FIND OUT MORELakes form where water fills hollows in the landscape. Some of these hollows are formed by glaciers gouging into the ground, and some are created when river valleys are blocked…
Downhill DiscoveriesIntermediate-Level Science ProjectsPhysical ScienceCan Water Make a Bottle Rocket Fly Higher?Downhill Discoveries The concepts of potential energy, kinetic energy, drag,…
Fossils are the remains or imprints of prehistoric plants or animals. They are found in sedimentary rock (rock formed from sand and mud), coal, tar, volcanic ash, fossilized tree sap or frozen in…
(Encyclopedia) forest, a dense growth of trees, together with other plants, covering a large area of land. The science concerned with the study, preservation, and management of forests is forestry. A…
(Encyclopedia) art conservation and restoration, the preservation of structurally sound works of art, the halting of processes that lead to the damage of works of art, and the repair of already…
(Encyclopedia) turtle, a reptile of the order Chelonia, with strong, beaked, toothless jaws and, usually, an armorlike shell. The shell normally consists of bony plates overlaid with horny shields.…
(Encyclopedia) specific gravity, ratio of the weight of a given volume of a substance to the weight of an equal volume of some reference substance, or, equivalently, the ratio of the masses of equal…
(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…
(Encyclopedia) shaft sinking, excavation from the surface of an opening in the earth. Shafts, which are generally vertical, are usually distinguished from tunnels, which are horizontal. Little…
(Encyclopedia) fire fighting, the use of strategy, personnel, and apparatus to extinguish, to confine, or to escape from fire.
Ancient Rome is known to have had a fire department consisting by the…
