The amazing ferrofluid is a truly magnetic liquid that consists of micron size magnetic particles (magnetite) in a mineral oil. Particles are coated in a surfactant which prevents them clumping together.When a magnet is in close proximity the magnetic particles in the Ferrofluid take up the shape of the magnetic field to create a 3-D version of the classic iron fillings on a piece of paper experiment.The apparent density of ferrofluid can be changed by applying a magnetic field. E.g., place a one pence piece in a shallow dish (5mm) of ferrofluid and it will sink. Bring a powerful magnet underneath and the coin will float!Supplied in a plastic jar containing 10ml of Ferrofluid. A rare earth magnet is also supplied.