Columbia Encyclopedia

Search results

500 results found

hypertension

(Encyclopedia)hypertension or high blood pressure, elevated blood pressure resulting from an increase in the amount of blood pumped by the heart or from increased resistance to the flow of blood through the small a...

formaldehyde

(Encyclopedia)formaldehyde fôrmălˈdəhīdˌ [key], HCHO, the simplest aldehyde. It melts at −92℃, boils at −21℃, and is soluble in water, alcohol, and ether; at STP, it is a flammable, poisonous, colorle...

Daguerre, Louis Jacques Mandé

(Encyclopedia)Daguerre, Louis Jacques Mandé lwē zhäk mäNdāˈ dägârˈ [key], 1789–1851, French scene painter and physicist, inventor of the daguerreotype, a photograph produced on a silver-coated copper pla...

fuel injection

(Encyclopedia)fuel injection, system in an internal-combustion engine that delivers fuel or a fuel-air mixture to the cylinders by means of pressure from a pump. It was originally used in diesel engines because of ...

nosebleed

(Encyclopedia)nosebleed, nasal hemorrhage occurring as the result of local injury or disturbance. Most nosebleeds are not serious and occur when one of the small veins of the septum (the partition between the nostr...

Bergius, Friedrich Karl Rudolf

(Encyclopedia)Bergius, Friedrich Karl Rudolf, 1884–1949, German chemist, Ph.D. Univ. of Leipzig, 1907. In 1910, Bergius set up a laboratory to carry out his research and in 1914 transferred the operation to the E...

kinetic-molecular theory of gases

(Encyclopedia)kinetic-molecular theory of gases, physical theory that explains the behavior of gases on the basis of the following assumptions: (1) Any gas is composed of a very large number of very tiny particles ...

Henry's law

(Encyclopedia)Henry's law, chemical law stating that the amount of a gas that dissolves in a liquid is proportional to the partial pressure of the gas over the liquid, provided no chemical reaction takes place betw...

dysprosium

(Encyclopedia)dysprosium dĭsprōˈzēəm [key] [Gr.,=hard to get at], metallic chemical element; symbol Dy; at. no. 66; at. wt. 162.500; m.p. 1,412℃; b.p. 2,562℃; sp. gr. 8.54 at 25℃; valence+3. Dysprosium i...

Newtown

(Encyclopedia)Newtown, town (1990 pop. 20,779), Fairfield co., SW Conn., on the Housatonic; inc. 1711. Pressure gauges, plastics, and paper and metal products are made, and dairy and fruit farms are in the area. In...