A ferrofluid is a liquid containing thousands of nanoscale ferromagnetic particles (tiny metal spheres) which become strongly magnetised in the presence of a magnetic field. These particles are coated with a ‘surfactant’ which prevents them from all clumping together when a magnetic field is applied. This allows them to move freely past each other and align themselves in the direction of the magnetic field lines with minimal amounts of friction. You can find them inside high-end speakers and also in some CD/DVD lasers.
‘This is all well and good, but what does it all this mean?!’ I hear you asking. Well the upshot of all this is that because the particles are so small and because there is so little friction between them, they behave exactly as if they were a liquid. This allows you to use normal household magnets to sculpt them into otherworldly shapes and designs like the ones shown below.
They can also be suspended in water to allow even more coolness to ensue, much like in this new Kickstarter project which is definitely not where I got the idea for this post…
If you feel like having a go yourself, then you can pick some ferrofluid up along with some helpful supplies from scuddlebutt3 (best deal I could find in UK). I’ve ordered myself some to have a play with and I’ll be sure to post what I get up to!