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thorium
(Encyclopedia)thorium thôrˈēəm [key] [from Thor], radioactive chemical element; symbol Th; at. no. 90; mass number of most stable isotope 232; m.p. about 1,750℃; b.p. about 4,790℃; sp. gr. 11.7 at 20℃; va...cerium
(Encyclopedia)cerium sērˈēəm [key] [from the asteroid Ceres], metallic chemical element; symbol Ce; at. no. 58; at. wt. 140.116; m.p. 799℃; b.p. 3,426℃; sp. gr. 6.77 at 25℃; valence +3 or +4. Cerium is a ...serpentine
(Encyclopedia)serpentine sûrˈpəntēn, –tīn [key], hydrous silicate of magnesium. It occurs in crystalline form only as a pseudomorph having the form of some other mineral and is generally found in the form of...gills, in biology
(Encyclopedia) CE5 Gills of a fish: Side view (A) and ventral view (B) gills, external respiratory organs of most aquatic animals. In fishes the gills are located in gill chambers at the rear of the mouth (phary...cuttlefish
(Encyclopedia)cuttlefish, common name applied to cephalopod mollusks that have 10 tentacles, or arms, 8 of which have muscular suction cups on their inner surface and 2 that are longer and can shoot out for graspin...cephalopod
(Encyclopedia) CE5 Internal anatomy of a squid, Loligo, representative mollusk of the class Cephalopoda cephalopod sĕfˈələpŏdˌ [key], member of the class Cephalopoda, the most highly organized group of mol...Phidias
(Encyclopedia)Phidias or Pheidias both: fĭdˈēəs [key], c.500–c.432 b.c., Greek sculptor, one of the greatest sculptors of ancient Greece. No original in existence can be attributed to him with certainty, alth...seismology
(Encyclopedia)seismology sīzmŏlˈəjē, sīs– [key], scientific study of earthquakes and related phenomena, including the propagation of waves and shocks on or within the earth by natural or artificially genera...Vesta, in astronomy
(Encyclopedia)Vesta vĕsˈtə [key], in astronomy, the fourth asteroid to be discovered. It was found in 1807 by H. Olbers. It is the third largest asteroid in size, with a diameter of c.326 mi (525 km). Its averag...Browse by Subject
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