Ferrofluid
Updated: 05/14/2017 by Computer Hope
A ferrofluid is a liquid that becomes highly magnetized when it is near a magnetic field. It consists of tiny magnetic particles suspended in water or an organic solvent. Each of the magnetic particles is coated with a special compound that keeps it from clumping with other particles once they become magnetized.
Ferrofluids were invented in 1963 by Steve Papell at NASA as a liquid rocket fuel that could be pumped in a zero gravity environment.