The history of compass development

First, Sina

As early as 2000 years ago in the Han Dynasty (206 BC-220 AD), skilled craftsmen polished and chiseled magnets into spoon shapes, put them on a mirror-smooth chassis made of bronze, and then cast directional carvings. When the magnetic spoon stops rotating on the chassis, the handle of the spoon guides and the mouth of the spoon points north. This is the earliest musical instrument in the world invented by our ancestors, called Sina.

Second, the ancient compass

Later, the ancients made an ancient compass based on Sina. The compass at this time is very similar to the compass used now. It has a magnetic needle pointing in the direction and a dial showing the direction. Installing a compass on a ship can guide people to sail.

Third, guide blind fish.

About the early years of the Northern Song Dynasty, due to the needs of military affairs and navigation, as well as the development of materials and technology, artificial magnetic disks, needles and artificial magnetization were used to make guide fish, which was more advanced than Sina in performance and use.

Fourth, the compass.

Shortly after the invention of the guide fish, a compass with more significance, simpler manufacturing method, more convenient use and wider use was invented. Shen Kuo, a famous politician and scientist in the Northern Song Dynasty, recorded for the first time in the book Meng Qian Bi Tan (A.D. 1086) that grinding an iron needle with a natural magnet can make it point to the south. It is also described that the compass is not a complete guide, but slightly to the east. This is the phenomenon of magnetic declination.

Extended data

Principle: magnetic poles interact, the same name magnetic poles repel, and the different names magnetic poles attract. The earth itself is a huge magnet, called geomagnetism. The geomagnetic south pole is near the geographical north pole, and the geomagnetic north pole is near the geographical south pole. So when the small magnetic needle on the earth is at rest, one end always points to the north.

Usage: put the compass flat, there is no magnetic field interference around it, and then look at the pointer after the pointer swings. The direction corresponding to the south-north pointer is north and south; If marked with n and s, then n is north and s is south.

References:

Compass _ Baidu encyclopedia