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zinc oxide

(Encyclopedia)zinc oxide, chemical compound, ZnO, that is nearly insoluble in water but soluble in acids or alkalies. It occurs as white hexagonal crystals or a white powder commonly known as zinc white. Zinc white...

Stark, Johannes

(Encyclopedia)Stark, Johannes, 1874–1957, German physicist, Ph.D. Univ. of Munich, 1897. From 1900 until he retired in 1922, Stark served short stints on the faculties of several academic institutions, including ...

Le Châtelier's principle

(Encyclopedia)Le Châtelier's principle, chemical principle that states that if a system in equilibrium is disturbed by changes in determining factors, such as temperature, pressure, and concentration of components...

bubble chamber

(Encyclopedia)bubble chamber, device for detecting charged particles and other radiation by means of tracks of bubbles left in a chamber filled with liquid hydrogen or other liquefied gas. It was invented in 1952 b...

barium

(Encyclopedia)barium bârˈēəm [key] [Gr.,=heavy], metallic chemical element; symbol Ba; at. no. 56; at. wt. 137.327; m.p. 725℃; b.p. 1,640℃; sp. gr. 3.5 at 20℃; valence +2. Barium is a soft, silver-white, ...

Fonseka, Sarath

(Encyclopedia)Fonseka, Sarath säˈrät fänsĕkˈä [key], 1950–, Sri Lankan general and politician. He joined the army in 1970 and rose through the officer corps. From the early 1980s he led Sri Lankan troops i...

Salam, Abdus

(Encyclopedia)Salam, Abdus, 1926–96, Pakistani physicist. After attending Government College at Lahore, he received a Ph.D. from Cambridge (1952). He taught in Lahore for three years before returning to England, ...

deodorizer

(Encyclopedia)deodorizer or deodorant, substance used to absorb or eliminate offensive odors. Disinfectants such as hydrogen peroxide, chlorine, and chlorine compounds eliminate odors caused by microorganisms. Adso...

Davy, Sir Humphry

(Encyclopedia)Davy, Sir Humphry, 1778–1829, English chemist and physicist. The son of a woodcarver, he received his early education at Truro and was apprenticed (1795) to a surgeon-apothecary at Penzance. While d...

Jovian planets

(Encyclopedia)Jovian planets, the planets Jupiter, Saturn, Uranus, and Neptune. They are all larger and more massive than the earth. Since they rotate faster, they are more flattened at the poles than are the terre...