Partially molten systems, in which a change of phase between liquid and solid can occur, arise in a wide variety of settings, such as in the solidification of magma chambers and the Earth's core and in the casting of metallic alloys. These multi-phase systems are often physically complex and exhibit anomalous behavior not seen in single phase systems. The study of such systems has bee hampered by the lack of a set of governing equations derived from first principles. This research will be a systematic attempt to derive such equations and to elucidate some of their unusual properties. Also the characteristics of the mushy zone which forms as an aqueous solution of ammonium chloride is cooled from below will be studied experimentally to determine whether the theory can successfully predict the occurrence and characteristics of the chimneys or channels which from spontaneously.
