repeated crystallization
21Weathering — This article is about weathering of rocks and minerals. For weathering of polymers, see Polymer degradation and Weather testing of polymers. Weathering is the breaking down of rocks, soils and minerals as well as artificial materials through… …
22Ceramic engineering — Simulation of the outside of the Space Shuttle as it heats up to over 1,500 °C (2,730 °F) during re entry into the Earth s atmosphere Ceramic engineering is the science and technology of creating objects from inorganic, non metallic… …
23volcano — /vol kay noh/, n., pl. volcanoes, volcanos. 1. a vent in the earth s crust through which lava, steam, ashes, etc., are expelled, either continuously or at irregular intervals. 2. a mountain or hill, usually having a cuplike crater at the summit,… …
24separation and purification — ▪ chemistry Introduction in chemistry, separation of a substance into its components and the removal of impurities. There are a large number of important applications in fields such as medicine and manufacturing. General principles… …
25Crystal — Crystals redirects here. For other uses, see Crystals (disambiguation). This article is about crystalline solids. For the type of glass, see lead crystal. For other uses, see Crystal (disambiguation). Quartz crystal. The individual grains of this …
26Recrystallization — (see also crystallization) is a physical process that has meanings in chemistry, metallurgy and geology.ChemistryIn chemistry, recrystallization is a procedure for purifying compounds. The most typical situation is that a desired compound A is… …
27MUSIC — This article is arranged according to the following outline: introduction written sources of direct and circumstantial evidence the material relics and iconography notated sources oral tradition archives and important collections of jewish music… …
28White dwarf — For other uses, see White dwarf (disambiguation). Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint pinprick of light to the lower left of the much brighter Sirius A …
29Mollusc shell — Closed and open shells of a marine bivalve, Petricola pholadiformis. A bivalve shell is composed of two hinged valves which are joined by a ligament …
30Witch trials in the Early Modern period — Punishments for witchcraft in 16th century Germany. Woodcut from Tengler s Laienspiegel, Mainz, 1508. The Witch trials in the Early Modern period were a period of witch hunts between the fifteenth and eighteenth centuries,[1] when across Early… …
