Ferrofluid

A colloidal suspension of Fe₃O₄ nanoparticles acts as a magnetic "liquid" and forms amazing spikes when a magnet is brought close. The particles act as small compasses marking the magnetic field lines of the magnet.

The ferrofluid you see consists of magnetic nanoparticles suspended in water. As a magnet is brought up to the ferrofluid, spikes form in the fluid and can dance in response to movements of the magnet.

2001