Columbia Encyclopedia

(Encyclopedia) conglomerate, in geology, sedimentary rock composed largely of pebbles or other rounded particles whose diameter is larger than 2 mm (.08 in.). Essentially a cemented gravel, conglomerates are formed ...

(Encyclopedia) wave, in physics, the transfer of energy by the regular vibration, or oscillatory motion, either of some material medium or by the variation in magnitude of the field vectors of an electromagnetic fie...

(Encyclopedia) locust, in botany, any species of the genus Robinia, deciduous trees or shrubs of the family Leguminosae (pulse family) native to the United States and Mexico. The locusts have pendent clusters of flo...

(Encyclopedia) mesa māˈsə [key] [Span.,=table], name given in the SW United States to a small, isolated tableland or a flat-topped hill. Two or more of the sides are steep and usually perpendicular and some have ...

(Encyclopedia) pulse, alternate expansion and contraction of artery walls as heart action varies blood volume within the arteries. Artery walls are elastic. Hence they become distended by increased blood volume duri...

(Encyclopedia) turkey, common name for a large game and poultry bird related to the grouse and the pheasant. Its name derives from its “turk-turk” call. Turkeys are indigenous to the New World; American fossils ...

(Encyclopedia) ray, extremely flat-bodied cartilaginous marine fish, related to the shark. The pectoral fins of most rays are developed into broad, flat, winglike appendages, attached all along the sides of the head...

(Encyclopedia) mortar, in warfare, term originally applied to certain types of artillery with high trajectories, but later applied to an infantry weapon that consists of a tube supported by a bipod that fires a proj...

(Encyclopedia) fatigue, in engineering, microscopic cracking of materials, especially metals, after repeated applications of stress. Fissures may be formed within pieces of metal during their manufacture when, while...

(Encyclopedia)  CE5 Life cycle of a moss: A germinating spore forms a transitory branching structure on the soil surface, which develops into the conspicuous gametophyte, the familiar moss plant. Eggs and sperm ar...