter of the tubing. You need these electromagnets to be really strong.

    Now, cut 1.5 or 2 inch lengths of the tube - put the magnet on one end, and a ball - secure the magnets extremely well. Then, "stack" the tubes together to make a long tube, so that there is a magnet and a ball between the two magnets.

    One end (the "breech") leave a 3 inch piece of tube, and build some kind of "firing mechanism" (spring loaded or something to propel the ball against the first electromagnet). Do the same on the other end, but just the tube - no firing mechanism - you may want this end to be a little longer.

    To load and fire:

    Get a real big-ass current capacity power supply, and hook the magnets up to turn them on. Don't turn them on yet - tilt the tube up to cause all the other balls to fall to the magnets, then turn on the magnets. Load the ball on the front end (the firing chamber end), and a ball into the firing mechanism. Fire the ball - and, if everything goes right (and my back of the napkin calcs are correct - yeah right), it should do the same thing as the small version, only more powerful (maybe), and reloadable!

    --
    Reason is the Path to God - Anon
    1. Re:Ok... by Yarn · · Score: 1

      Hmm, I think this might even work... Wonder if I can scrounge some ceramic superconductor + liquid nitrogen to take this to the next level :)

      --
      -Yarn - Rio Karma: Excellent
    2. Re:Ok... by Anonymous Coward · · Score: 0

      got a better way, easier too. Just get some solid threaded(threadings not important but its the only kind they sell) steel rods like you find at home depot. Then get a aluminum pipe that somewhat matches the diameter. Drill a couple holes at where the steel rods should be, cut a hole in the rod to match the hole in the tube. The idea is that if you got say a 5 foot tube and a bunch of little rods in there secured by a bolt through the rod and pipe with ball bearings in between them, then you could wrap the coil on the outside of the pipe and simplify the contruction process.
      then the same thing you said, shut off the current, tilt the pipe back, turn the current on, and let the ball at the bottom go.

  41. Mirror Here by Inthewire · · Score: 1
    --


    Writers imply. Readers infer.
    1. Re:Mirror Here by Inthewire · · Score: 1

      Now that the slashdotting has passed, the mirror has been taken down.

      --


      Writers imply. Readers infer.
  42. I'd like to stick my guass gun in her! by senior_troll · · Score: -1

    Today's Cock Lengthening Troll brought to you by Senior Troll and the letter G (it's a G thang)Genghis Troll real_b0fh CmderTaco The BOFH Troll RoboTroll Mayor McPenisman The_Fire_Horse Carp Flounderson aria-giovanni.tv_0001.jpg aria-giovanni.tv_0002.jpg aria-giovanni.tv_0003.jpg aria-giovanni.tv_0004.jpg aria-giovanni.tv_0005.jpg aria-giovanni.tv_0006.jpg aria-giovanni.tv_0007.jpg aria-giovanni.tv_0008.jpg aria-giovanni.tv_0009.jpg aria-giovanni.tv_0010.jpg aria-giovanni.tv_0011.jpg aria-giovanni.tv_0012.jpg aria-giovanni.tv_0013.jpg aria-giovanni.tv_0014.jpg aria-giovanni.tv_0015.jpg aria-giovanni.tv_0016.jpg aria-giovanni.tv_0017.jpg aria-giovanni.tv_0018.jpg aria-giovanni.tv_0019.jpg aria-giovanni.tv_0020.jpg aria-giovanni.tv_0021.jpg aria-giovanni.tv_0022.jpg aria-giovanni.tv_0023.jpg aria-giovanni.tv_0024.jpg aria-giovanni.tv_0025.jpg aria-giovanni.tv_0026.jpg aria-giovanni.tv_0027.jpg aria-giovanni.tv_0028.jpg aria-giovanni.tv_0029.jpg aria-giovanni.tv_0030.jpg aria-giovanni.tv_0031.jpg aria-giovanni.tv_0032.jpg aria-giovanni.tv_0033.jpg aria-giovanni.tv_0034.jpg aria-giovanni.tv_0035.jpg aria-giovanni.tv_0036.jpg aria-giovanni.tv_0037.jpg aria-giovanni.tv_0038.jpg aria-giovanni.tv_0039.jpg aria-giovanni.tv_0040.jpg aria-giovanni.tv_0041.jpg aria-giovanni.tv_0042.jpg aria-giovanni.tv_0043.jpg aria-giovanni.tv_0044.jpg aria-giovanni.tv_0045.jpg aria-giovanni.tv_0046.jpg aria-giovanni.tv_0047.jpg aria-giovanni.tv_0048.jpg aria-giovanni.tv_0049.jpg aria-giovanni.tv_0050.jpg aria-giovanni.tv_0051.jpg aria-giovanni.tv_0052.jpg aria-giovanni.tv_0053.jpg aria-giovanni.tv_0054.jpg aria-giovanni.tv_0055.jpg aria-giovanni.tv_0056.jpg aria-giovanni.tv_0057.jpg aria-giovanni.tv_0058.jpg aria-giovanni.tv_0059.jpg aria-giovanni.tv_0060.jpg aria-giovanni.tv_0061.jpg aria-giovanni.tv_0062.jpg aria-giovanni.tv_0063.jpg aria-giovanni.tv_0064.jpg aria-giovanni.tv_0065.jpg aria-giovanni.tv_0066.jpg aria-giovanni.tv_0067.jpg aria-giovanni.tv_0068.jpg aria-giovanni.tv_0069.jpg aria-giovanni.tv_0070.jpg aria-giovanni.tv_0071.jpg aria-giovanni.tv_0072.jpg aria-giovanni.tv_0073.jpg aria-giovanni.tv_0074.jpg aria-giovanni.tv_0075.jpg aria-giovanni.tv_0076.jpg aria-giovanni.tv_0077.jpg aria-giovanni.tv_0078.jpg aria-giovanni.tv_0079.jpg aria-giovanni.tv_0080.jpg aria-giovanni.tv_0081.jpg aria-giovanni.tv_0082.jpg aria-giovanni.tv_0083.jpg aria-giovanni.tv_0084.jpg aria-giovanni.tv_0085.jpg aria-giovanni.tv_0086.jpg aria-giovanni.tv_0087.jpg aria-giovanni.tv_0088.jpg aria-giovanni.tv_0089.jpg aria-giovanni.tv_0090.jpg aria-giovanni.tv_0091.jpg aria-giovanni.tv_0092.jpg aria-giovanni.tv_0093.jpg aria-giovanni.tv_0094.jpg aria-giovanni.tv_0095.jpg aria-giovanni.tv_0096.jpg aria-giovanni.tv_0097.jpg aria-giovanni.tv_0098.jpg aria-giovanni.tv_0099.jpg aria-giovanni.tv_0100.jpg aria-giovanni.tv_0101.jpg aria-giovanni.tv_0102.jpg aria-giovanni.tv_0103.jpg aria-giovanni.tv_0104.jpg aria-giovanni.tv_0105.jpg aria-giovanni.tv_0106.jpg

    1. Re:I'd like to stick my guass gun in her! by Anonymous Coward · · Score: -1, Troll

      I propose that your penis size is inversly proportional to your postings length. Go finger-fuck yourself, ass-monkey cum-guzzling queeve-sniffer. Sucka ona 'dat!

  43. Circular track explanation is flawed.. by rufusdufus · · Score: 1, Redundant

    The explanation for why a circular track won't make a perpetual motion machine has some misleading statements in it. In several places he talks about "energy to be had from this magnet". However, none of the fixed magnets imparts energy to the ball.
    So where does the energy come from? Why, from your hand of course! The process of placing the balls into their starting position imparts the energy.

    1. Re:Circular track explanation is flawed.. by Jagasian · · Score: 1

      Well, the separation of the two magnets creates something similar to gravitational potential energy. The magnet that the ball is touching at rest acts as "glue" holding the ball above the magnet away from it (the anology to gravity makes this far away magnet the ground).

    2. Re:Circular track explanation is flawed.. by rufusdufus · · Score: 3, Interesting

      Not quite. The magnets create a magnetic "force field". As you recall from physics 101, energy is defined is force times the delta of distance, not force alone. The energy of separating the magnets is not 'released' during this experiement, as the magnets do not move. Thus, the energy comes from your hand placing the balls which move.
      Gravity also does not impart energy to falling objects; the objects already have energy relative to the earth, and actually lose energy to the earth on impact.

    3. Re:Circular track explanation is flawed.. by Joe+Decker · · Score: 1
      Not quite. The magnets create a magnetic "force field". As you recall from physics 101, energy is defined is force times the delta of distance, not force alone. The energy of separating the magnets is not 'released' during this experiement, as the magnets do not move.

      It's true that the magnets don't move--what's released is the potential energy of the magnet in its set state (a whole ball away from the left magnet) minus its potential energy in its fired state (in contact with the right magnet).

    4. Re:Circular track explanation is flawed.. by Anonymous Coward · · Score: 0

      It's not flawed: the magnet exerts an (electromagnetic) force on the ballbearing, accelerating it. That's energy.

  44. Re:In case of /. effect-Bouncy,bouncy. by Anonymous Coward · · Score: 0

    [Posted & E-mailed]

    "How high does your ball bounce? Send me mail with your results."

    Depends on who's on top.

  45. so, you people want to build a gun eh? by SevenTowers · · Score: 4, Interesting

    Instructions to build a gun that shoots a magnet at 2KM/second. Yes you read correctly. Get a 3 meter long pipe made of pure iron. Coil 400km of thin copper wire around it. Buy a cylindrical magnet, the strongest you can get, that fits inside the pipe. Buy the fattest AC/DC converter around (or build it yourself...) and plug it in a 5000 Volt power supply (think neighbourhood electrical supply). Connect this to the 2 ends of the wires around the pipe.

    Oh ya, make sure it's pointing the right way around.

    My physics teacher did this while he was in university. They shot a concrete wall 2 feet thick and the magnet went through. The velocity was 2KM/s.

    --
    Imperium et libertas
    Autocracy and freedom
    1. Re:so, you people want to build a gun eh? by jsarek · · Score: 1

      Wow, only FOUR HUNDRED KILOMETERS OF WIRE... and a 5000volt power supply... hold on while I start mass producing these.

    2. Re:so, you people want to build a gun eh? by jsarek · · Score: 1

      Oh and by the way, did your physics teacher's gun explode into flames and reduce the whole thing to slag when he connected the wires to the power source?

      That wouldn't necessarily be bad, I was just wondering. :D

    3. Re:so, you people want to build a gun eh? by rjh · · Score: 1, Flamebait

      400km of thin copper wire is an awful lot. Try, "the width of northern Missouri".

