Slashdot Mirror
Small Change, and Other Physics Fun
fishy jew writes "Ever want an easy way to make your 'small change' even smaller? Well, Bert Hickman has it - mix a home-brewed machine, 6.5 kiloJoules, and 100,000 Amps of current! On his website, he has descriptions and pictures of his many exploits with large quantities of electricity, notably including shrinking coins, building a Tesla coil, creating Lichtenberg figures (chaotic sculpture), and more! He has extensively outlined the equipment, procedure, and results for each of his experiments, and included many pretty pictures, too. Here are Google caches for when the site gets /.'ed: Main Page, Shrinking Coins, Tesla Coil, and Lichtenberg Figures."
There is a cool Popular Science article for more information.
Now go buy some coins to fund Bert's efforts!
Remember... ZG9uJ3QgZm9yZ2V0IHRvIGRyaW5rIHlvdXIgb3ZhbHRpbmU=
Have redirected some of that current into getting a more powerful network connection.
Apparently the slashdot effect is a kind of physics fun he didn't account for...
Intolerance for ambiguity is the mark of the authoritarian personality.
Doesnt do anything, because it doesnt cache the pictures. And thats the largest problems of slashdoting. I think slashdot should try to temp mirror the pages for the first few hours it goes up, if its a small site.
snowulf.com
I wonder how much I'd have to pay for an ad cleverly disguised as a slashdot main story.
No posts yet, but already slashdotted.
Actually, though, I have seen his page before. really cool toys, but strikes me as something most of us would probably not want to play with.
Worry about the health risks of frequent cell phone use? Doesn't even come close to the RF this sucker puts off. Not to mention ozone and the very real risk of simple death from electrocution...
If it gets enough hits, will it become small enough to fit in a blade system?
tesla coils are really cool. a friend and i once took a 30,000 volt capacitor bank, a homemade tesla coil and a homemade spark gap and liquified my deodorant.
his garage smelled great for a few months.
also, any time we'd point the tesla coil towards his neighbors house, they'd lose TV reception.
for the love of god put in a working link
I used to have a cool sig, back when I cared
Electrons moving in a wire exert a magnetic force.
A lot of electrons moving in a wire exert a lot of magnetic force.
If you use coiled wires, you get a cylindrical magnetic field.
If you put a coin inside a coiled wire with a lot of electrons moving through it, it gets smooshed.
Do daemons dream of electric sleep()?
See Sam Barros' Powerlabs for similar stuff - the guy has got a lot of very cool and realy interesting stuff.
Especially interesting are his high-voltage stuff.
Vote for a Man, Vote for Bush!
Not a liberatarian flipflop hippie.
With some slight modifications, this technique could be used to shrink the national debt.
* Theory of Operation
* Results
* EM Field Theory and Wire Fragmentation?
* Isn't Defacing Money a Federal Crime?
* So Who Invented this Crazy Device?
* References
Theory of Operation:
The Quarter Shrinker uses a technique called high velocity electromagnetic metal forming, or "Magneforming". This technique was originally developed by the aerospace industry in conjunction with NASA, and has been popularized by Aerovox, Grumman, and Maxwell. It involves quickly discharging a high energy capacitor bank through a work coil to generate a very powerful and rapidly changing magnetic field which then "forms" the metal to be fabricated. While it works best with metals of relatively high electrical conductivity such as copper or aluminum alloys, it will work to a more limited extent with poorer conductors such as sheet steel.
In my current system, I charge up a large capacitor bank consisting of a number of large capacitors, each weighing about 165 pounds and about 30" high x 14" wide x 8" thick. A High Voltage relay is used to connect the caps either to a high voltage DC charging supply, or to a high power bleeder resistor chain. A 15 kV 60 mA transformer and a set of 40 kV rectifiers provide the DC charging voltage for the capacitor bank. The primary of the transformer can be overdriven to 140 volts via a variable autotransformer to speed up the charging process. The electrical energy stored in the capacitor bank is proportional to the square of the bank voltage, and the degree of "shrinking" force is directly proportional to the capacitor bank's energy.
The charged capacitor bank is quickly discharged through a single layer work coil made of heavy magnet wire. The coin is held firmly in the center of the coil by a pair of dowel rods so that it's axis of rotation is parallel to the centerline of the coil. This constrains the coin from twisting, and also helps balance the forces wanting to eject it from inside the coil. The two ends of the coil are stripped of insulation and firmly bolted to heavy copper bus bars. The high voltage "switch" that connects the capacitor bank to the work coil is actually a high power triggerable spark gap, called a "trigatron". The main gap electrodes are solid brass, 2.5" in diameter. One of the electrodes is drilled and tapped to hold the triggering electrode (actually a modified spark plug). A triggered spark gap is the only affordable device that can hold off the high voltage and then reliably and efficiently switch the high currents involved in the shrinking process (70,000 to over 100,000 amperes).
The trigatron is fired by applying a high voltage (~40 kV) pulse to the trigger electrode, which then causes the main gap in the trigatron to ionize and fire. Once the main gap fires, current rapidly climbs in the work coil, the rate of change (di/dt) being of the order of 4-5 billion amperes/second. The natural resonant frequency of the LC circuit formed by the capacitor bank and work coil is of the order of 8-12 kHz. Through transformer action, a huge circulating current is induced in the coin, but because of skin effect, this current is confined to the outermost rim of the coin, typically penetrating to a depth of less than 0.050". In clad coins more of this circulating current flows through the better conducting copper center of the clad sandwich than in the outer layers. The coin and work coil magnetic fields oppose each other (Lenz's Law), resulting in tremendous repulsion forces between the work coil and the rim of the coin. The circulating current in the rim of the coin actually prevents the rapidly increasing magnetic field of the work coil from penetrating the interior of the coin.
The large current that's induced into the outer rim of the coin can reach a million amperes or more! The initial bank energy is typically in the range of 3,500 - 8,500 Joules (or watt-seconds) but it is being discharged in microseconds. As a result, the instantaneous power is quite large, and for a brief instant is roughly
Check out the picture and prices of the some of his work on ebay
Try slashdoting that!
Please Contact Me me to discuss YOUR custom shrinking needs!
Ah, now this is a welcome relief from all those spammers who seem to think I always need to make things bigger!
What happens is the coin ends up _thicker_ than before. Because it is thicker, the coin in turn becomes smaller. The mass is indeed the same before and after.
There is no exotic atomic manipulation going on. Not that people have tried (aka alchemy).
Here are his ebay auctions
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
Magneforming is just another less-common metalworking techniques. Others include hydroforming, water jet cutting, spinning, and blowing.
Better than a mirror: The Wayback Machine!
Try looking here.
Or here.
The archives are kind of old (pre 2004) but they seem to have some of the information.
Huh?
I'm happy to see the site finally get the news for nerds treatment it deserves
:-)
Yeah! That's even got a catchy ring to it... From now on, when we want to bring a site to its knees, we'll give it the news for nerds treatment.
Here is a link to a site on Tesla Coils, since so many of you seem to be interested in them.
http://www.eskimo.com/~billb/
Fly me to the moon Let me sing among those stars Let me see what spring is like On jupiter and mars
Looks like the US Air Force's Rome Air Development Center thinks they have a patent on it. Am I the only one who thinks "United States of America as represented by the Secretary of the Air Force" should not be a valid patent assignee?
Slashdot - News for Herds. Stuff that Splatters.