Magnetorheological fluid - nine syllables for "Huh"?

July 26, 2014 11:37 AM

A magnetorheological (MR) fluid is a fluid that changes the way it flows in the presence of a magnetic field.

A typical MR fluid is made of very small solid particles that are suspended in a liquid and attracted to a magnet. It might be cushioning your car or bus.

You can make your own MR fluid by following the steps listed here or you can just watch and wonder here

The wiki of course has an explanation. One and further.

There is some overlap in this post and a post ten years previous from the always excellent Specklet.

posted by vapidave (19 comments total)

Fucking magnets. How do they work?
posted by maxsparber at 11:42 AM on July 26, 2014 [2 favorites]

Good question. We should talk to a scientist!
posted by etc. at 12:14 PM on July 26, 2014 [2 favorites]

caution: do not eat
posted by leotrotsky at 12:25 PM on July 26, 2014

This got me an A on my science fair project back in 1995. Ripped it straight out of an issue of Scientific American.
posted by PenDevil at 12:29 PM on July 26, 2014 [1 favorite]

tiny blobby shai hulud, may his passage cleanse the world.
posted by SharkParty at 12:47 PM on July 26, 2014 [1 favorite]

If you play the gif in that first link backwards, it's NSFW.
posted by glhaynes at 1:11 PM on July 26, 2014

"it creeps
And leaps and glides and slides
Across the floor
Right through the door
And all around the wall"
posted by IndigoJones at 1:31 PM on July 26, 2014

Wonder how hard it would be to make a bicycle seat post damper out of this stuff, a spring and some permanent magnets.

From the car or bus link:

For the future, automotive manufacturers plan to expand the magnetorheological fluid for the development of fluid based clutch systems, to be used on push-button 4WD vehicles. Unlike the suspension systems, which use electricity for the creation of a magnetic field, the clutches will use electromagnets to solidify the fluid.

Did he mean to say 'the clutches will use permanent magnets to solidify the fluid'?
posted by jamjam at 1:35 PM on July 26, 2014 [1 favorite]

Amusingly, my first thought/quip when I saw this post was, "So...rusty water, then?" (guessing that it could be suspended iron filings). Sure enough, from the "steps listed here" link:

It’s also possible to make iron filings very small and to suspend them in a liquid.

Incidentally, many years ago I used to dance under the name Rusty Waters.
posted by Greg_Ace at 2:01 PM on July 26, 2014

Wonder how hard it would be to make a bicycle seat post damper out of this stuff, a spring and some permanent magnets.

I don't know how hard it would be, but do know that it would be needlessly expensive, so expect to see your dentist or accountant adding one to their carbon-fiber-everything road bike soon.
posted by indubitable at 2:43 PM on July 26, 2014

A disembodied sphincter traveling backwards in time un-excreting everything in its path. Not entirely unlike Stephen King's Langoliers.
posted by Hairy Lobster at 3:12 PM on July 26, 2014

These systems require electronic sensors and electromagnets to work. I doubt they will find their way onto bicycles anytime soon.
posted by humanfont at 3:15 PM on July 26, 2014 [1 favorite]

It might be cushioning your car or bus.

Or your drillstring (skip to 2:45 ...)
posted by ZenMasterThis at 3:33 PM on July 26, 2014

Did he mean to say 'the clutches will use permanent magnets to solidify the fluid'?

I doubt it, you frequently want to be able to de-couple parts of the drivetrain with 4wd vehicles. Think switching from two to four wheel drive. Or even switching from an open to a locked differential. The electromagnet would allow you to do this on demand.
posted by inparticularity at 3:54 PM on July 26, 2014

If you play the gif in that first link backwards, it's NSFW.

If you play it forward, you will hear me yelling "What?" and making a strangled screaming sound based on a sample of n=1 occurrences.
posted by psoas at 4:05 PM on July 26, 2014

I don't know why, but stuff like this and the ferromagnetic fluid videos really squick me out.
posted by slogger at 6:42 PM on July 26, 2014

I always wondered how it will look when the self-replicating nanobots consume us and everything else on earth.
posted by double block and bleed at 7:59 PM on July 26, 2014

I've worked on a couple MR dampers for large off road vehicles. The fluid is actually denser than aluminum. The bump course comparison videos we had are amazing. It's a huge difference. Especially on a 20 ton vehicle.
posted by TheJoven at 8:09 PM on July 26, 2014 [1 favorite]

NEEDS GOOGLY EYES
posted by JHarris at 11:03 PM on July 26, 2014 [1 favorite]