      Wall sockets are either 110V or 220V (sometimes listed as 120V/240V). Nowhere near five thousand. Not even in Europe, where they use much higher voltages, is a wall socket five thousand volts.

      With a muzzle velocity of 2000m/s and a muzzle of only 3m, you can be damn sure that the payload would shatter and deform under the hundreds of thousands of G-forces.

      You're also neglecting the fact that at 2000m/s, air has the consistency of concrete. The payload wouldn't even get out of the muzzle. It would explode in the muzzle, you'd get a burst barrel, and you'd have 400km of fragmented copper wire bouncing around and killing anyone who was standing too close.

      At 2km/s, the concrete wall wouldn't just be breached. It would explode. Everyone around would be dead. There would also be liquified metal (from the payload) spraying everywhere, setting fires.

      The sheer amount of energy required to launch a payload at 2km/s from such a short barrel would require a current far in excess of anything THIN copper wire could bear. Not only would the barrel burst and copper go flying everywhere, the copper would be molten.

      The next time you decide to spin a totally BS yarn, please at least check to make sure the physics works.

    4. Re:so, you people want to build a gun eh? by SevenTowers · · Score: 4, Insightful

      So fuckin what if it's the width of northern missouri?

      Take a look at this page before talking about something you don't know about. Do you know how much energy you can get out of an electromagnetic field generated by a solenoid that's got 400km of wire? A hell of a lot. Oh, yah, do planes that fly at mach 7 burst into flames? It's gonna heat up like hell that's for sure. And by the way, the payload they accelerated was of the order of a few grams.

      Have you ever heard of people being in a separate room? And the concrete wall being in the middle of a room with about 10 meters of water barrels behind it.

      Don't think people are stupid before knowing the whole story. Every one aound would be dead, that has to be the stupidest I have ever heard. You check your physics dude, because expirements with explosives and high velocity projectiles happen everyday and people don't die.

      --
      Imperium et libertas
      Autocracy and freedom
    5. Re:so, you people want to build a gun eh? by SevenTowers · · Score: 2

      And who's talking about wall sockets? The voltage coming in over wires in neighbourhoods is usually 5000 volts. It gets converted down to 220 or 110 for home usage in big downconverters that are either up in the poles (big gery cylinders) or buried. The reason the voltage is so high is to reduce energy loss over long distances.

      --
      Imperium et libertas
      Autocracy and freedom
    6. Re:so, you people want to build a gun eh? by coding_ape · · Score: 3, Insightful
      The armor piercing rounds of a standard American tank cannon (120mm Rheinmetall) have a muzzle velocity of around 1800m/s. The length of the barrel is around 3-4 m. So no, the payload would not shatter under the strain. And that's total bull about the air having the consistency of concrete. Like the previous poster said, we couldn't exactly expect missiles and rockets to fly at mach 4+ if they were slogging through concrete.

      Oh yes and though the voltage inside your house may be 120v, the voltage in the lines outside is much, much higher. That's why they use AC, so they can transform it.

    7. Re:so, you people want to build a gun eh? by trip11 · · Score: 1

      Assuming that he just 'tapped' the wires together long enough to create a flux, there will be a HUGE resistance in the wire from the fact it is wound and there is inductive resistance. Also resistance in a wire goes up for longer wires, and thinner wires. 5000 volts isn't unresonable. But I"d work with a very small current in that case.

    8. Re:so, you people want to build a gun eh? by KFKsingultus · · Score: 2, Insightful

      The sheer amount of energy required to launch a payload at 2km/s from such a short barrel would require a current far in excess of anything THIN copper wire could bear. Not only would the barrel burst and copper go flying everywhere, the copper would be molten.

      You don't know much about physics do you?

      All the wire has to do is carry the amperage it's being fed. The energy is generated by a variation in magnetic flux. This has absolutly nothing to do with melting the wire. If the amperage is high enough, yes the wire could overheat, but since it's so long, I don't think you need that much current.

      --
      I follow the 2 major laws of thermodynamics : maximum entropy, minimum enthalpy.
    9. Re:so, you people want to build a gun eh? by Dyolf+Knip · · Score: 2, Interesting
      s = s0 + v0*t + 1/2*a*t^2 and
      v= v0 + a*t
      right?

      The final velocity, v, is 2000 m/s, so t=2000/a.

      The final distance is 3m, initial velocity and distance 0, so 3 = 1/2*a*t^2, substituting in what we know for t...

      The acceleration is six hundred and sixty-six thousand gees. From this I concur with your estimate that the 2kps story is in part a load of bullshit.

      --
      Dyolf Knip
    10. Re:so, you people want to build a gun eh? by canadian_right · · Score: 4, Informative
      You are just silly as the person you are insulting.

      2000ms over a 3m barrel is not "hundreds of thousands of G's" its about 66G. Your average 24" (less than a .5m) rifle barrel acclerates a lead slug to about 1100m/s. This is about 220g. Air does not become concrete, the rifle does not explode. BTY 1G is 9.98m/s per sec.

      As for 5000v, I thought you wanted lots of amps for a solenoid, but it is a small matter to ramp up/down a voltage using a transformer (which is just two coils, one inside the other).

      So while I'm sure making a rail gun isn't that simple your "science" is just as bad. Might want to read a 1st year phyics book.

      --
      Anarchists never rule
    11. Re:so, you people want to build a gun eh? by Anonymous Coward · · Score: 0

      Did something similiar when I was younger. Won the 6th grade science fair for it. Problem was, my partner reversed a wire (and left it exposed)and I got the "slightly-sizzled-standing-on-end" hair as all the breakers popped.

    12. Re:so, you people want to build a gun eh? by Latent+IT · · Score: 1

      Yeah, I hope for your sake, you're a troll. Otherwise, you're just a big, smug, total moron. ;p

      A ball being pulled towards or being pushed by a magnet will never deform, because the magnet is pulling on each bit of the ball, rather than being pushed from behind like a bullet.

      And several people above have addressed your problems with high speed air resistance, and I'd I'm sure a trained chimp will happen by and mock you without mercy for trying to tell this guy the voltage of a wall socket. ;)

    13. Re:so, you people want to build a gun eh? by Latent+IT · · Score: 1

      You're off by uh... 10^4? Or so. 2000m/s isn't much faster than a high powered rifle bullet (way less than 10x faster, at least) and well, I've never seen a molten bullet. Did you do 2,000 km/sec?

    14. Re:so, you people want to build a gun eh? by Dyolf+Knip · · Score: 2
      Err, don't think so. I used 2000 meters per second velocity, 3 meters distance, and gees are in meters/second^2, so the units are all consistent. Plugging t=2000/a into the t^2 yields 3=1/2*a*4,000,000/(a^2) -> a=2,000,000/3. Did I mess this up somewhere?

      But you may be right about the rest. It's a ridiculous acceleration but it doesn't last very long. I would like some kind of documentation on the thing, though. A mach 6 railgun doesn't seem to be the type of project someone does in his spare time.

      --
      Dyolf Knip
    15. Re:so, you people want to build a gun eh? by gnovos · · Score: 2

      Take a look at this page [google.com] before talking about something you don't know about. Do you know how much energy you can get out of an electromagnetic field generated by a solenoid that's got 400km of wire?

      Rail guns and coil guns are different, they work on completely different properties of magnetics. For a rail gun you need exactly ZERO coils of copper wire. All you need are two very expensive rails, a few rare earth magnets and a huge bank of incredibly dangerous capacitors. And just a little prayer that you don't fuse your slug to your rails and waste a good $400.

      How do I know this? I actually build rail guns.

      --
      "Your superior intellect is no match for our puny weapons!"
    16. Re:so, you people want to build a gun eh? by Restil · · Score: 2

      You have about 50,000 miles of blood vessels in your body. 400km doesn't seem like a whole lot in the grande scheme of things.

      5000 volts isn't hard to come by either. Ever hear of capacitors? You charge up the caps, then use them to release the power needed. Then
      charge them up again for the next shot. They could run off of wall current or any battery, it all depends on how much power it needs for the discharge that matters how often you could shoot.

      -Restil

      --
      Play with my webcams and lights here
    17. Re:so, you people want to build a gun eh? by SevenTowers · · Score: 2

      I totally agree with you :) Never said the contrary, I was just exposing the makings of another type of gun. Some people just didn't seem to believe me.

      --
      Imperium et libertas
      Autocracy and freedom
    18. Re:so, you people want to build a gun eh? by Sycraft-fu · · Score: 3, Informative

      Dude, you might want to check you facts before insulting someone. You are wrong on so many counts. First, 2000m/s over 3m is NOT hundreds of thousands of Gs, it's roughly 65G. Second, this velocity is not out of the area of regular conventional weapons. For example the standard military M16 which shoots 5.56mm ammo has an exit velocity of around 1000m/s with powerful steel core ammo. With a gun designed for higher velocities, like a high accuracy varmit rifle, 2000m/s is not beyond reach. Air does not become concrete, and yes, 5.56 ammo from an M16 WILL punch through concrete block but no, it doesn't explode.

      What you are forgetting is that modern projectile weapons trade mass for velocity. A standard 9mm pistol fires a bullet that has a mass of only 8 grams. By rifle standards, that is huge. Your standard 5.56mm round is only about 3.5-4 grams. It sounds as if this rail gun was much the same. I don't imagine that the magnet used weighed very much.

    19. Re:so, you people want to build a gun eh? by Dahan · · Score: 1

      g isn't 1 m/s^2, it's around 9.81 m/s^2. So 666667 m/s^2 is around 68000 gees.

    20. Re:so, you people want to build a gun eh? by Hank+the+Lion · · Score: 1

      You are just silly as the person you are insulting.

      > 2000ms over a 3m barrel is not "hundreds of thousands of G's" its about 66G. Might want to read a 1st year phyics book.


      Please, show me your calculation (from that 1st year physics book)
      When I do the calculation, it goes:

      a*t = 2000 m/s
      1/2*a*t2 = 3m = 1/2 * (a*t) * t = 1/2 * 2000m/s * t
      ==> t=3 ms.
      a=2000 m/s / t ==> a=666666 m/s2 = 67957 g.

      OK, this is a factor 9.81 lower than Dyolf Knip found, because he omitted that 1g = 9.81 m/s2, but still a factor 1000 greater than you stated.

      Please don't call people silly when your own math is not perfect, and, moderators, please do not mod posts up as informative when a little checking proves them more wrong than the post they are criticizing!

