spark plug: see ignition.

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 are maintained with high voltage between alternate layers. A high-pressure gas fills the gaps between the plates and is ionized along the path of the traversing charged particle. As a result, sparks jump between adjacent, oppositely charged plates and the trail of sparks left by the particle is seen as a series of dashes. The spark chamber has replaced the bubble chamber in certain applications. Although the particle paths are recorded more accurately in the bubble chamber, the bubble chamber indiscriminately records all events that occur in a comparatively long interval. The spark chamber operates much more rapidly and can be made highly selective by using auxiliary detectors to screen out unwanted events. Because of its selectivity, the spark chamber is most useful in searching for very rare events. Spark chambers can be highly automated, with data collected and stored electronically instead of photographically, as is necessary with the bubble chamber. The analysis of the data can then be accomplished by a high-speed computer, which may operate simultaneously with the experiment and thereby provide immediate evaluation of the quality of the data and allow optimum operating conditions to be maintained at all times.

spark, in electricity: see arc.

Spark, Dame Muriel, 1918-2006, Scottish novelist, b. Muriel Sarah Camberg. She lived in Edinburgh, Rhodesia (now Zimbabwe), London, New York, and Rome, and spent her last years in Tuscany. Spark's typically short, spare, and witty novels expose the pretensions, hypocrisies, and petty foibles of her characters with merciless satire and cool detachment. Her Roman Catholicism (she converted in 1954) informs her acute moral vision and underlies her interest in revealing the dark, terrifying, evil, and unexplainable side of banal human experience. Spark's more than 20 novels include The Comforters (1957), Memento Mori (1958), The Bachelors (1960), The Girls of Slender Means (1963), The Mandelbaum Gate (1965), The Abbess of Crewe (1974), The Takeover (1976), Loitering with Intent (1981), A Far Cry from Kensington (1988), Reality and Dreams (1997), Aiding and Abetting (2001), and The Finishing School (2004). Her short novel The Prime of Miss Jean Brodie (1961) became an acclaimed stage, film, and television production. Her poems and short stories are compiled in Collected Poems I (1967), Collected Stories I (1968), and Open to the Public: New and Collected Stories (1997, rev. ed. 2001). She also wrote critical studies of Mary Shelley (1951) and John Masefield (1953) and a biography of Emily Brontë (1953). She was made a Dame of the British Empire in 1993.

Device that fits into the cylinder head of an internal-combustion engine and carries two electrodes separated by an air gap, across which current from a high-tension ignition system discharges, creating a spark and igniting the fuel. The electrodes and the insulator separating them must withstand high temperatures, as well as an electric stress of up to several thousand volts. Spark-gap length affects the energy of the spark, and the shape of the insulator affects the temperature of operation.

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orig. Muriel Sarah Camberg

(born Feb. 1, 1918, Edinburgh, Scot.—died April 13, 2006, Florence, Italy) British writer. She spent several years in Central Africa, returning to Britain during World War II. Until 1957 she published only poetry and criticism, including studies of Mary Shelley and the Brontë sisters. Her fiction uses satire and wit to present serious themes, often questions about good and evil. Memento Mori (1959) is her most widely praised novel; the best-known is The Prime of Miss Jean Brodie (1961; film, 1969). Her later novels, often more sinister in tone, include The Abbess of Crewe (1974), A Far Cry from Kensington (1988), and Reality and Dreams (1996).

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orig. Muriel Sarah Camberg

(born Feb. 1, 1918, Edinburgh, Scot.—died April 13, 2006, Florence, Italy) British writer. She spent several years in Central Africa, returning to Britain during World War II. Until 1957 she published only poetry and criticism, including studies of Mary Shelley and the Brontë sisters. Her fiction uses satire and wit to present serious themes, often questions about good and evil. Memento Mori (1959) is her most widely praised novel; the best-known is The Prime of Miss Jean Brodie (1961; film, 1969). Her later novels, often more sinister in tone, include The Abbess of Crewe (1974), A Far Cry from Kensington (1988), and Reality and Dreams (1996).

Learn more about Spark, Dame Muriel with a free trial on Britannica.com.