half-spherical
91Flat Earth — For other uses, see Flat Earth (disambiguation). The Flammarion engraving (1888) depicts a traveller who arrives at the edge of a flat Earth and sticks his head through the firmament …
92Cylindrical coordinate system — A cylindrical coordinate system with origin O, polar axis A, and longitudinal axis L. The dot is the point with radial distance ρ = 4, angular coordinate φ = 130°, and height z = 4. A cylindrical coordinate system is …
93Inventions in medieval Islam — A significant number of inventions were developed in the medieval Islamic world, a geopolitical region that has at various times extended from Al Andalus and Africa in the west to the Indian subcontinent and Malay Archipelago in the east.… …
94Logic and the philosophy of mathematics in the nineteenth century — John Stillwell INTRODUCTION In its history of over two thousand years, mathematics has seldom been disturbed by philosophical disputes. Ever since Plato, who is said to have put the slogan ‘Let no one who is not a geometer enter here’ over the… …
95Cherry bomb — For other uses, see Cherry bomb (disambiguation). Cherry Bombs (also known as Globe Salutes or Kraft Salutes) are approximately spherical shaped exploding fireworks, ranging in size from three quarters inch to one and one half inch (1.9 cm… …
96comet — cometary /kom i ter ee/, cometic /keuh met ik/, cometical, adj. cometlike, adj. /kom it/, n. Astron. a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and… …
97Pythagoreans and Eleatics — Edward Hussey PYTHAGORAS AND THE EARLY PYTHAGOREANS Pythagoras, a native of Samos, emigrated to southern Italy around 520, and seems to have established himself in the city of Croton. There he founded a society of people sharing his beliefs and… …
98Island of stability — The island of stability is a term from nuclear physics that describes the possibility of elements with particularly stable magic numbers of protons and neutrons. This would allow certain isotopes of some transuranic elements to be far more stable …
99Corrective lens — A bifocal corrective eyeglass lens A pair of contact le …
100electromagnetic radiation — Physics. radiation consisting of electromagnetic waves, including radio waves, infrared, visible light, ultraviolet, x rays, and gamma rays. [1950 55] * * * Energy propagated through free space or through a material medium in the form of… …