    21. Re:so, you people want to build a gun eh? by psych031337 · · Score: 2
      400km of thin copper wire is an awful lot. Try, "the width of northern Missouri".

      The human lung consists of bubbles that will easily cover a soccer field when (theoretically) removed and expanded. Is your chest the size of a soccer field? No? You still have that awful lot of lung bubbles with you, pal.

      Wall sockets are either 110V or 220V (sometimes listed as 120V/240V). Nowhere near five thousand. Not even in Europe, where they use much higher voltages, is a wall socket five thousand volts.
      Again, so what? These voltages can be created from the proper current. Ever heard of that nifty peronsl protection devices that send a electrical shock into the person assaulted? They're in the range of 10s of thousands volts. Yet they work in the US where there are no power outlets with these properties. There's even more surprise to it - they can operate off a 9V block battery. Generating a voltage of a few thousand is probably an easy project for someone in the physics field (which I am not, I just aenjoy a broad general knowledge).

      With a muzzle velocity of 2000m/s and a muzzle of only 3m, you can be damn sure that the payload would shatter and deform under the hundreds of thousands of G-forces.
      Weird. I remember sending a few grams of lead through a much shorter barrel (like 1 m) at speeds around 750 to 900 meters/s without shattering either the muzzle/barrel or the projectile (the projectile usually got shattered after hitting the targets). This technique is one known to man for decades and has been steadily refined to what it today. You may have guessed it, i Am talking abour assault rifles (figures are for the german G3 rifle, while other rifle, esp sniper rifles can reach higher muzzle velocitys...)

      There would also be liquified metal (from the payload) spraying everywhere, setting fires.
      Well, if this was ture, we certainly would have a military version of this thing. Liquid metal spraying everywhere and setting fires is a militarists wet dream. I am sure the payload would get quite hot and uncomfy to stop with your hand, but i think it would stay solid. The impact might lead to a rise in temperature throughout the projectile because molecular friction will jump to the max for a fraction of a second, but what the heck - even if it was cold it would be deformed by then.
      --
      +++ath0
    22. Re:so, you people want to build a gun eh? by Anonymous Coward · · Score: 0

      ignoring most of your misinformed comments, heres the one i find most annoying... why would the projectile shatter under any amount of acceleration? if the gun is well made and the payload is more or less homogeneous and has appropriate symmetry, the force is applied uniformly to every particle within the payload. no tidal forces == no stress.

    23. Re:so, you people want to build a gun eh? by jsarek · · Score: 1

      Look, if you can find 400km of thin wire that won't explode into flames/slag the instant you connect it to a 5000volt power supply, what are you doing posting to slashdot... get out there and create something useful.

    24. Re:so, you people want to build a gun eh? by pfdietz · · Score: 1
      Dude, you might want to check you facts before insulting someone. You are wrong on so many counts. First, 2000m/s over 3m is NOT hundreds of thousands of Gs, it's roughly 65G.

      You're off by a factor of 1000.

    25. Re:so, you people want to build a gun eh? by Dyolf+Knip · · Score: 2

      And so it is, my bad.

      --
      Dyolf Knip
    26. Re:so, you people want to build a gun eh? by ckedge · · Score: 1

      No, I've just done the math, and it is 66 thousand G.

      But you *are* correct that despite this great acceleration, it's not out-of-line with standard projectile weapons.

    27. Re: so, you people want to build a gun eh? by thebabelfish · · Score: 1
      That's awesome! Do you have any more info (specs, etc)? Oh, and is that a typo, or do you really need 400 kilometres of copper wire?

      ~ thebabelfish

      --
      "I don't trust goats," --To Catch a Spy
    28. Re:so, you people want to build a gun eh? by Yarn · · Score: 1

      I built a 5kV power supply that ran off a 9V battery.

      Not a great achievement, first make AC with a couple of medium power transistors, put that into a ferrite cored transformer, then put the 100 or so volts that come out up a diode/capacitor ladder

      --
      -Yarn - Rio Karma: Excellent
  46. OT: English by Anonymous Coward · · Score: -1, Offtopic

    I don't get this kind of concordance in English. Shouldn't it be "physics ARE fun"? I mean, "physics" is plural, isn't it? Or is it? Or was it the guy's mistake in writing "is" (which I don't think it was)?

    I also don't agree with other concordance rules like "The Police say he is guilty" (instead of "The Police says he is guilty"), although I see how it works. I am not saying it is wrong, I just don't agree. To me, the Police, as an organization, "says" that.

    And, if you have not gotten it so far, English is not my native language.

    1. Re:OT: English by DaCool42 · · Score: 1

      No, it's physics is fun. Refering to physics as a whole singular entity. Like the human race is... etc.

      --

      ----
      All of whose base are belong to the what-now?
    2. Re:OT: English by Anonymous Coward · · Score: 0

      Yeah, I get. Maybe this wasn't the best example, or I just didn't word it appropriately.

      Anyway, I still don't agree with "The Police..." :)

    3. Re:OT: English by dragons_flight · · Score: 1

      No, no.

      It's Physics is Phun!

  47. Re:Something similar-military. by Anonymous Coward · · Score: 1, Informative

    The military has been experimenting with coil & rail guns. Power issues keep this in the lab though.

  48. A few of the best pics.. by Matrim9 · · Score: 3, Informative

    mirrored, to avoid the Slashdot effect... http://spiff.homelinux.net/gaussgun/

  49. In case /. gets slashdotted by RMSIsAnIdiot · · Score: -1, Troll

    Homemade Gauss Gun

    Posted by michael on Friday March 01, @10:29PM

    from the physics-is-phun dept.

    bonzoesc writes: "I'm sure we all remember getting owned by some railgun-wielding kid in Quake2. Ever wanted a way to get back? Enter the Homemade Gauss Rifle. Requires wooden ruler with groove down the middle to serve as the rail, steel balls that can roll down the groove to use as projectiles, and magnets to store and redirect energy. Physics is fun!"

    --

  50. At least it doesn't melt. by dragons_flight · · Score: 4, Interesting

    When I read the title, I couldn't help thinking about burned spot in one of my old dorm's carpeting. A classmate of mine build a small rail gun using electromagnets, unfortunately during a test the coils melted, which left a very interesting splotch of solidified metal and burnt carpet.

  51. This is useless. by Wakko+Warner · · Score: 3, Funny

    It's nothing like the Quake rifle. I tried killing *THREE PEOPLE* with mine, and all it did was hit them in the head a little.

    What a waste of time!

    - A.P.

    --
    "Remember when the U.S. had a drug problem, and then we declared a War On Drugs, and now you can't buy drugs anymore?"
    1. Re:This is useless. by Mayor+McPenisman · · Score: -1

      I cannot stress this enough:
      You are a dummy dummy dumb dumb. Invest in cattle and noseclothes, they will improve relations with others as your pants melt off of your dumb body.

      Thanks.

      --
      [[Ay fukkand lyke ane furious Fornicatour]]
  52. Neat, but not really a gauss gun by DaCool42 · · Score: 2, Informative

    This is a neat little physics project, but it isn't a guass gun. A real gauss gun uses Lenz's law to propel the projectile. (It's can be a very powerful law, hehe...). The problem is that a real gauss gun of quake-like power would be much to large to carry. But they certainly are very cool.

    --

    ----
    All of whose base are belong to the what-now?
  53. They may seem fun . . . by OverlordQ · · Score: 3, Informative

    . . . although 'gauss'/'rail' guns may seem fun and interesting projects, unless your a really knowledgeable in the electical field, these are things you just shouldn't try on a large scale. You're dealing with large ammounts of heat and electricity which could explode, burn, shock and otherwise injure youself and others. Safety First!

    --
    Your hair look like poop, Bob! - Wanker.
    1. Re:They may seem fun . . . by nurightshu · · Score: 3, Funny

      Safety First!

      Actually, think for just a second: do you really want the sort of people who would half-ass the assembly of a railgun to breed? Personally, I'd rather that they eliminate themselves early in life.

      Besides, if everybody thought through every crazy stunt before they tried it, we'd put the Darwin Awards out of business.

      --
      They that would sacrifice their .sig space for that cliched Franklin quote deserve neither.
    2. Re:They may seem fun . . . by Ayatollah · · Score: 1

      "Cleaning the gene pool" jokes are hip these days, but come on. I'm so sick of hearing people want to leave everything up to the establishment.

      Where would we be without entrepreneurial spirit? Even bold and stupid moves inspire greatness. In others.

      Sometimes people fail dramatically, then succeed. Sometimes people fail dramatically, then die. But death breeds publicity, which can get the early adaptors to take notice.

      So give failure a break. It's more common than success, and just as necessary.

  54. w00 by Sk3lt · · Score: 1

    I'm going to lead my one man marble ball rail gun army now, terrorise everyone.. mwhahaha!

    Or not.. I don't have any magnets :(

  55. Spud Gun by fishlet · · Score: 1

    I like a spud gun much better. Just get some PVC pipe, some lighter fluid, A pipe end, a ignitor out of an old grill, and a Potato. Spray in the fluid, stuff in the potato, hit the button and boom. I must have shot a potato a good 250 feet once. Lotsa fun.

    1. Re:Spud Gun by kevinqtipreedy · · Score: 1

      ive gotten over 500ft. make one end out of 1" pvc, and have a converter to 3". put an end cap on the 3" section. put two screws on different sides, attatch to leads of spark ignitor and the arc will be inside. jam potato in 1" end. open end cap of 3 in side, spray in spray break cleaner, cap quickly. (1 short spray, dont flood it). press trigger.

    2. Re:Spud Gun by Anonymous Coward · · Score: 0

      Best propellent I can think of is starter fluid for your car, though I imagine those cans of pressurized butane are pretty good. Hmm. butane vs. ether.. I can't think off the top of my head which gives off more force

    3. Re:Spud Gun by Anonymous Coward · · Score: 0

      Bahh.. thats NUTIN'... I've prolly built about 10 or 15 spud guns (or cannons sometimes) and the best results i've had were with the larger "2-man" cannons... The barrel was standard PVC pipe that amazingly fit's both filled soda-cans AND tennis balls (check them, they're the same diameter!)
      Anyway, the barrel was roughly 8 feet long. The chamber was made of an 8" diameter insulated ABS pipe (don't want it to shatter!) and about 12" long. The end was a simple screw-on cap used to cover drain pipes... To ignite the fuel, you can take a kitchen stove lighter apart, and drill 2 small holes in the chamber to insert the wire leads... Then some duct-tape to keep the 'clicker' in place on the bottom of the chamber, plus to reinforce where you put two holes in a structural part of the cannon (trust me, it DOES break right there).

