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Magnetic Fluids
Polo writes: "Remember those magnetic sculpture things you can buy at the mall where these small metal pieces stay in one shape. Imagine doing that with Ferrofluids.
This is just too cool. Dan is the nerd's nerd." Well, can't get any higher praise that that, I suppose. :) I have a couple of neodymium magnets and yes, they are much fun. Never played with magnetic fluid though.
site already slashdotted. dont see any posts yet
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Japanese artists Sachiko Kodama and Minako Takeno did an art piece displayed at SIGGRAPH using ferrofluids. Memepool had some links about this back in august.
LS
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Ferrofluids have been used in magnetic clutches. You have two plates facing each other with vanes on them. Put them in a ferrofluid tank. When the magnetic field is absent, either shaft will spin freely without effecting the other. Add a magnetic field and WHAM, the shafts are locked together. I seem to remember there being a problem getting a decent amount of shear strength though. There was an article on this in Scientific American a few years back in the Amateur Scientist column.
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The "nerd's nerd" couldn't handle three measly hits? This has to be a "slashdotting" record. ;-)
crib
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At Berkeley, they use magnetic fluids to control movement of underground fluids without any contact. Interesting stuff. For an introduction to ferrofluids, see University of Wisconsin's excellent article.
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check this link. It's the first link on the page (which is unreachable by now).
I have a couple of neodymium magnets and yes, they are much fun. Never played with magnetic fluid though.
That explains the form errors trying to reply to this story.
Umm, Michael? Could you keep your fscking magnets away from the fscking servers? Thanks.
Soko
"Depression is merely anger without enthusiasm." - Anonymous
Check out this cool picture from Science Friday.
And a meatspace link: check out ferrofluids for yourself at the exploratorium -- if the exhibit is still there (it was maybe 4 years ago, upstairs), they have a tank of ferrofluid (with I think a lighter different-colored fluid floating on top). Pressing the buttons activates different electromagnets under the fluid, and it forms bumps on the surface (maybe protruding through the different colored liquid, as in the picture above, if I remember right). It's neat to see the surface of a liquid that is not flat, yet not moving. The exploratorium is well worth the visit if you're in the SF bay area.
HIV Crosses Species Barrier... into Muppets
Anyone know how many turns of a coil runnig at 1Amp you'd need to make a 1cm by 1cm crosssection of this sort of stuff remain rigid against a newton of shear?
anarcho-roboticist [lopster incomplete: 6.5% of 2.5GB]
I got the article in time. The pics not.
find it here
Never played with magnetic fluid though.
Michael can't have been to a science museum of late. I can remeber seeing small tanks of magnetic fluid that allow you to wave magnets around near them to see what happes in museums a couple of years ago.
Oh, and Wired magazine had a lovely picture of magnetic fluid in a beautiful state that was to be shown at Siggraph (See wired for article check here for video)
-- Mike
Lee Valley Tools, besides being a generally cool place with some delightful woodworking tools, has spherical magnets.
And, no, to presuppose the silly question I was asked earlier, of course one of the poles isn't in the centre of the magnet. If it were, how the hell would the flux lines get to the outside?!
These would be the equivalent of a bar magnet lathed spherical, allowing them to roll around and do other neat shit.
FWIW, Lee Valley also has awesome rare-earth disc magnets. I've got a handful of them. They can suck through a good 2" of wood. Damn near impossible to get off the fridge door. Does nasty shit to any nearby wallets, too. And don't even think about letting them near your monitor.
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just wait until this hits the infomercials.. they'll probably have some sort of offer for "therapeutic gel" that you bathe in. just toss your favorite electrical appliance in, and voila!
Actually I used to use the stuff for educational purposes and it is gross ass hell. Gets on everything and wont wash off. Fun for the first 30 seconds.
I got the video downloaded just in time...
here
---- Breakbeats are not just music...they're the soundtrack for my life.
http://homepage.mac.com/crayz/magnets/magnets.htm
Thank Apple for the bandwidth
That fella has some seriously fucked up links.
Look for the one where he talks about using magnets as body mods...follow it and see what the twins are doing.
How about amputation and reattachment, parts swapping between the two?
Photoshop, I hope, but I dunno.
Writers imply. Readers infer.
Well this week we've had revolutionary discoveries with new magnetic solids, and now magnetic liquids. Does this mean that they'll discover a magnetic gas next? It would certainly help in those awkward situations where you just can't hold your fart anymore.
Kurdt
I'm not anti-social. Just pro-technology.
