Drops of oil in Mn(SO4)(aq) and drops of the solution in oil show opposite effects when brought near a rare earth magnet. Oxygen, nitrogen, and air bubbles atop water show expected attraction, repulsion, and null behavior, respectively. Air bubbles atop aqueous Mn(SO4) show paradoxical behavior because the magnet's attraction of the solution forms a complex crest. The existence and shape of this crest is examined, and the unexpected behavior used to motivate student examination of paramagnetism. Several improvements in the bubble demonstration are suggested. A rare earth magnet is also powerful enough to demonstrate paramagnetism in crystals of Fe2(SO4)3·9H2O, FeSO4·7H2O, CoCl2·6H2O, MnSO4·H2O, and to a lesser extent CuSO4·5H2O, CuCl2·2H2O, NiCl2·6H2O, MnO2, and NiSO4·7H2O.
More Information
Citation
Sauls, Frederick C.; Vitz, Ed. J. Chem. Educ.2008, 85, 529.
Keywords
Demonstrations; First-Year Undergraduate / General; High School / Introductory Chemistry; Inorganic Chemistry; Magnetic Properties; Misconceptions / Discrepant Events
History
Created:
Last Updated:
2/26/2008
2/29/2008
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