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air plant

(Encyclopedia)air plant: see epiphyte.

air pollution

(Encyclopedia)air pollution, contamination of the air by noxious gases and minute particles of solid and liquid matter (particulates) in concentrations that endanger health. The major sources of air pollution are t...

heating

(Encyclopedia)CE5 Typical warm-air heating system heating, means of making a building comfortably warm relative to a colder outside temperature. Old, primitive methods of heating a building or a room within it ...

atomic mass unit

(Encyclopedia)atomic mass unit or amu, in chemistry and physics, unit defined as exactly 1⁄12 the mass of an atom of carbon-12, the isotope of carbon with six protons and six neutrons in its nucleus. One amu is e...

Mass, in Christianity

(Encyclopedia)Mass, religious service of the Roman Catholic Church, which has as its central act the performance of the sacrament of the Eucharist. It is based on the ancient Latin liturgy of the city of Rome, now ...

mass, in physics

(Encyclopedia)mass, in physics, the quantity of matter in a body regardless of its volume or of any forces acting on it. The term should not be confused with weight, which is the measure of the force of gravity (se...

mass-luminosity relation

(Encyclopedia)mass-luminosity relation, in astronomy, law stating that the luminosity of a star is proportional to some power of the mass of the star. More massive stars are in general more luminous. For stars on t...

center of mass

(Encyclopedia)center of mass, the point at which all the mass of a body may be considered to be concentrated in analyzing its motion. The center of mass of a sphere of uniform density coincides with the center of t...

fog

(Encyclopedia)fog, aggregation of water droplets or ice crystals immediately above the surface of the earth (i.e., a cloud near the ground). A light or thin fog is usually called a mist. Fog may occur when the mois...

sirocco

(Encyclopedia)sirocco sərŏkˈō [key] [Ital., from Arab. sharq=east], hot, dust-laden, dry, southerly wind originating in the N African desert (most commonly in the spring) and reaching Italy and nearby Mediterra...