      For fuel, many reccomend using WD-40 or aresol hairspray... WHY?? Go to a auto-store or maybe a farm supply store and get something called "Engine Starter Fluid" which comes in a spray can like those dust-off air cans... This is the *BEST* substance we've used for this application. So, load a soda can, tennis ball, potato in the end of the barrel closest to the chamber, spray some starter fluid in the chamber and quickly screw the end-cap in place... Aim, and fire! (beware the unpredictable kick it can give)

      The results.. Although we never formally measured the distance we've fired a projectile, i know for a fact that we've reached distances around 250 meters. The most impressive results can be seen on firing at nearby objects.. We once "shattered" a full soda can firing against a wooden post. (by shattered, i mean it was in more than 20 pieces when we had to clean the debris up from the lawn...) Oh, and potatoes can be disposed of quite well with this device..

      BTW, one interesting caveat of this though.. I've heard a rumor that they (potato guns) are quite illegal, and are treated by law enforcement with the same severity as a sawwed-off shotgun.) I reccoment NOT shooting this in your backyard unless you live out in the middle of nowhere like i did.

      Have fun!
      ab2650-at-hotmail-dot-com

    4. Re:Spud Gun by Anonymous Coward · · Score: 0

      Bah! Spud guns are for the weak. A good match head cannon can shoot a 5lb chunk of metal over a thousand feet. You can take out a boat with one.

    5. Re:Spud Gun by Anonymous Coward · · Score: 0

      We did the same thing using a length of PVC, a potato, and an industrial fire extinguisher. A little over 400 feet. Booyah.

    6. Re:Spud Gun by Xawen · · Score: 1

      Combustion guns work well enough, but if you want REAL distance, try air pressure. My favorite gun that I've built so far works like this: One section of safety PVC (rated at 220 psi) capped at both ends acts as an air chamber. It has a tire valve on one end for pressurising with a tire compressor, and a valve on the other end that connects it to the barrel. The barrel is another piece of PVC, the same length as the air chamber. The two are connected with a solenoid sprinkler valve. You pressure the air chamber up to 100 psi, apply a little current to the valve, it snaps open and bang. I've gotten golf balls (special barrel attachment) almost 450 yards.

      See, a standard combustion gun gets about 15-25 psi in the chamber. Plus they make a mess. The air gun gets a solid, consistent high pressure blast every time. Notes of caution: use ONLY safety PVC rated at a MUCH higher psi than you will be using. Safety PVC has a seam that will burst if the pressure is too high rather than shattering. Also note that the sprinkler valve is only rated at 110 psi, so 100 should be the absolute maximum used. Remember, these ratings are liquid psi. Air has more force when compressed, so be careful. As dangerous as it can be, it's still a hell of a lot of fun...

  56. Not all of us by Wonko42 · · Score: 3, Funny
    I'm sure we all remember getting owned by some railgun-wielding kid in Quake2.

    Bah! I was that railgun-wielding kid in Quake 2!

  57. 2 birds with one stone by Aetrix · · Score: 3, Funny

    No, no no. We can get rid of the big ads and subscription service and simultaneously generate much more revenue for /. with this email:

    Dear Web Administrator

    The editors at Slashdot.org are about to link to your site in about 4 hours. You now have three options:
    1)You may see you bandwith destroyed as tens of thousands of /.ers destroy all that you have labored to create and may your servers cry. In addition, we will post links to your site several times over the next week.
    2)You may pay us a small fee to have us set up a mirror to your site, reducing the immediate hit but only prolonging your pain to the next 24 hours.
    3)You may pay us $2000 and not have this story posted. In addition, we will not link to your site for the next 30 days.

    --

    "One touch of Darwin makes the whole world kin." George Bernard Shaw
    1. Re:2 birds with one stone by Chris+Mattern · · Score: 5, Funny

      "Nice little website ya have here. Be a shame if it got slashdotted, ya know?"

      Chris Mattern

  58. How to build a: Degaussing gun by trip11 · · Score: 1

    If you take two strong magnents (I recomend ripping appart an old hard drive). Then pull out your electric drill (or better yet, dremel tool). Tape the two magnets to the end of a flat drill bit so that they attract to each other. What this makes is a large magnetic field at the end of your drill. Simply put your drill in front of the screen, turn it on high, and enjoy your screen tripping out :)

    1. Re:How to build a: Degaussing gun by Anonymous Coward · · Score: 0

      Use really good tape and don't hit the screen. You might end up with a faceful of shrapnel.

  59. Warning! Moderators on CRACK! by Anonymous Coward · · Score: 0

    RTFP!!!

    This rail gun involves physical magnets not electromagnets. You obviously didn't read the post and obviously the moderator that modded you up as informative didn't read the post.

  60. SLASHDOT IST TOT by Mr.+Piccolo · · Score: 0, Offtopic

    Slashdot is tot. Auf weidershen, mein Slashdot.

    --
    Glückwünsche, haben Sie Slashdot ermordet, indem Sie zum korporativen Druck beugten und Subskriptionen einlei
  61. My question by 1155 · · Score: 1

    My question is this...

    Will we see people in the automated taxi doing a drive-by with these?

  62. Re:Warning! Moderators on CRACK! by Anonymous Coward · · Score: 0

    yes, RTFP, he said rail/gauss guns in general, not this specific post as many people were alluding to making large scale guns.

  63. Several points look suspicious. by Christopher+Thomas · · Score: 5, Informative
    Background information about 'Gauss Guns' can be found here [http://www.powerlabs.org/coilguns.htm]

    I've spotted multiple errors in this person's page. It looks like he was cribbing notes from a more informed paper.

    Problems I've found:

    • A DC solenoid attracts only ferromagnetic materials. An AC solenoid repels any conductor.

      The authour claims that coilgun coils attract the projectiles. This is not correct. They work by repulson (by Lenz's Law, the induced field in the conducting slug repels the coil's field).

    • Whinging about no exact solutions to coilgun parameter values is bogus.

      The authour does handwaving towards the 3-body problem to support his claim that you can't figure out what the best configuration of a coilgun is. These are completely unrelated problems. The 3-body problem is hard because the system a) has no general closed-form solution and b) is chaotic, so you can't even approximate a closed-form solution for many configurations.

      A coilgun, on the other hand, just has more variables than you need. You don't have one optimal coilgun - you have an infinite number of optimal coilguns. Pick some of your parameters to be convenient, and solve for the others.

      It's not hard to calculate how strong the induced field will be in a coilgun, or the force transferred to the projectile. It's also not hard to calculate how a capacitor-driven system will behave (hint: consider the coil's inductance with and without the slug inside it, and you can figure out how the energy transfer works).

    • Energy limitations apply only to military-grade coilguns.

      If you're building a tabletop coilgun, you don't have to worry about energy storage. Just get a good DC supply, set up the coils in parallel with capacitors to get a nice LC tank circuit, and set up a transistor on each coil driven off an extra turn of the coil (or a secondary coil) just as you'd set up an RF signal generator. You're going to put at most a few hundred joules into your projectile (and that's if you're heaving aluminum pipe segments across the street). Exotic solutions are only needed if you're trying to shell a neighbouring city.

    • [He gets most of the switching circuit concerns right, though an ordinary bipolar transistor works fine at tabletop energies, and switching _time_ isn't a problem - even a military weapon can get away with tenth of a millisecond timing for the coils.]

    • Ferromagnetic projectile is just dumb.

      As driving frequency goes up (or pulse length shortens), inductive effects become important. This is how a real coilgun works - it's driven by inductive repulsion of a conducting slug. If you have an iron slug, a) attractive and repulsive forces will fight each other (or you can think of it as induced currents shielding the slug from your applied magnetic field).

      Magnetic slugs only work for tabletop devices with slow firing speeds.

    • A metal sheath is asking for arcing.

      He's using a metal pipe as a guide for the projectile. A closed pipe would shield the inside of the tube just as a conducting projectile shields itself. He cuts a slot through the length of the pipe to avoid this, but you still have very high induced voltages around the pipe. A coilgun that switches at any decent speed with a strong magnetic field will induce currents that arc across this gap.

      If you want a projectile guide, use rails.

      If you want an elegant solution, let the slug move through open air and use secondary coils to adjust the geometry of the magnetic field as the projectile passes through to nudge it back into line if you notice it drifting. But this is not trivial to implement.
    1. Re:Several points look suspicious. by Anonymous Coward · · Score: 0

      You have to moderate the person up, whether you agreee with him or not. He sounds like he has a clue. If he is wrong shoot the fuck out of him in a reply. Sounds like a Physics major to me!

    2. Re:Several points look suspicious. by Anonymous Coward · · Score: 0

      "The authour claims that coilgun coils attract the projectiles. This is not correct. They work by repulson (by Lenz's Law, the induced field in the conducting slug repels the coil's field)."

      You have quite effectively demonstrated that you do not know even the most basic thing about coil guns. Your ignorance oozes out of every word in your post. Coil guns ATTRACT their projectiles. If they repelled them, how the HELL would I place the projectile in the beginning of the coil and have it shoot out the other end, huh? I think it is a fair assumption to say that *I*, having built several dozen Coil Guns with power supplies supplying energy levels in the thousands of joules range and with peak powers of many tens of megawatts, would know how they work. You, in the other hand, don't even know how to spell "LORENTZ", (your illeteracy made you spell it "Lenz") which is the law that governs a RAILGUN's behavior.
      I don't think the rest of your post deserves much further comment since you managed right at the beginning to completely discredit yourself. Still, for the sake of educating anyone who might have gotten the wrong ideas from your misinformed comments, here it goes:
      1- If mathematically simulating a coilgun is so easy, than why don't you go ahead and do it. Actually why don't you show us your coilgun? Oh, don't have one? Geez... And I am the one "cribbing notes from a more informed paper". A paper you wrote I suppose?
      2- "You do not have to worry about energy storage".
      SUUURE... With 6THOUSAND amperes I can impart about 50 joules of kinetic energy into a projectile, but you can manage "A couple hundred joules" with nothing but a "Good DC supply". Must be a DAMN good one because the peak power when my 900V 1.3KJ capacitor bank discharges is 5.4MILLION watts. I don't think I have ever heard of any DC supplies made to deliver that kind of power, but I guess in dreamland where you are from they do.
      3- "Magnetic slugs only work for tabletop devices with slow firing speeds."
      Like the Hypervelocity electromagnetic accelerator in lawrence livermore laboratory, right?
      I feel offended by your reply and I feel it is unfortunate that you had to bestow your vast ignorance upon all of us using my site as an excuse.
      Sam Barros, creator of PowerLabs
      http://www.powerlabs.org

    3. Re:Several points look suspicious. by Lumpy · · Score: 2

      you forgot something important...

