Every once in a while, we all need a good reminder that electromagnetism is mind-boggling. Thankfully, in its latest video, the YouTube channel The Action Lab offers a stellar nod to the force of nature by showcasing a spinning magnet in a blob of ferrofluid. Which itself levitates above a frigid superconductor.
The Action Lab, a channel that loves “performing exciting experiments,” recently posted the above video. The channel’s owner and host, James J. Orgill, says in the video’s description he performed the experiment to show people what happens when you bring a superconductor near ferrofluid. Which itself is inside of another magnetic field.
To perform the experiment, Orgill sets up a superconductor—likely a metal alloy—that is ultra-cold thanks to liquid nitrogen. (A superconductor is a material that can conduct electricity without producing any resistance.) The Action Lab host then places a magnet above the superconductor so it both floats and spins in place.
The Action Lab
Once he’s placed the magnet, Orgill proceeds to pour ferrofluid all over the floating, spinning magnet; resulting in what ultimately looks like a jumbo, pill-shaped globe of black oil levitating above the superconductor.
Regarding the physics at play, in essence, the superconductor captures the magnet with its own electromagnetic field. When Orgill pours the ferrofluid— a liquid consisting of iron-oxide particles, a carrier fluid (like water), and a surfactant that binds the two together—over the floating magnet, magnetic attraction holds it in place. The magnet, simultaneously, is able to levitate and roll continuously above the superconductor; something it can do thanks to the latter’s lack of electrical resistance.
The Action Lab
As for the second half of the video, Orgill focuses on what happens when you combine ferrofluid and a huge neodymium magnet. And while the results are, likewise, surreal, it’s clear Orgill probably just needed to use up his stash of the liquid. But who cares? It’s another experiment that helps us all to remember there are electromagnetic fields everywhere. And that they’re interacting strangely all the time.