We combine small angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS) with aerodynamic levitation techniques to study in situ phase transitions in the liquid state under contactless conditions. At very high temperatures yttria-alumina melts show a first order transition, previously inferred from phase separation in quenched glasses. We show how the transition coincides with a narrow and reversible maximum in SAXS indicative of liquid unmixing on the nanoscale combined with an

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... upt realignment in WAXS features related to reversible shifts in polyhedral packing on the atomic scale. We also observed a rotary action in the suspended supercooled drop driven by repetitive transitions -a polyamorphic rotor -from which the reversible changes in molar volume (1.2+/-0.2cm 3 ) and entropy (19+/-4 J/mol/K) can be estimated.