      An AC solenoid repels any conductor.
      I would pay BIG money to see a AC coil repel a piece of aluminum, copper or other non-ferrous metal.

      --
      Do not look at laser with remaining good eye.
    4. Re:Several points look suspicious. by Bad_Command · · Score: 1

      Will that be cash or cheque?

      Check out my website to see it.

      The can that gets crushed is aluminum. The AC coil repelling the aluminum generates enough force to crush the can. Likewise with the copper penny.

      If that coil is flat, and if you put a piece of conductive metal on top of it (say, an old aluminum hard drive platter), it will be repelled with tremendous force. In my case, it was repelled with enough force to put a rather large hole in the shop ceiling (1/4" chipboard)...

  64. Just in case by spike+hay · · Score: -1, Redundant

    The Gauss Rifle:
    A Magnetic Linear Accelerator

    This very simple toy uses a magnetic chain reaction to launch a steel marble at a target at high speed. The toy is very simple to build, going together in minutes, and is very simple to understand and explain, and yet fascinating to watch and to use.

    The photo above shows six frames of video showing this toy in action. Each frame shows 1/30th of a second. In the first frame, a steel ball starts rolling towards a magnet taped to a wooden ruler. In the second frame, a second ball can be seen speeding between the rightmost two magnets. By the third frame, the accelerator has sped up so much that the ball that is seen leaving the left side of the device is just a blur as it smashes into the target. One ball, starting at rest, has caused another ball to leave the device at a very high speed.

    Click on image for larger view

    The materials are simple. We need a wooden ruler that has a groove in the top in which a steel ball can roll easily. Any piece of wood or aluminum or brass with a groove will work. We chose the ruler because they are easy to find around the house or at school or at a local stationery store.

    We need some sticky tape. Again, almost any kind will do. Here we use Scotch brand transparent tape, but vinyl electrical tape works just as well.

    We need four magnets. Most any type will do, but the stronger the magnets are, the faster the balls will go. Here we use the super strong gold-plated neodymium-iron-boron magnets we have made available in our catalog for the other projects. They work great.

    We will also need nine steel balls, with a diameter that is a close match to the height of the magnets. We use 5/8 inch diameter nickel plated steel balls from our catalog.

    The only tool we will need is a sharp knife for trimming the tape.

    Click on image for larger view

    We start by taping the first magnet to the ruler at the 2.5 inch mark. The distance is somewhat arbitrary -- we wanted to get all four magnets on a one foot ruler. Feel free to experiment with the spacing later.

    Click on image for larger view

    With the sharp knife, trim off any excess tape. Be careful, since the knife will be strongly attracted to the magnet.

    It is very important that you keep the magnets from jumping together. They are made of a brittle sintered material that shatters like a ceramic. Tape the ruler to the table temporarily, so that it doesn't jump up to the next magnet as you tape the second magnet to the ruler.

    Click on image for larger view

    Continue taping the magnets to the ruler, leaving 2.5 inches between the magnets.

    When all four magnets are taped to the ruler, it is time to load the device with the balls.

    Click on image for larger view

    To the right of each magnet, place two steel balls. Arrange a target to the right of the device, so the ball does not roll down the street and get lost.

    To fire the gun, set a steel ball in the groove to the left of the leftmost magnet. Let the ball go. If it is close enough to the magnet, it will start rolling by itself, and hit the magnet.

    Click on image for larger view

    When the gun fires, it will happen too fast to see. The ball on the right will shoot away from the gun, and hit the target with considerable force. Our one foot long version is designed so the speed is not enough to hurt someone, and you can use your hand or foot as a target.

    How does it do that?

    When you release the first ball, it is attracted to the first magnet. It hits the magnet with a respectable amount of force, and a kinetic energy we will call "1 unit".

    The kinetic energy of the ball is transfered to the magnet, and then to the ball that is touching it on the right, and then to the ball that is touching that one. This transfer of kinetic energy is familiar to billiards players -- when the cue ball hits another ball, the cue ball stops and the other ball speeds off.

    The third ball is now moving with a kinetic energy of 1 unit. But it is moving towards the second magnet. It picks up speed as the second magnet pulls it closer. When it hits the second magnet, it is moving nearly twice as fast as the first ball.

    The third ball hits the magnet, and the fifth ball starts to move with a kinetic energy of 2 units. It speeds up as it nears the third magnet, and hits with of 3 units of kinetic energy. This causes the seventh ball to speed off towards the last magnet. As it gets drawn to the last magnet, it speeds up to 4 units of kinetic energy.

    The kinetic energy is now transfered to the last ball, which speeds off at 4 units, to hit the target.

    Another way of looking at the mechanism

    When the device is all set up and ready to be triggered, we can see that there are four balls that are touching their magnets. These balls are at what physicists call the "ground state". It takes energy to move them away from the magnets.

    But each of these balls has another ball touching it. These second balls are not at the ground state. They are each 5/8ths of an inch from a magnet. They are easier to move than the balls that are touching the magnet.

    If we were to take a ball that was touching a magnet, and pull it away from the magnet until it was 5/8ths of an inch away, we would be adding energy to the ball. The ball would be pulling towards the magnet with some considerable force. We could get the energy back by letting the ball go.

    After the gun has fired, the situation is different. Now each of the balls is touching a magnet. There is one ball on each side of each magnet. Each ball is in its ground state, and has given up the energy that was stored by being 5/8ths of an inch from a magnet. That energy has gone into the last ball, which uses it to destroy the target.

    Speed and kinetic energy

    The kinetic energy of an object is defined as its mass times the square of its velocity. As each magnet pulls on a ball, it adds kinetic energy to the ball linearly.

    But the speed does not add up linearly. If we have 4 magnets, the kinetic energy is 4, but the speed goes up as the square root of the kinetic energy. As we add more magnets, the speed goes up by a smaller amount each time. But the distance the ball will roll, and the damage it causes to what it hits, is a function of the kinetic energy, and thus a function of how many magnets we use.

    We can keep scaling up the gun until the kinetic energy gets so high that the last magnet is shattered by the impact. After that, adding more magnets will not do much good.

    Why a circular track will not be a perpetual motion device

    I have been getting a lot of mail asking what would happen if we made the track circular. Would we get free energy? Would the balls keep accelerating forever?

    I have been tempted to reply with the famous quote: "There are two kinds of people in the world -- those who understand the second law of thermodynamics, and those who don't".

    However, I am not the kind of person to leave an inquiring mind unsatisfied, and it is more productive (and kind) to explain in a little more depth what is going on.

    Suppose you made a circular track, and put two balls after each magnet. When the last ball is released, it encounters a magnet that has two balls at the ground state. There is no energy to be had from this magnet. The ball just bounces back.

    Now suppose you had placed three balls after each magnet. When the last ball is released, it hits a ball that is 5/8ths inch from the magnet. It has not gained much momentum, because most of the momentum gained is in the last half inch as the magnet pulls much stronger on things that are closer. But the ball has enough energy from previous accelerations to release the next ball. However, that ball has less energy than the ball that caused it to release. It may have enough energy to release another ball or two, but each ball that is released has less energy than before, and eventually the chain stops.

    You can show by inductive logic that no matter how many balls you stack in front of each magnet, eventually the system stops.

    To estimate the losses due to heating the balls as they compress when hit, consider a plastic tube standing upright on a table. Place one steel ball at the bottom of the tube. Now drop another ball into the tube, so it hits the ball at the bottom, and bounces back up.

    Now measure how high the ball bounced. If it bounces halfway back up, the losses are 50%. Perform the experiment for yourself with the balls from the Gauss Rifle. How high does your ball bounce? Send me mail with your results.

    --
    If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
  65. This is stupid.. by JPriest · · Score: 1

    because I can't kill people with it. No really, this is like a 6th grade science project.

    --
    Saying Java is nice because it works on all OS's is like saying that anal sex is nice because it works on all genders.
  66. Too bad you're wrong... by Anonymous Coward · · Score: 0

    Sorry to disappoint you, but the military of certain unnameble countries already has projectiles that travel this fast. In fact, the techniques to propel a projectile to 2km/s have been known since the early sixties, and it was done with conventional gas propellant (read: smokeless gunpowder) canon systems.

  67. syndicate by Danse · · Score: 2, Informative

    Old EA game made by Bullfrog. Lots of fun. The gauss gun in that game looked like an oversized pistol IIRC, and it made big explosions.

    --
    It's not enough to bash in heads, you've got to bash in minds. - Captain Hammer
    1. Re:syndicate by negativekarmanow+tm · · Score: 1, Funny

      Well, syndicate was kind of fucked up, with the stats at the end of the mission showing the number of civilian casualties, making it a game to kill every last civilian you meet.

      Or maybe that was just the way I played it...

      --
      No security through obscurity: my password is goatse. Stop me before I troll again.
    2. Re:syndicate by Fesh · · Score: 2

      Man, I loved Syndicate... You killed all the civilians? I always packed a persuadertron... After all, you got money for all the persuaded civilians you had at the end of the mission...

      --
      --Fesh
      Kill -9 'em all, let root@localhost sort 'em out.
    3. Re:syndicate by negativekarmanow+tm · · Score: 0

      Nah, I only persuaded them when I wanted to run them over with a car.

      --
      No security through obscurity: my password is goatse. Stop me before I troll again.
    4. Re:syndicate by Danse · · Score: 1

      Heh. Yeah, I loved the mission where you had to assassinate that guy that was giving the public speech. There was this big crowd of people gathered around him. You just drive by in a car and mow everyone down :)

      --
      It's not enough to bash in heads, you've got to bash in minds. - Captain Hammer
  68. Same teacher? by Davace · · Score: 1

    My physics teacher did the same exact thing. I won't give his name out on slashdot, but he lives in Illinois.

    1. Re:Same teacher? by jsarek · · Score: 1

      Oh Illinois. THAT guy. Your claim is much more believable now.

      ps. I demand that they add a mod category "ridiculously sarcastic"

  69. Large soldering iron for degaussing by Caractacus+Potts · · Score: 3, Informative


    You can also use a large soldering iron or an electric drill to degauss monitors. A soldering iron contains a coil that generates an oscillating magnetic field at 60 Hz. I use this technique to degauss my arcade video games.

    Oh yeah, don't actually touch these things to your monitor! You're just using the magnetic fields from them, not the business ends.

