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.

Comments

SIGGRAPH

[LS]

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

Ferrofluid links

[Black Acid]

Ferrofluids are indeed cool but DansData is not the only place which has information on them. They can be used to create nanostructures and defy gravity for environmental engineering. In case you're wondering what exactly ferrofluids are, here's a good excerpt from the previous link:

Ferrofluids are colloidal suspensions of nanoscale magnetic particles in a carrier fluid; the particles form magnetic domains separated by coats of dispersant only a molecule thick. These magnetic fluids have been used in many ways--to form airtight seals around rapidly moving parts, to move drugs in the bloodstream and rocket propellants in spacecraft, even to cool and dampen powerful audio speakers. Now steerable ferrofluids may give rise to new tools for subsurface environmental engineering and laboratory safety.

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.

Ferrofluids

[smunt]

check this link. It's the first link on the page (which is unreachable by now).

Some other links:

[morcheeba]

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.

Never played with magnetic fluid???

[Mike McTernan]

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)

Again, Spherical Magnets

[FFFish]

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.

not that cool really

[Anonymous Coward]

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.

Mirror for the video

[Skaven04]

I got the video downloaded just in time...

here

fairly good mirror

[Anonymous Coward]

http://homepage.mac.com/crayz/magnets/magnets.htm

Thank Apple for the bandwidth

Re:how long will it take

[camusflage]

We won't see any infomercials for this stuff. Toxic, flammable, corrosive and mutagenic are just a few of the drawbacks. Add to it that the resultant fluid will "permanently stain almost any fabric".

Where to score some black magnetic goo.

[napa1m]

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

get ferrofluid here

[AnotherBrian]

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)

Has been around years but is still cool

[johndr]

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.

Direct link, ahem ahem

[Anonymous Coward]

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