ZOL 303 Study Guide - Final Guide: Longitudinal Wave, Clay Minerals, Leading Edge
Document Summary
History of oceanography: determination of latitude. Measure of angular distance from the equator. Latitude determined as the angle between the north star and horizon: determination of longitude. Greenwich defined as the prime meridian: globe divided into east and west halves. Can determine longitude each day at noon. Example: ship sails west from england, at noon chronometer reads 16:18 (4:18 pm, 4 hr. x 15 /hr. = 60 of longitude: 18 min x . 25 /min =4. 5 , total = 64. 5 w longitude, circumference of the earth. Syene, sun shines directly onto water in a deep well on longest day. Alexandria, vertical pole casts a shadow: 7. 2 = 1/50th of a circle, assumed sun"s rays parallel, alexandria directly north of syene. Length of stadia uncertain but if egyptian stadium (157. 5 m) used then circumference =39690 km. Distance between syene and alexandria was ~ 800 km: 7. 2 /800 km = 360 /circumference of earth (40,000 km)