  70. The website will now be shutdown by Kasmiur · · Score: 3, Funny

    {joke}
    For helping terrorist manafactur weapons that could cause mass destruction. Anyone who has viewed this page and learned something from it needs to IMMEDENTLY turn themselves into the local FBI and be detained for trial.

    This message brought to you by the Local FBI and National Security commision.

    {/joke}

    --
    -THIS SPACE FOR RENT!
    1. Re:The website will now be shutdown by Simon+Field · · Score: 1

      You should see the "Plastic Hydrogen Bomb" on the same site: "http://scitoys.com/scitoys/scitoys/echem/echem.ht ml#bomb" ;-) [Author of the Gauss Gun page, and the page touted above] I've gotten some weird email from people who actually think I'm teaching kids how to make thermonuclear weapons. Simon Quellen Field

  71. Rail Guns are more fun! :D by MattRog · · Score: 4, Informative

    Back in high-school for Honors/Advanced Physics I took it upon myself to build a rail-gun, you know - something that could be cool (everyone in high-school thought Quake/Doom was the shiz) and somewhat useful (provided you needed to drive a projectile at 2 to 3 km/sec). The other students were building oh I don't know weird tinker-toys like reverse-osmosis water filtration and a electrolysis something-or-other (a guy the semester before built a tesla-coil using IBC root-beer bottles as capacitors - turned out he had wayyy more capacitance than needed and not enough current) but I wanted to make something that blew stuff up.

    So I went to work assembling materials for the gun.. I didn't worry about the math behind why rail guns worked, all I knew is that it did plenty of damage in Quake. :) So a couple hundred dollars later and I have some copper rails fixed to a base (some wood ;)), a whole lot of 2ga. wire (friend's dad worked for the electric company), and some .9F of capacitors hooked up to provide the juice.
    Two things I learned:
    1) You need a fuckton of capacitance to really achieve massive current (talking hundreds of thousands of Amps needed)
    2) You also need an electronic switch instead of a mechanical switch so you don't lose said Amps to welding the switch to itself.

    .9F of capacitance (after working out the numbers) proved to be far too few amps to do anything but make a whole lot of sparks. Actually I managed to vaporize some of the smaller projectiles with only a small scrap of what was left pitifully dribbled out of the end of the gun. In any rate, after researching further, I found some 5 and 10F capacitors which would've done the job nicely could I have afforded the several thousand dollars it required to buy one.
    So I guess the moral of the story is if you don't have $10M in defense contracts you're not going to get a good rail-gun built since it requires MASSIVE amperage to create a plasma to launch your armature out of the weapon. And Capacitors are not tiny objects, so the likelihood of a 'Eraser'-style railgun are slim to none unless someone magically comes up with a much more compact and higher-capacity capacitor (which can still discharge at 1/1000th or better of a second).

    The problem with a coil gun is that you need massive voltage plus some sizeable amps, which is generally very hard to come by. Your local mains circuit won't provide enough voltage. Although you could push it through a transformer you would need a very large and bulky one, and then you still probably would wind up with not enough amps to do the job. Most capacitors work at low enough voltages that a commodity (e.g. plugs into your regular wall socket) transformer could easily provide it, but achieving enough capacitance is both cost and size prohibitive (ignoring the rail mass loss due to vaporization).
    Stupid Quake. :)

    --

    Thanks,
    --
    Matt
    1. Re:Rail Guns are more fun! :D by Anonymous Coward · · Score: 0

      Hmm, it seems to me that it would be much easier to store your energy in a coil than to store it in capacitors. You let a small voltage build up a large current into a coil, and when the coil current reaches some critical value, you force the coil into series with the railgun coil.

      You certainly have to choose your components carefully!

  72. Let's get the physics straight by pdp11e · · Score: 2, Insightful

    If You observe system in its initial "armed" condition you will find that it is not in its lowest possible energy configuration. Steel balls that are not immediately adjacent to magnets, do have higher potential energy than the balls touching the magnets. After firing, all the balls (except the projectile) are touching the magnets, meaning that the system has lower potential energy. The difference is the kinetic energy of the projectile.

    You are, of course, right when you say that initial energy of the system came from the hands of the person who arranged the balls.

    Now let's get semantics straight.

    >However, none of the fixed magnets imparts energy to the ball

    When the kinetic energy of the particle is enhanced at the expense of the system's potential energy (for the conservative system), the common expression in physics literature is that "field imparted energy to the particle". The expression: energy is "released" is also quite common and it simply means that system is in the configuration with lower potential energy.

    Now let's get you straight.

    >The energy of separating the magnets is not 'released' during this experiement, as the magnets do not move.

    Indeed magnets did not move, but the balls did and the potential energy of the system is lower....

  73. Trial results by Cyberop5 · · Score: 2, Informative
    I got bored so I tried this using Brio magnets (from the old train sets), old rusty pichinko (sp) balls, and a piece of wood trim. The results were less than stellar. but it did work after a few adjustments.

    I was able to get one of the balls off the board a few tiems, but never did it have enough force to knock over a tape dispenser. Maybe quality parts would yield better results.

    --
    Urgo: "I want to live. I want to experience the universe and I want to eat pie!"
    Jack: "Who doesn't??"
  74. Tiffany's Diaper Tales by rapevictim · · Score: -1
    Chapter One

    Hello, My name is Tiffany. I want to share with you all, some things that have happened in my life and this story will be mostly fictional with just a touch of reality in it. I hope you will enjoy my story.

    When I was 8 years old my mommy put me in diapers because I had been wetting the bed. I didn't really mind too much though, because when I laid in bed at night I would fantasize about being a real baby again. My older sister Tammy who was 14 at that time, would sometimes wake me up in the morning when she was getting ready for school. "Tiffy, Is your diaper wet baby?" Tammy asked as I opened my eyes. "Yes, I wet." I replied softly as I rubbed my eyes and began to wake up. Tammy picked me up and laid me on the floor and got some wipies and slid down my rubber pants and unpinned my wet cloth diaper. "Wow you sure did go pee allot!" Tammy said while smiling at me. I blushed and laid there as she cleaned me up and then slid a pair of panties up my legs and helped me get dressed. I went out to go eat breakfast and mom said good morning and stuff and then I got my backpack and went off to school.

    At this point of my life I was only in diapers during the night, and no one really knew that I wanted to be a baby. I did not share this with any of my friends either. I was a bit shy in general anyway. School went like usual, and I got home and played with some friends. Then came dinner time, then bath time, and soon came bedtime. This was a typical day in my life at that time. But, things were about to change.

    One day in May, a couple of my best friends and I were playing. We wanted to play house and I decided I wanted to be the baby. I had told these two girls about my diapers at night and so on, they were ok with it. But they didn't know I had fantasies about being a baby again. Anyway, I walked out to the living room and found my mom ironing clothes. "Mommy, we wanna play house, and I wanna be the baby, can you put me in one of my cloth diapers and rubber pants so I can play the baby." I said. My mother looked at me and said "Can't you just pretend honey?" I shook my head no. "Well ok, I guess you can wear one. Just wait a moment baby I'll come in there and change you into a diaper in a moment. I need to finish what I'm doing here ok sweetie?" My mother said as I ran out of the room back to my room. "So what did she say?" Laura asked. "She said she would put me in a diaper after she finishes ironing." "Oh cool!" I could tell we were going to have lots of fun.

    My mother came in a few minutes later with one of my cloth diapers and some pink rubber pants. She also had some baby powder. She diapered me in front of my friends and we all giggled because it was so funny that I was going to get to be a baby in a real diaper. After she finished she smiled and said, "You girls have fun." We all thanked her and she left the room. "Ok, so lets start, I will be the mommy, and Laura, you can be the big sister, and Tiffany, you are the baby!" Emily said. I smiled and then began to talk in baby talk and crawl around on the floor and Laura, who was playing the part of my older sister, was rolling a ball towards me trying to get me to roll it back. Then Emily came over and held me in her lap. "Its time for baby to take a nap." "No I don't wanna nap" I said in a whiney little baby voice. "Yes you take nap now baby." "otay, but not long nap though." I said as I gave in and fell asleep in her lap.

    I must have really dozed off because suddenly Emily shook me to wake me up. "Um Tiffany, I think you just went potty in your diaper." Emily said as she pointed to my apparently wet diaper. "ut oh, I hope my mommy doesn't get mad at me." "Oh it's ok, I'm sure your mom wont care, I mean you wet them at night and she changes you, so what's the big deal. I mean you are playing baby, so why not wet it." Laura said while smiling at me. "Yeah I guess you are right." "Well lets go see if my mommy will change me.' I got up and waddled out of the room down the hall in my crinkly thick soaking wet diaper.

    "Mommy..." I said shyly. "Yes honey?" "Um... well..." She looked at me and then noticed that I had wet in my diapers. "Oh dear, you peed your diaper. Why did you wet it honey?" "Um, well, because I was being a baby, and well I fell asleep because I was taking a nap, and Emily woke me up and told me I was wet." "Well in that case since you all are playing baby, go get one of your diapers and let Emily & Laura change it for you." mom said teasingly. I nodded and then waddled back into my room, crinkling all the way down the hall.

    "So what did she say?" Emily asked. "She said that since we were playing house, that one of you has to change my diaper" I blushed. "Ewww yuck!", Laura said, "I'm not changing that thing." I started to cry. "I need my diaper changed, its all wet. Please help me?" I cried. "Oh ok you big baby, lay down and I'll do it.", Emily said. I lay on the floor and Emily changed me out of my wet diaper and into another dry one. Laura just looked at her. "Maybe we shouldn't play baby any more. What if she wets this one too?" "Well then we just will have to quit playing and put her back in big girl panties", Emily replied. I just laid on the floor on my back with my diaper on but waiting for Emily to pull up my rubber pants and tuck my diaper in. Finally she did and we resumed playing. This time I stayed dry.

    Laura & Emily went home and I stayed in my room and played with some toys. Mom called me to dinner. I was still in my diaper, but hadn't gone potty in it since that last time when I was changed. I waddled out to the dinner table. By this time Tammy was just pulling in the driveway. She always got home right before dinner because of cheer leading practice. Dad usually picked her up on the way home from work. As I was helping my mom set the table both dad and Tammy came in.

