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citric acid

(Encyclopedia)citric acid or 2-hydroxy-1,2,3-propanetricarboxylic acid, HO2CCH2C(OH)(CO2H)CH2CO2H, an organic carboxylic acid containing three carboxyl groups; it is a solid at room temperature, melts at 153℃, an...

emotion

(Encyclopedia)emotion, term commonly and loosely used to denote individual, subjective feelings which dictate moods. In psychology, emotion is considered a response to stimuli that involves characteristic physiolog...

saturated fat

(Encyclopedia)saturated fat, any solid fat that is an ester of glycerol and a saturated fatty acid. The molecules of a saturated fat have only single bonds between carbon atoms; if double bonds are present in the f...

silver chloride

(Encyclopedia)silver chloride, chemical compound, AgCl, a white cubic crystalline solid. It is nearly insoluble in water but is soluble in a water solution of ammonia, potassium cyanide, or sodium thiosulfate (“h...

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...

pineal gland

(Encyclopedia)pineal gland pĭnˈeəl [key], small organ (about the size of a pea) situated in the brain. Long considered vestigial in humans, the structure, which is also called the pineal body or the epiphysis, i...

thermite

(Encyclopedia)thermite [from Thermit, a trade name], mixture of powdered or granular aluminum metal and powdered iron oxide. When ignited it gives off large amounts of heat. In wartime it has been used in incendiar...

nose

(Encyclopedia)nose, olfactory and respiratory organ, located between the eyes. The external nose, composed of bone and cartilage, is the most prominent feature of the face in humans. The internal nose is a hollow s...

bean weevil

(Encyclopedia)bean weevil, common name for a well-known cosmopolitan species of beetle (Acanthoscelides obtectus) that attacks beans and is thought to be native to the United States. It belongs to the family Bruchi...

Carlsbad Caverns National Park

(Encyclopedia)Carlsbad Caverns National Park, 46,766 acres (18,940 hectares), SE N.Mex., in the Guadalupe Mts.; designated a national park in 1930. These connecting limestone caves, with remarkable stalactite and s...