33 ms·

I wonder why that is. Given that the container is sealed properly, and they use electronics with magnets, I just don't see any part that is subject to such mass

by Kenji 11y ago

I wonder why that is. Given that the container is sealed properly, and they use electronics with magnets, I just don't see any part that is subject to such massive wear. EDIT: Thanks, jpatokal, that cleared things up.

jpatokal 11y ago
Ferrofluids are fundamentally unstable. They're colloidal suspensions that rely on surfactants to keep the particles apart, and as the surfactants degrade, the particles start clumping together and falling out of suspension. https://en.wikipedia.org/wiki/Ferrofluid#Description https://en.wikipedia.org/wiki/Ferrofluid#Description As a practical demonstration of this, there's an ancient ferrofluid exhibit (80's?) at a local science museum. While the fluid itself kinda-sorta "works" in that you get the pretty spiky shapes when zapped with an electromagnet, the edges and bottom of the glass case are thickly coated in viscous black gunk.
tomwphillips 11y ago
Ferrofluids are magnetic nanoparticles, usually iron oxide, with small molecules called surfactants stuck to their surface. These stop the nanoparticles aggregating. Eventually the surfactants themselves will come off, causing aggregation. Lumps of iron oxide precipitate out of the liquid and sink to the bottom. No doubt better surfactants will be developed that take a very long time to degrade.
- daveloyall 11y ago
  Could you confirm or deny that you are using the word "nanoparticles" carefully? I think that the ferrous particles in ferrofluids are mere particles. They'd have to be very, very small to be classified as nano, and we've seen before that making particles of an ordinary material that small can change its properties, ala "transparent titanium dioxide".
  - chris_va 11y ago
    "Ferrofluids are composed of nanoscale particles (diameter usually 10 nanometers or less) of magnetite, hematite or some other compound containing iron." - Wikipedia
- bro-stick 11y ago
  Makes one wonder about the usable lifetime of such an art piece.
  - stephengillie 11y ago
    Indeed, a piece designed to degrade within a few months seems like an art trope.

by Kenji 11y ago

jpatokal 11y ago

Ferrofluids are fundamentally unstable. They're colloidal suspensions that rely on surfactants to keep the particles apart, and as the surfactants degrade, the particles start clumping together and falling out of suspension. https://en.wikipedia.org/wiki/Ferrofluid#Description https://en.wikipedia.org/wiki/Ferrofluid#Description As a practical demonstration of this, there's an ancient ferrofluid exhibit (80's?) at a local science museum. While the fluid itself kinda-sorta "works" in that you get the pretty spiky shapes when zapped with an electromagnet, the edges and bottom of the glass case are thickly coated in viscous black gunk.

tomwphillips 11y ago

Ferrofluids are magnetic nanoparticles, usually iron oxide, with small molecules called surfactants stuck to their surface. These stop the nanoparticles aggregating. Eventually the surfactants themselves will come off, causing aggregation. Lumps of iron oxide precipitate out of the liquid and sink to the bottom. No doubt better surfactants will be developed that take a very long time to degrade.

daveloyall 11y ago
Could you confirm or deny that you are using the word "nanoparticles" carefully? I think that the ferrous particles in ferrofluids are mere particles. They'd have to be very, very small to be classified as nano, and we've seen before that making particles of an ordinary material that small can change its properties, ala "transparent titanium dioxide".
- chris_va 11y ago
  "Ferrofluids are composed of nanoscale particles (diameter usually 10 nanometers or less) of magnetite, hematite or some other compound containing iron." - Wikipedia
bro-stick 11y ago
Makes one wonder about the usable lifetime of such an art piece.
- stephengillie 11y ago
  Indeed, a piece designed to degrade within a few months seems like an art trope.