    "Tiffany honey, what are you doing in your diapers?" dad asked. I looked at him and blushed, "Um, me and my friends were playing house and I was the baby, I... I forgot I was still wearing them." "Aww you look so cute!" Tammy said as she walked back to her room to change. As we all sat down for dinner I was halfway through eating when I had to go number 2. "Um mommy", I said quietly. "Yes baby?" "Um... I gotta go poo, um can you help me, I'm still in this diaper, I don't know how to get it off.", I said in an urgent tone that made it noticeable that I really had to go. "Oh honey, we are eating now, Why don't you just go in the diaper and I will change you after dinner" She smiled at me. I started to cry a little, "But mommy, I don't wanna go poopoo in the diaper, I am only used to wetting, I don't wanna do number two." My father interrupted me and said, "Oh baby, just do it in your diapers and be quiet, you were the one who wanted to wear them in the first place. Babies go poop in their diapers, so just go, ok honey?" I began to cry and I put my head down and cried as I totally filled my diaper with a big poopy load. Then mom picked me up and carried me to the bathroom and changed me, but not into panties, but another diaper. "Mommy, why another diaper?" "Because, I can tell you like being babied, and I also saw what you wrote in your diary about how you want to be a baby. I know I shouldn't have read it, but you left it out and I happened to notice it when I was cleaning the other day. Honey, we don't mind if you want to be a baby. Its ok." I stopped crying. My mom hugged me and patted my diaper bottom. "But honey, you will have to wear them all the time. You will wear them to school, at home, or wherever you go. You cannot use the potty anymore since your a baby... ok?" I nodded and agreed to it.

    As we came back out to the dinner table everyone smiled. Apparently mom and dad had talked about this earlier and while I was being changed, Dad talked to Tammy about it. We had desert and then mom asked Tammy if she would go give me a bath since I'm a baby now. I was sort of shy about all this, but I knew it was what I had always wanted. I wondered what other kids would say, but I just knew this was worth it. I was not going to fight this. "Come on you big baby, lets get you cleaned up." Tammy said as she motioned for me to come over to her and fallow her to the bathroom.

    She bathed me and let me splash in the water for a little bit and play with my old rubber ducky I had when I was a little girl. She got me out of the tub and dried me off. She diapered me and then took me out the living room. We watched cartoons on TV. Then Mom said it was time for me to go to bed since I am a baby I need my sleep. I didn't mind, because I was already tired. It had been a very busy day. As my mother tucked me in she smiled at me and said, "Honey I know that you have wanted this for a long time, and well, I have to admit, so have I. I mean, I just want you to stay my little baby girl forever honey." She kissed me goodnight and dad came in shortly after and kissed me good night and said "Nite nite little baby, sleep well and sweet dreams." I started to drift off to sleep when Tammy came in and whispered, "Hey, Tiffy?" "Yes Tammy?" "I think you really make a cute baby and I love you and I want you to know that if anyone picks on you at school, I will beat them up for you. Now go to sleep and I'll see you in the morning ok?" I smiled as she left the room and closed the door. I once again drifted off to sleep.

  75. Where to get those magnets by laeraun2 · · Score: 2, Informative

    I remeber reading a review of those cool rare earth magnets on Dan's Data.

    The link to the article is here The link for where to cool magnets on his page is here

    Now we just have to wait for a slashdotter to build a large version of this and use it to smash some watermelons :)

    --
    Error: Erection reset by beer.
  76. WWBOFHD? by Pope+Slackman · · Score: 2

    The editors at Slashdot.org are about to link to your site in about 4 hours. You now have three options: [...]

    Presented with those options, the bastard admin would choose option 4:

    Redirect anyone with "slashdot.org" in the referrer header to another site...like say, goatse.cx...

    C-X C-S

  77. Don't be messing! by paul.dunne · · Score: 2

    Mind now, or you'll take someone's eye out with that!

  78. Neodymium Magnets by gaussboy · · Score: 1

    Speaking of Gauss.. I just started a company called Gaussboys We sell NdFeB magnets. Yeah the really strong kind that will give you blood blisters, or worse. We only have a few disk shapes now, but more are on the way. So, if you're wondering where to get this stuff. Come talk to me.

    1. Re:Neodymium Magnets by Whomp-Ass · · Score: 1

      How in the hell does a magnet give you a bloodblister?

    2. Re:Neodymium Magnets by Drgnkght · · Score: 1

      Human blood contains iron.

    3. Re:Neodymium Magnets by ErikZ · · Score: 1


      Woah! Nice site! You should link your combos to some prices though.

      I don't have any disposable income at this time, but you're bookmarked.

      The picture where you're hanging the hammer is impressive. You might want to go with that. I'd perfer to use that instead of using pegboard to hold up my tools.

      Any ideas on how to get a metal board board?

      --
      Democrats or Republicans. They are both taking us to the same place and they are not afraid of us anymore.
  79. I need one for my collection by Icemaann · · Score: 1

    Id like to have one of the mentioned 2K/s versions sitting next to me Spud Gun :)

    --

    Icemaann
    http://www.nugg.org
  80. Why do people still use Angelfire??? by ringbarer · · Score: -1

    It's one of the worst fucking free web hosting sites in the world.

    Geocities is barely better these days, what with the traffic cap and all.

    Somethings in life are worth paying for, like web space and prostitutes. Others? Well, I know one thing I'm not paying for...

    --
    "Why did they cancel my favorite Sci-Fi show? I downloaded ALL the episodes!"
    1. Re:Why do people still use Angelfire??? by $uperjay · · Score: 0, Offtopic

      Come April 1st, Geocities will no longer support FTP. So, it's now just as bad as Angelfire.

      The internet is dead, I tell you! Woe! Woe!

    2. Re:Why do people still use Angelfire??? by Drgnkght · · Score: 1

      Actually it will. But only if you pay them. :-(

  81. Great by Anonymous Coward · · Score: 0

    Now we have to worry about out kids getting railed at school.

    "Boy you're ass is gonna get fragged by the jungly gym after school!"

  82. That's nice, but with these... by gabba_gabba_hey · · Score: 1
    Hmm, well they may be able to knock over a tape dispenser with those little magnets, but with these you could probably do some serious damage ;)

  83. Atari joystick hooked up to a mounted turret by Anonymous Coward · · Score: 0

    Back in August of last year, I was playing with making a cheap robotic turret. I was able to isolate the 5v interface coming from an atari joystick(or computer parallel port), but was unable to take it to control a car battery's voltage.... It would seem like such a fucking easy task to use an on/off 5v current to control the on/off current of another, but I couldn't figure out how and I just ended up welding some radio shack parts.

  84. Memories.... by mancuskc · · Score: 1

    Reminds me of the crossbow I made when I was 12 - out of a car leaf spring and a bit of 4x2. Had to use a car jack to tension it. Copied the trigger release out of a library book and made it in metal at school in CDT.

    Mom took it off me when I fired a 2 foot long 1/4 inch threaded bar through the garage wall.

    Now why did she have to go and do that? I couldn't pick the thing up - it was nearly 4 feet long!

    --
    When I were your age, all round here were fields...
  85. I confirm by clarkie.mg · · Score: 2

    One boy at the university I studied electricity, one year younger than me, died while disassembling a TV.

    Yes, you read well, he died because of remanent current in the electrical circuit (capacitor+inductive).

    When I was younger, I decided to wire a 12V DC engine to the 220V AC network. Oh and I had opened the engine. Guess what, it burned and the explosion burned my face (though lightly).

    Take care.

    --
    Men are born ignorant, not stupid; they are made stupid by education. Bertrand Russel
  86. A Real Railgun by HellKrisp · · Score: 4, Informative

    If you want to know how to build a REAL railgun, try this. Admittedly, its a bit harder to build.

  87. Cool by ZigMonty · · Score: 2

    The whole site is cool, browse around. I love the hydrogen bomb (chemical not nuclear). The levitating magnet's cool too. Now, to build that gun...

  88. Prepare to be disappointed... by Anonymous Coward · · Score: 0


    Be let down here, and here, and here, and here, and here, and here...

  89. gauss projectiles by Anonymous Coward · · Score: 1, Insightful

    First, Syndicate realy rocked. Second, I don't think you are restricted to solid metal-bodies as projectiles for your gauss-guns. Perhaps you could also use the gun to (silently!) propell a grenade which then explodes on impact. It would just need to contain enough iron (or whatever) to be accelerated by the coils. Can't remember the Syndicate-details though.

  90. Better gauss gun by joshamania · · Score: 2

    When in high school, a buddy of mine and I made a magnetic gun of sorts by taking magnet wire (think 24 guage, laminated, solid core wire) and wrapping it around a piece of 1/2 inch pvc pipe about eight times or so. Then, by running a very powerful DC current through the wire, it turned tha apparatus into a very powerful solenoid, of sorts. If you put a projectile in one end, turned on the power, and disconnected it before the projectile reached the middle of the tube, it would continue out the other side of the tube for some distance. I think the final version was able to shoot a small wood screw about 30 feet or so...

  91. homemade by fabiolrs · · Score: 1

    Is there a tutorial on how to build my own CounterStrike like AWP (sniper) gun????? :))

    --
    Fabio - Sumare/Sao Paulo/Brazil/South America/Earth/Solar System/Milky Way/Universe
    http://www.morroida.com.br
  92. Here's how to see the site by eagl · · Score: 1

    First go to the home page, then click on the link. Don't try to go directly to the page from here.

    Dunno why it matters, but I got the page on the first try by first hitting the web site homepage then clicking on the link.

  93. degaussing wand exists by Anonymous Coward · · Score: 0

    need to degauss a monitor w/o a degauss button?
    does your degauss button not undo a particularly heinous injury?

    Degaussing wands exist for this type of situation. You can buy one. Or, you can make one. A ferrous rod wrapped with wire (an electromagnet) hooked up to an amplifier, hooked up to a tone generator set to 20 hz.

    Have fun!

  94. Neal Stephenson's by Funkeriffic+Toad · · Score: 1

    Anyone read The Big U by Neal Stephenson? I mention this only because his other work is obviously immensely popular among /.ers. This old book from his college days includes a very large-scale rail-gun project with results that you'll just have to read the book to find out about...;)

    I highly recommend it.

  95. How to Build a (cheap, simple) Railgun by Abraxis · · Score: 1

    WARNING: Do not try this at home unless you are smart enough to not kill yourself and those around you.

    A physics buddy of mine made a rail gun for his senior project. Ammunition: Pennies. I believe only older pennies worked. Basically, he had two metal rails attached to a flat, smooth surface. The rails were parallel, and were exactly the width of a penny apart. They were shaved off a little at one end so a penny could be easily slid in between the rails.

    There was a BIG capacitor, and a power supply to charge it with. It was wired so that it could be easily switched between two modes: charging and firing. In charge mode, the power supply charged the capacitor. In firing mode, the capacitor has one terminal connected to each rail (and there was a "safety" switch between on of the terminals and one of the rails).

