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zirconium

(Encyclopedia)zirconium zərkōˈnēəm [key], metallic chemical element; symbol Zr; at. no. 40; at. wt. 91.224; m.p. about 1,852℃; b.p. 4,377℃; sp. gr. 6.5 at 20℃; valence +2, +3, or +4. Zirconium is a very ...

silver

(Encyclopedia)silver, metallic chemical element; symbol Ag [Lat. argentum]; at. no. 47; at. wt. 107.8682; m.p. 961.93℃; b.p. 2,212℃; sp. gr. 10.5 at 20℃; valence +1 or +2. Pure silver is nearly white, lustrou...

wool

(Encyclopedia)wool, fiber made from the fleece of the domestic sheep. In the United States, by the Wool Products Labeling Act of 1939, the term wool may be applied only to fabrics made entirely of new wool; t...

rock

(Encyclopedia)rock, aggregation of solid matter composed of one or more of the minerals forming the earth's crust. The scientific study of rocks is called petrology. Rocks are commonly divided, according to their o...

hydrogen

(Encyclopedia)hydrogen hīˈdrəjən [key] [Gr.,=water forming], gaseous chemical element; symbol H; at. no. 1; interval in which at. wt. ranges 1.00784–1.00811; m.p. −259.14℃; b.p. −252.87℃; density 0.08...

Nebraska

(Encyclopedia)CE5 Nebraska nəbrăsˈkə [key], Great Plains state of the central United States. It is bordered by Iowa and Missouri, across the Missouri River (E), Kansas (S), Colorado (SW), Wyoming (NW), and S...

Columbus

(Encyclopedia)Columbus. 1 City (2020 pop. 206,922), seat of Muscogee co., W Ga., at the head of navigation on the Chattahoochee River; settled and inc. 1828 on the ...

fiber

(Encyclopedia)fiber, threadlike strand, usually pliable and capable of being spun into a yarn. Many different fibers are known to be usable; some 40 of these are of commercial importance, and others are of local or...

Novgorod

(Encyclopedia)Novgorod nôvˈgərət [key], city (1989 pop. 229,000), capital of Novgorod region, NW European Russia, on the Volkhov River near the point where it leaves Lake Ilmen. Novgorod's industries produce ch...

Sumer

(Encyclopedia)Sumer so͝o-mērˈēən [key]. The term Sumer is used today to designate the southern part of ancient Mesopotamia. From the earliest date of which there is any record, S Mesopotamia was occupied by a ...