Columbia Encyclopedia

Search results

228 results found

silicate

(Encyclopedia)silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may b...

cobalt, chemical element

(Encyclopedia)cobalt, metallic chemical element; symbol Co; at. no. 27; at. wt. 58.9332; m.p. 1,495℃; b.p. about 2,870℃; sp. gr. 8.9 at 20℃; valence +2 or +3. Cobalt is a silver-white, lustrous, hard, brittle...

rainbow

(Encyclopedia)rainbow, arc showing the colors of the spectrum, violet inside and red outside, which appears when the sun shines through water droplets. It often appears while the sun is shining after a brief thunde...

science fiction

(Encyclopedia)science fiction, literary genre in which a background of science or pseudoscience is an integral part of the story. Although science fiction is a form of fantastic literature, many of the events recou...

shark

(Encyclopedia)shark, member of a group of almost exclusively marine and predaceous fishes. There are about 250 species of sharks, ranging from the 2-ft (60-cm) pygmy shark to 50-ft (15-m) giants. They are found in ...

Tehran

(Encyclopedia)Tehran or Teheran both: tāˌəränˈ, –rănˈ [key], city (1991 pop. 6,475,527), capital of Iran and Tehran prov., N Iran, near Mt. Damavand. It is Iran's largest city and its administrative, comme...

gospel music

(Encyclopedia)gospel music, American religious musical form that owes much of its origin to the Christian conversion of West Africans enslaved in the American South. Gospel music partly evolved from the songs slave...

brown dwarf

(Encyclopedia)brown dwarf, in astronomy, celestial body that is larger than a planet but does not have sufficient mass to convert hydrogen into helium via nuclear fusion as stars do. Also called “failed stars,”...

molybdenum

(Encyclopedia)molybdenum məlĭbˈdənəm [key] [Gr.,=leadlike], metallic chemical element; symbol Mo; at. no. 42; at. wt. 95.96; m.p. about 2,617℃; b.p. about 4,612℃; sp. gr. 10.22 at 20℃; valence +2, +3, +4...

zinc

(Encyclopedia)zinc, metallic chemical element; symbol Zn; at. no. 30; at. wt. 65.38; m.p. 419.58℃; b.p. 907℃; sp. gr. 7.133 at 25℃; valence +2. Zinc is a lustrous bluish-white metal. It is found in Group 12 o...