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laser

(Encyclopedia)CE5 Ordinary light sources produce incoherent light, while a laser produces a beam of coherent light. laser [acronym for light amplification by stimulated emission of radiation], device for the cr...

carbon

(Encyclopedia)CE5 The three solid forms of pure carbon: In the diamond crystal each carbon atom is surrounded symmetrically by four other carbons (at each of the four corners of a tetrahedron). In the graphite c...

World Trade Center

(Encyclopedia)World Trade Center, former building complex in lower Manhattan, New York City, consisting of seven buildings and a shopping concourse on a 16-acre (6.5-hectare) site; it was destroyed by a terrorist a...

Kentucky, state, United States

(Encyclopedia)CE5 Kentucky kəntŭkˈē, kĭn– [key], state of the SE central United States. It is bordered by West Virginia and Virginia (E); Tennessee (S); the Mississippi River, across which lies Missouri (...

Utah , state, United States

(Encyclopedia)CE5 Utah yo͞oˈtäˌ [key], Rocky Mt. state of the W United States. It is bordered by Idaho and Wyoming (N), Colorado (E), Arizona (S), and Nevada (W), and touches New Mexico in the SE, at the Fou...

Wisconsin, state, United States

(Encyclopedia)CE5 Wisconsin wĭskŏnˈsən, –sĭn [key], upper midwestern state of the United States. It is bounded by Lake Superior and the Upper Peninsula of Michigan, from which it is divided in part by the...

African art

(Encyclopedia)African art, art created by the peoples south of the Sahara. The predominant art forms are masks and figures, which were generally used in religious ceremonies. The decorative arts, especially in text...

human evolution

(Encyclopedia)human evolution, theory of the origins of the human species, Homo sapiens. Modern understanding of human origins is derived largely from the findings of paleontology, anthropology, and genetics, and i...

rock music

(Encyclopedia)rock music, type of music originating in the United States in the mid-1950s and increasingly popular throughout much of the world. A turning point in rock music occurred in the mid-1970s in the ...

Nevada

(Encyclopedia)CE5 Nevada nəvădˈə, –vä– [key], far western state of the United States. It is bordered by Utah (E), Arizona (SE), California (SW, W), and Oregon and Idaho (N). In the 20th cent. the ...