Ferrofluid Magnetic Display — Physics of Field Lines in a Vial

Maxwell's equations made visible — on your desk.

The ferrofluid responds to magnetic field lines, forming spike structures (Rosensweig instability) when a neodymium magnet is brought close. The spikes align with the local field gradient — the geometry you see is a direct physical map of the magnetic field topology. Iron nanoparticles suspended in oil, each coated to prevent agglomeration; the carrier fluid magnetizes as a bulk material. The spike height and spacing are determined by a competition between magnetic energy, surface tension, and gravity — a solvable problem in continuum mechanics.

Bring a magnet near the vial and watch the topology change in real time. Rotate the magnet and the spikes rearrange. Each configuration is a different solution to the same field equation.

• 10ml ferrofluid in sealed borosilicate vial
• 3 neodymium disc magnets
• Acrylic display stand
• 6 demonstration instructions

Ships within 7–14 business days.