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bead test

(Encyclopedia)bead test, test used in the identification of certain metals. Some metallic ions that cannot be identified by a flame test are identified by a bead test. The test can also be used to confirm the resul...

ignition

(Encyclopedia)CE5 Ignition system ignition, apparatus for igniting a combustible mixture. The German engineer Nikolaus A. Otto, in his first gas engine, used flame ignition; another method was heating a metal t...

crow, in zoology

(Encyclopedia)crow, partially migratory black bird, genus Corvus, of the same family as the raven, the magpie, the jay, and the rook and the jackdaw of Europe. The American, or common, crow, C. brachyrhynchos, abou...

hydroponics

(Encyclopedia)hydroponics, growing of plants without soil in water to which nutrients have been added. Hydroponics has been used for over a century as a research technique, but not until 1929 were experiments condu...

Cronkite, Walter

(Encyclopedia)Cronkite, Walter (Walter Leland Cronkite, Jr.) krŏngˈkīt, krŏnˈ– [key], 1916–2009, American news broadcaster, b. St. Joseph, Mo. He left (1935) the Univ. of Texas to write for the Houston Pre...

wind tunnel

(Encyclopedia)wind tunnel, apparatus for studying the interaction between a solid body and an airstream. A wind tunnel simulates the conditions of an aircraft in flight by causing a high-speed stream of air to flow...

spark chamber

(Encyclopedia)spark chamber, in physics, device for recording the passage of elementary particles produced by reactions in a particle accelerator. Particles pass through a stack of metal plates or wire grids that a...

aluminum

(Encyclopedia)aluminum ălˌyo͞omĭnˈēəm [key], metallic chemical element; symbol Al; at. no. 13; at. wt. 26.98154; m.p. 660.37℃; b.p. 2,467℃; sp. gr. 2.6989 at 20℃; valence +3. Aluminum is a silver-white...

electric circuit

(Encyclopedia)CE5 A. Series circuit: Current is the same through each resistance; voltage divides in direct proportion to each resistance. B. Parallel circuit: Voltage drop is the same over each resistance; curr...

Hersh, Seymour Myron

(Encyclopedia)Hersh, Seymour Myron, 1937–, American investigative journalist, b. Chicago, grad. Univ. of Chicago (1958). He began his career (1959) at a local news bureau, then became a wire service correspondent...