Columbia Encyclopedia

Search results

500 results found

mirror

(Encyclopedia)mirror, in optics, a reflecting surface that forms an image of an object when light rays coming from that object fall upon it (see reflection). Usually mirrors are made of plate glass, one side of whi...

plane

(Encyclopedia)plane, in mathematics, flat surface of infinite extent but no thickness. An example of a plane, or more exactly of a bounded portion of a plane, is the surface forming one face, or side, of a cube. A ...

temperature

(Encyclopedia)CE5 Temperature scales temperature, measure of the relative warmth or coolness of an object. Temperature is measured by means of a thermometer or other instrument having a scale calibrated in unit...

zenith

(Encyclopedia)zenith, in astronomy, the point in the sky directly overhead; more precisely, it is the point at which the celestial sphere is intersected by an upward extension of a plumb line from the observer's lo...

Pacific Grove

(Encyclopedia)Pacific Grove, residential and resort city (1990 pop. 16,117), Monterey co., W central Calif., on a point where Monterey Bay meets the Pacific Ocean; inc. 1889. Among the natural attractions of the ar...

decimal system

(Encyclopedia)decimal system [Lat.,=of tenths], numeration system based on powers of 10. A number is written as a row of digits, with each position in the row corresponding to a certain power of 10. A decimal point...

solid-state physics

(Encyclopedia)solid-state physics, study of the properties of bulk matter rather than those of the individual particles that compose it. Solid-state physics is concerned with the properties exhibited by atoms and m...

Assos

(Encyclopedia)Assos –əs [key], ancient city, Mysia, NW Asia Minor, on the Gulf of Adramyttium E of Point Lectum, westernmost point of Asia. ...

Davis, George Breckenridge

(Encyclopedia)Davis, George Breckenridge, 1847–1914, American army officer and jurist, b. Ware, Mass., grad. West Point, 1871. His early military service was divided between duty on the Western frontier and teach...

gamma-ray astronomy

(Encyclopedia)gamma-ray astronomy, study of astronomical objects by analysis of the most energetic electromagnetic radiation they emit. Gamma rays are shorter in wavelength and hence more energetic than X rays (see...