    The firing process consisted of charging the capacitor, then switching into firing mode.
    The penny was then put on the flat surface flat surface near the end of the rails that had been tapered. The safety switch was closed, then using some sort of insulator, the penny was quickly shoved in between the rails completing a circuit: capactitor to rail to penny to rail back to capacitor. The result: A loud "crack".. some sparkage... and the penny was sent flying across the room... sometimes getting a good thirty feet of distance before hitting the ground (launched off of a table).

    The penny tended to jump up out of the rails and fly not perfectly straight (often tumbling end over end), so the design could be impoved upon. Another problem was that the penny would melt a bit and leave residue on the rails, which had to be scraped off (and/or the rails turned over so that an unused surface contacted with the penny).

    Definately not a practical device to go around fragging your enemies with (not even portable!), but definately a cool relatively low budget project. And when it's done you can say to all your friends: "Hey, want to come see my railgun?".

  96. The FuckSlashdotNow Report issue #1: Nested Mode by FuckSlashdotNow · · Score: -1, Redundant
    **BEGIN**

    This is the first issue of The FuckSlashdotNow Report, and more installments will hopefully be written on a regular basis. Thanks for reading, friends, and keep watching the skies! Permission is granted to reproduce this message in any form, as long as the entire message is kept intact, from the **BEGIN** to the *EOT*

    ISSUE 1

    With the announcement of Slashdot subscriptions, the question becomes "what is the most fucking effective way to fuck Slashdot out of as much fucking money as fucking possible?"

    Nested mode.

    Nested mode draws a monumental amount of bandwidth compared to Threaded mode, with fewer page views (for subscribers) or banner ads (for non-subscribers)

    Let's say that the first page of comments on a heavily-discussed story in threaded mode is 100KB in size. A person reading that story will read some of the sub-level replies to those comments comments, but not all, so let's say he pulls perhaps 200KB of bandwidth maximum, and it will cost him many page views/banner ads. Now, someone viewing that same page in nested mode is entirely likely to pull 500-1000KB, with only a single page view or banner ad. More cost to Slashdot, less income to Slashdot, therefore less PROFIT for Slashdot.

    This goes without saying, but we also need to set our thresholds to -1 (yours IS already set to -1, right?), set our "max comment size" to very high (so that gigantic garbage comments display in full), as well as setting "Limit" very high aslo. Crapflooders need to focus more on posting replies to high-rated or early-posted comments instead of (or in addition to) posting top-level comments, because many people don't bother visiting the second page of comments when there's more than one. And we all need to use Junkbuster, of course.

    Let's summarize:

    Threaded mode:
    Less bandwidth (small cost for Slashdot)
    More page views/ads (large income for Slashdot)

    small cost + large income = PROFIT

    Nested mode:
    More bandwidth (large cost for Slashdot)
    Less page views/ads (small income for Slashdot)

    large cost + small income = FUCKED

    Now, the question becomes, can we cost them more money by subscribing, or by not subscribing? I'd be more than happy to throw $50 at Slashdot if by creative page-loading I could cause it to cost them $100 -- I'd be out $50, but so would they, so I think it'd be worth it. It would definitely do more for the world than throwing $50 at those gay starving African children in Africa. But can we cost them more money by subscribing or by not subscribing?

    Most large-scale bandwidth providers charge a few dollars or so per gigabyte. Let's be generous, and say that Slashdot pays $5 per gigabyte. With subscriptions, you pay $5 for 1000 pageviews. Unless your 1000 pageviews average 1.024MB each, Slashdot isn't meeting expenses, they're making a profit. Subscribers will not only be paying their own way, they'll be subsidizing non-subscribers. Slashdot is lying to subscribers, and it's important that potential subscribers know this.

    So basically, if you subscribe to Slashdot it's harder to fuck them than if you don't subscribe. So don't subscribe. And encourage your friends not to subscribe

    Although this particular message is aimed at trolls / crapflooders / culture jammers / anarchists / discordianists / etc, it's important that we recruit the "normal users" to this crusade without them even knowing what our true purpose is -- just educate them that they'll get better value for their money if they use nested mode (much fewer pageviews than threaded mode, thus their subscription lasts longer), without pointing out to them that this'll also spike Slashdot's bandwidth usage.

    In short, encourage subscribes to use NESTED MODE and to lower their thresholds to cut down on the pageviews they spend (actually to increase Slashdot's bandwidth usage)

    Once subscribers realize that they can cut their page views down to a fraction by always using only nested mode, Slashdot's bandwidth usage will start to rise and they'll be forced to use larger and more intrusive advertisements to generate more income or make the site even crappier to drive people away to reduce expenses, or both. More intrusive ads will lead to more people joinining the FuckSlashdotNow campaign, or to quit Slashdot, or to merely Junkbuster the ads, fucking Slashdot's income stream further.

    Summary:

    Trolls / crapflooders / culture jammers / etc / should do this:

    1. Junkbuster
    2. Use Nested mode, -1 threshold
    3. Set max comment size very high.
    4. Not subscribe
    5. Load as many pages as possible
    6. Consume as much bandwidth as possible
    7 Load as few advertisements as possible
    8. Recruit others to the cause
    9. Re-post this message to every thread
    10. Rate this comment up whenever you see it posted
    11. Stay tuned for more updates.

    We should (covertly) encourage non-subscribing normal users to do the following:

    1. Not subscribe, because it's not a good value for their money.
    2. Use Junkbuster to block banner ads.

    We should (covertly) encourage subscribing normal users to do the following:

    1. Use Nested mode for the duration of their subscription, so that they'll spend fewer pageviews and get better value for their money.
    2. Not resubscribe.

    Thanks for reading this first issue of The FuckSlashdotNow Report! I'm currently soliticing ideas for upcoming issues; please e-mail me (e-mail address is in profile) with any comments or suggestions!

    ur VARY aprctd fr rdng ths msg, pls fix thx!!!

    *EOT*

  97. buy some extra bandwidth... by AndyChrist · · Score: 1

    And prepare for the slashdot effect on your bank account.

  98. don't build railguns! by crystalplague · · Score: 1

    I can see it now. A sizeable precentage of slashdotters starts building these super massive rail guns. One by one, they power them on. Eventually hundreds of these are drawing thousands of volts and amps.

    Bam! The enitre power grid is slashdotted.

  99. Military rail guns meet military EMPs. . . by Ayatollah · · Score: 1

    If the EMP is really being developed (and it is), these sorts of weapons may become useless. Unless we have them, and coordinate our attacks well. Otherwise, we're back to WWI fighting: old school artillery, guns, and gas (meaning chem and bio). No computers, no electronics. Even the aircraft could be affected. This could be a major setback.

    1. Re:Military rail guns meet military EMPs. . . by Fixer · · Score: 1

      TEMPEST shielding, look it up. It's to prevent snooping via correlating waste EMF radiation, but it also works nicely to stop an EMP. Also, look up the Faraday cage, and apply that to the concept of a EMP weapon.

      --
      "Avast! Prepare for the rodgering!" THWACK! "Arrr.. me nards.."
  100. thats not why you get blood blisters by Anonymous Coward · · Score: 0

    you get blood blisters from the magnet leaping together and piching you REAL hard.

  101. Ordering from scitoys.com is insecure by jwag · · Score: 1

    If you are tempted to order the Gauss Gun Kit from scitoys.com be aware that your credit card number will be transmitted over an insecure connection.

    --
    -- jwag
  102. Addendum: Second coilgun approach. by Christopher+Thomas · · Score: 2

    After doing further research, I've come across a second operating principle used to make coilguns, which is closer to what the original poster described.

    As a conductor resists changes to the local magnetic field (Lenz's Law, cited above), if you set up a moving magnetic field, the projectile will tend to follow it.

    Note that the projectile is not "attracted into the coil", as the original article stated. Rather, if you're turning coils on and off in sequence along the gun, the projectile will be repelled by the moving field as it approaches, and dragged along with it (attracted) as it passes. The projectile *won't* just follow along with the first pulse in the moving field, either - it's just tugged briefly in the same direction. You'd have to send a train of moving field pulses over it to bring it up to the speed of the train, and it'll never quite get there (as the speed of the projectile approaches that of the moving pulse train, the pulses pass with lower frequency, so the projectile's efficiency as an inductor drops).

    You don't gain much drift-resistance, either. While the projectile is no longer actively perturbed off-axis (as with the previous style of coilgun I described), nothing keeps it on the axis either. You still need active correction (or rails).

    You're also wasting more power, because you have to keep many coils (those around the projectile) oscillating instead of just the coil behind the projectile.

    This coilgun still does not require a ferromagnetic projectile, though ferromagnetism doesn't actively harm this type of gun.

  103. Anyone notice anything disturbing? by ugotshank · · Score: 1
    Private: "Sir! We've just spotted a magnetic imbalance in Northern Afghanistan."
    Officer: "Don't worry about that. Gauss guns don't work with metric rulers."

    But seriously, what's with that boxcutter? I thought the training manuals we found are still classified as classified.

    --
    "This is the only sane ward in the whole hospital. Everybody is crazy but us. This is probably the only sane ward in the
  104. Re:A Real Railgun - done as class project by Anonymous Coward · · Score: 0

    Alternately, check out the class project version here.

    I want to take the class that has students creating these kinds of toys for credit.

  105. Re:Spud Gun fuel by maddogsparky · · Score: 1
    Gasoline. Much cheaper and more umph than hair spray.

    Don't use too much or it will disolve the PVC.

    --
    science is a religion
  106. College project by Special+Ed · · Score: 1

    This reminds me of a friend I had at the US Naval Academy. As an Electrical Engineer he chose to work on a Rail Gun as his Senior Design Project.

    About 3/4th of the way through the semester he came to my room raving about the "Break through" he had that day.

    The next morning he went back to the lab only to find it completely cleaned out. All of his notes had been confiscated. He was told that the project was now classified "SECRET." As we, lowly midshipmen, only held "CONFIDENTIAL" clearances, he could no longer access his own work!

    He got an "A" on the project.

  107. What if degaussing doesn't work? by GPS+Pilot · · Score: 1

    I was playing with an extremely strong magnet, using it to make funky distortions in my comuputer monitor.

    When I took the magnet away, a lot of discolorations in the screen remained. "No problem," I thought, "I'll just hit the degauss button."

    Well degaussing only removed about half of the problem. The image still looks pretty bad and discolored.

    Any suggestions how to fix it?

    --
    That that is is that that that that is not is not.