Ferrofluid

A ferrofluid is a liquid that becomes strongly magnetized in the presence of a magnet. The fluid consists of nanoscale particles made out of iron based compounds. The particles are suspended evenly throughout a carrier fluid, allowing them to affect the overall magnetic reaction. If you place the ferrofluid by any kind of magnetic field, little “needles” will appear. This is because the iron based particles magnetize when you place them in a magnetic field. The stronger the field is, the larger and wider the “spikes” get. (Click the link to learn how to make ferrofluid)
http://www.popsci.com/diy/article/2009-09/making-ferrofluids-work-you

Ferrofluid


A ferrofluid is a liquid that becomes strongly magnetized in the presence of a magnet. The fluid consists of nanoscale particles made out of iron based compounds. The particles are suspended evenly throughout a carrier fluid, allowing them to affect the overall magnetic reaction. If you place the ferrofluid by any kind of magnetic field, little “needles” will appear. This is because the iron based particles magnetize when you place them in a magnetic field. The stronger the field is, the larger and wider the “spikes” get. (Click the link to learn how to make ferrofluid)

http://www.popsci.com/diy/article/2009-09/making-ferrofluids-work-you