Columbia Encyclopedia

Search results

25 results found

Archimedes

(Encyclopedia)Archimedes ärkm´dz [key], 287–212 BC, Greek mathematician, physicist, and inventor. He is famous for his work in geometry (on the circle, sphere, cylinder, and parabola), physics, mechanics,...

Archimedes' principle

(Encyclopedia)Archimedes' principle, principle that states that a body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid. The principle applies to both floating and submerged bo...

Archimedes' screw

(Encyclopedia)Archimedes' screw, a simple mechanical device believed to have been invented by Archimedes in the 3d cent. BC It consists of a cylinder inside of which a continuous screw, extending the length of the ...

buoyancy

(Encyclopedia)buoyancy boi´ns, boo´yn– [key], upward force exerted by a fluid on any body immersed in it. Buoyant force can be explained in terms of Archimedes' principle. ...

endless screw

(Encyclopedia)endless screw, screw fixed so that it cannot move longitudinally as it rotates. Thus, instead of the usual action in which a screw advances itself through a medium as it turns, the screw remains stati...

Tartaglia, Niccolò

(Encyclopedia)Tartaglia, Niccolò nk-klô´ tärtä´lyä [key], c.1500–1557, Italian engineer and mathematician. Largely self-educated, he taught mathematics at Verona, Brescia, and Venice. A pioneer in appl...

Hiero II

(Encyclopedia)Hiero II, d. c.215 BC, Greek Sicilian ruler, tyrant of Syracuse (c.270–c.215 BC). He showed such ability and distinction after Pyrrhus left Sicily (275 BC) that he was made commander in chief of the...

Aristarchus of Samos

(Encyclopedia)Aristarchus of Samos rstär´ks, rstär´ks, s´ms [key], fl. c.310 BC–c.230 BC, Greek astronomer and mathematician of the Alexandrian school. He is said to have been the first t...

Marcellus

(Encyclopedia)Marcellus märsl´s [key], principal plebeian family of the ancient Roman gens Claudia. Marcus Claudius Marcellus, c.268–208 BC, was consul five times. In his first consulship he fought (222) ag...

convection

(Encyclopedia)convection, mode of heat transfer in fluids (liquids and gases). Convection depends on the fact that, in general, fluids expand when heated and thus undergo a decrease in density (since a given volume...

Browse by Subject