When ferrofluid is brought near a spherical magnet, spikes form as the magnetite in the liquid aligns with the field lines.
If you liked this video, check these ones out:
Possible Incorporated Topics:
Ferrofluid is a man-made substance that acts like a liquid magnet. It is composed of tiny particles of magnitite (about 10 nm in diameter). These particles are suspended in a soap-like surfactant that keeps them separated. They are then free to flow around and do fascinating things like form spikes along magnetic fields. This is why as the magnet moves farther away, and the magnetic field lines get further apart, the spikes spread out.
Note: Also, do NOT let the magnet and the ferrofluid come into direct contact, as it is very difficult to get off, and will make a huge mess. Make sure you have lots of paper towels on hand for any spills as ferrofluid stains easily. Gloves are recommended.