When is Slashdot gonna start caching interesting story links? Even just for a few hours...
The /. magnetic influence apparently caused an influx of charges to decimate the site.
The above post is an editorial, the poster cannot and will not be held responsible for all or in part for it's contents
saw a presentation on magnetic fluids a few years ago at school... tons of applications because the viscosity can change with the magnetic field applied, so basically lots of active damping. I've seen applications such as bike suspensions to gun recoil to washing machines.
another cool trick is to put the stuff in a suringe that is connected to a second suringe, fluid will move back and forth with the plunger until a magnet is place near by then it gets
We had this when I was little. We called it mercury. Only this time, it won't make us like a the mad hatter.
Mod point free since 2001
Ah... We killed him already! Get a mirror up quick!
--- At my sig, unleash hell.
Anyone tried getting someone to drink some of this liquid and trying to catch them with a large magnet ;). On the serious side, Dan's data appears to have ben slashdotted.
Don't call my crazy, that's what they called me back in the home!
It shows how far science has come - we've finally found a replacement for that sticky (cornflour and water) goo kids play with, which solidifies under pressure - now they don't even have to move their arms! laziness abounds!
Fluids influenced by magnets have been around for a while.
One of the problems facing the space program in its earliest days was how to re-fire liquid fueled rockets in a weightless environment. If you think about it, just exactly how do you get the fluids in a tank half full of rocket fuel to take a position over and in the sump of the tank so the pumps can supply reliable measures of fuel and oxidizer to the engines combustion chamber.
The innovative solution was to mix the fuel and oxidizer with a ferrous based additive so that a large magnet at the sump of the tank would draw the fuel and oxidizer to the sump. This isn't a magnetic fluid but it is one of the ingenious solutions to a myriad of engineering challenges facing our space program.
A few friends and I bought a large bottle of the stuff, it's pretty neat to play with along with some magnets, but you need some SERIOUS power to get any real decent results, initially we were messing around with some discarded large speaker magnets and voice coils (fixed magnetic power). We went so far as to have ordered some higher power electromagnets and some extra hardware to control their strength. Unfortunately due to the recent events in our neighborhood (NYC) we haven't had a chance to experiment much more lately.
Oh and its more like liquid than goo, so dont get your hopes of creating a giant black goo monster up too high.
Anyway, if you want to pick some up for yourself try these places:
Edmund Scientific
(also has magnets, electromagnets)
Teacher Source
(this is where we got our large 1000ml bottle)
and more listed at the official ferroftec web site:
ferrofluidics
-nA
^nA! Creatures in my Head
i want one!! i've only been able to access a couple sites, considering everything's been slashdotted :P but this looks fun !!
friend walks in.. "so.. what did you do today?"
me: ..well.. i went to school, took care of my son.. and played with Ferrofluids !@#$#@
friend calmy (but nervously) walks away..
Liquid mercury isn't affected by magnets.
-- MarkusQ
this stuff's been in science education supply houses for some time. it's very cool, and you can approximate it with very ancient drained engine oil - iron block of course - and of course if your jalopy yeilds much of this stuff, you're going to have another challenge on your hands soon enough, an old junkyard with otherwise shot engines are a good source.
remember, used engine oil is not very pleasant stuff...
to visualize field lines, larger iron particles in mineral oil in a clear plastic vial is cool too.
edmunds, fisher sci, carolina have these.
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Small Parts has an experement kit with 50cc bottle and some megnents to play with. Look at at the left bar and go down, it's under "DEMO KITS". I ordered one a while ago, it's pretty neet. ($50.00)
http://www.wondermagnets.com some of their big honkin ones put a hurt on you if you get in their way.
This has been around >15 years. In fact some of the tools that made the chips in your PC probably had ferrofluidic bearings. Because these liquids can be held in place by magnets, you can make a feedthrough into a vaccum chamber that can be rotated. The fluids have low vapor pressure so you can have a high vacuum system with a rotating shaft entering it - that's very difficult normally. The fluid seals between the shaft and the sleeve, where the air would normally leak in. Good down to about 10^-10 of an atmosphere. Try www.ferrofluidics.com .
Regards, John the semiconductor capital equipment designer.
This could provide for some fun situations. For example, say you're at a bar and you "accidentally" spill your magnetic beer all over a cute girl's shirt. Now say, hypothetically that you just happened to have one of those magic wand magnets in your pocket. I'm just saying. It could be entertaining.
