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Polke, Sigmar

(Encyclopedia)Polke, Sigmar, 1941–2011, innovative German artist best known for his paintings and photography. His family immigrated from East to West Germany in 1953, and he lived in Düsseldorf, studying (1961â...

distillation

(Encyclopedia)distillation, process used to separate the substances composing a mixture. It involves a change of state, as of liquid to gas, and subsequent condensation. The process was probably first used in the p...

Neptune, in astronomy

(Encyclopedia)Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolut...

ultraviolet astronomy

(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...

radio-frequency identification

(Encyclopedia)radio-frequency identification (RFID), a technology that uses radio waves to transmit data and uniquely identify an animal, person, or thing. An RFID system typically consists of a tag and a reader. T...

carbon dioxide

(Encyclopedia)carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. It does not bur...

atmosphere

(Encyclopedia)CE5 Atmosphere atmosphere [Gr.,=sphere of air], the mixture of gases surrounding a celestial body with sufficient gravity to maintain it. Although some details about the atmospheres of other plane...

hypothalamus

(Encyclopedia)hypothalamus hīˌpəthălˈəməs [key], an important supervisory center in the brain, rich in ganglia, nerve fibers, and synaptic connections. It is composed of several sections called nuclei, each ...

ice cream

(Encyclopedia)ice cream, sweet frozen dessert, made from milk fat and solids, sugar, flavoring, a stabilizer (usually gelatin), and sometimes eggs, fruits, or nuts. The mix is churned at freezing temperature to att...

antifreeze

(Encyclopedia)antifreeze, substance added to a solvent to lower its freezing point. The solution formed is called an antifreeze mixture. Antifreeze is typically added to water in the cooling system of an internal-c...