ferrofluids in action

[Jon]

Thanks PJs for the tip on ferromagnetic fluids; fascinating stuff, hope to have more on it in the future.

Ferrofluids are fluids that can be controlled with a magnetic field; essentially composed of magnetic nanoparticles that are dispersed in a liquid. Invented in 1963 by a NASA scientist Steve Papell, as a fuel that could be drawn to a pump in zero gravity.



Applications are promising, but limited. Liquid seals seem to be the most common, but ferrofluids can also be used for friction reduction, propulsion, medical drug targeting, and optics.

Stirling motor builders have used them to seal pistons:

People are DIYing them from vegetable oil and printer toner.

Of course life would not be complete without a Kickstarter for a ferrofluid lava lamp, uh, I mean "motion lamp of the future". I thought this one was a parody, but it's actually a real, successfully funded Kickstarter: