Columbia Encyclopedia

Search results

128 results found

fulminate

(Encyclopedia)fulminate fŭlˈmĭnāt [key], any salt of fulminic acid, HONC, a highly unstable compound known only in solution. The term is most commonly applied to the explosive mercury (II) fulminate, also calle...

wheel and axle

(Encyclopedia)CE5 Wheel and axle wheel and axle, simple machine consisting of a wheel mounted rigidly upon an axle or drum of smaller diameter, the wheel and the axle having the same axis. It is fundamentally a...

hydraulics

(Encyclopedia)hydraulics, branch of engineering concerned mainly with moving liquids. The term is applied commonly to the study of the mechanical properties of water, other liquids, and even gases when the effects ...

Callias, d. c.370 b.c., Athenian leader

(Encyclopedia)Callias, d. c.370 b.c., Athenian leader, one of the generals of the Peloponnesian War. In his old age Callias was one of the ambassadors sent to Sparta with Callistratus to negotiate a peace treaty in...

intermolecular forces

(Encyclopedia)intermolecular forces, forces that are exerted by molecules on each other and that, in general, affect the macroscopic properties of the material of which the molecules are a part. Such forces may be ...

inclined plane

(Encyclopedia)CE5 Inclined plane inclined plane, simple machine, consisting of a sloping surface, whose purpose is to reduce the force that must be applied to raise a load. To raise a body vertically a force mu...

superfluidity

(Encyclopedia)superfluidity, tendency of liquid helium below a temperature of 2.19K to flow freely, even upward, with little apparent friction. Helium becomes a liquid when it is cooled to 4.2K. Special methods...

nail, in carpentry

(Encyclopedia)nail, metal pin driven by force applied at one end into pieces of material, usually wood, to join them together. The strength of a nailed joint depends on the properties of the wood, the type and numb...

Eyskens, Gaston

(Encyclopedia)Eyskens, Gaston gästôNˈ īˈskəns [key], 1905–88, Belgian political leader. He became a professor at the Univ. of Louvain in 1931. A Christian Socialist member of parliament (1939–73), he head...

grease

(Encyclopedia)grease, mixture of lubricant and thickener. It is used to reduce friction between surfaces from which oils would leak away or cause damage by dripping, or where lubrication must be assured for extende...