Ed Leedskalnin's Magnetic Current. Illustrations and Research.
When placed in a magnetic field this fluid takes on the shape of the field passing through it. Ferrofluids allow us to see the lines of force in 3D , study interactions of magnetic fields and create magnetic art!
have a look at how the peaks dance around. It would be a very interesting experiment to see how the fluid would react if placed over a wire carrying an electrical current.