Andrzej Danel of the University of Agriculture in Krakow produced these spiky structures by placing a strong magnet under a 5 cm wide puddle of a ferrofluid. This ink black fluid consists of nanosized particles of iron and iron oxides floating inside a carrier solvent with a significant portion of a surfactant, like an oil. Molecules of the surfactant surround the iron-containing particles and keep the particles from clumping up into a solid mound as they get magnetized. The particles can move around in the solvent in response to the magnetic field, resulting in the 3-D structures like these spikes. Danel and his colleagues use this ferrofluid demo and others to spark children’s interest in science.
Submitted by Andrzej Danel
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