Preparing the Ferrofluid

1.) After preparing the Fe₃O₄ mixture using the buret, obtain a magnet and transfer the mixture to a weighboat.

2.) Hold the magnet underneath the weighboat so that the magnetic black sludge is fixed to the bottom and pour off the supernatant solution.

3.) Rinse off the ferrofluid with DI H₂O then pour out the supernatant as before. Repeat this several times.

4.) Add the surfactant then work the ferrofluid using both a stirrer and the magnet underneath. This may take several minutes.

5.) Eventually, small spikes will emerge from the ferrofluid when the magnet is nearby. These spikes follow the magnetic field lines of the magnet and are countered by surface tension forces.