Compass, ancient time calls department south, main component is one installs the magnetic needle on the axis, the magnetic needle leaves OK and free roll in the action of natively magnetic field and maintain the tangent direction in magnetism meridian to go up, the arctic of the magnetic needle points to geographical antarctic, use this one function to be able to discern direction. Sea of commonly used Yu Hang, earth is measured, the respect such as journey and military affairs. The invention of the compass that direction indicates on physics has 3 kinds of parts, it is department respectively south, compass and magnetic needle, all belong to Chinese invention. According to " ancient mine is recorded " the magnetism hill that account appears the earliest at period of the Warring States is taken. Manage namely because of the compass previously south, magnetism spoon rotates dormant hind, what spoon handle points to is southern, later for nautical wait after pointing to convenient demand to improve, appellation is suitable call compass, actually the west makes compass. Compass application is in boat is maritime, it is round-the-clock navigation tool, made up for the inadequacy of navigation of article of astronavigation, ground, initiated nautical history epochal. In the meantime, nautical activity also promoted the development of compass further. The earth is a large magnetic body, antarctic of its terrestrial magnetism is near geographical arctic, geomagnetic arctic is near geographical antarctic. | | | Compass suffers the effect of magnetic field force in earthly magnetic field, so one aspect of the matter of guideline of meeting one aspect of the matter points to north. Https://haohuo.snssdk.com/views/product/item2.html? Id=3299009051727403814&tt_project_id=6&origin_type=604