---------
Sometimes there's no other way to win, except by falling.
and my Immortality rings I, Alex Chiu, will not simply live forever, but I will become a true god and live even further than existence itself!
Why a simple enema of these special magnetic fluids will allow me to shed the frailties of man and become a living, breathing force of pure magnetic power! Wounds will be instantly healed as my cells will become perfectly aligned into position in a show of magnetic healing force! I will never age since my cells will also stay in perfect order and never fail! You will all eventually bow down before me!
Muhahahahaha!!!
Oh and if you Slashdotters need neodymium magnets, my rings are made of them. Go ahead and buy some.
They're very good magnets. Go get them.
Please?
Please??
I'm hungry and I can't get a job since I tend to destroy monitors by walking near them.
-Fantastic Lad
I wonder if you could come up with a non-toxic ferrofluid, sneak it in someone's drink, then pull them around with a big huge magnet? Or even better... he's sure got an attractive personality
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That link steers you to his website, not cool if you ask me. You can right click and save http://dhcp-128-194-69-244.resnet.tamu.edu/ferrofl uid.mpeg
It reminds me of that "water" on the islands of Riven that would avoid heat. It would travel up the sides of glass, and even suspend itself in air if given sufficient heat to avoid. Neat stuff!
interesting site about magnetism, FOund Here
Your hair look like poop, Bob! - Wanker.
Don't the editors read Slashdot?!
2 50 &mode=thread
2 28 &mode=thread
Moldable Magnets
http://slashdot.org/article.pl?sid=00/02/25/087
Magnetic Fluid Art
http://slashdot.org/article.pl?sid=01/08/22/036
and more, searching for "fluid magnets" on Slashdot.
It cant form complex objects, but it can form basic weapons, sharp objects and stabbing weapons.
The Terminator
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So when do we get to see them build the first Liquid Terminator out of this stuff?
I realize the first metal Terminator has yet to be done, but after Sony realizes that AIBO isn't very useful, I think we'll start seeing some really fun stuff walking out of their labs.
The whole Liquid Metal Morphing Killer Robot thing though, man... that's where it's at!
I can't wait until I have a barrels full of minions to call upon for my evil deeds!
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I recall reading about magnetorheological fluids about 4-5 years ago in one of those "homebrew VR" books. They wanted to try using them as force-feedback devices (e.g. fluid under the fingers in a glove which hardens to suggest a solid surface). Basically iron filings in oil, as I can remember. They also talked about electrorheological fluids (sp?)- basically cornstarch suspended in vegetable oil- a little easier to control than MR fluid in that you didn't need cumbersome electromagnets, just a small step-up circuit needed for the roughly 25 Kvolts to get the lattice to "lock" (i.e. to get the ER fluid to harden). (Despite what you're thinking, it wasn't dangerous if everything was tight and well-insulated). They quoted a company's price for commercial ER fluid- something like $200/quart- when the homebrewer could do just as well with cornstarch/oil. I'd think you'd need to put an emulsifier in there if you were to hold the cornstarch particles in suspension for any extended period of time. Now I want to find that darn book... believe it was "Garage Virtual Reality" by Linda Jacobson. Might've been the other half-dozen "homebrew VR" books I bought around that time, though. :-)
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MR fluids are great for many applications. Last year I worked on a project in which a professor and I developed seismic structural dampers using MR fluids. Durring and earthquake, the ammount of damping a building should have is dependant on the velocity and acceleration of the ground under the structure. Using MR fluids, the damper can have an extremely wide range of forcees, and thus can stiffen and unstiffen the building as needed.
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AC: Don't use that phrase that way unless you want to look like an idiot.
While I don't particularly mind looking like an idiot, I doubt that my use of "begs the question" here will do it.
To "beg the question" is to speak as if you are addressing a point, when in fact you are not. The original poster suggested having someone drink magnetic liquid and then going after them with a magnet. We all know what the expected outcome was. Then I suggested sending them to the airport, as if I knew what the outcome would be (and was making a sly joke), when in fact I don't know what would happen. Thus I was begging the question.
What may seem odd here is that I didn't wait for someone else to point this out; I called myself on it. While this is about as common as someone saying "I'm full of shit here,..." or "If you'd like to hear a bogus view, I think..." that doesn't make it wrong.
-- MarkusQ
Ferrofluid is fun stuff, and has all kinds of uses as others have outlined...including mechanical parts, seals, and rocket fuel.
My employer also uses ferrofluids for cell separations for diagnostic purposes.
Currently, we're developing an early stage cancer diagnostic system with the ferrofluid-based technology.