What material is the compass made of?

The main material is a magnet. The principle is to install a magnetic needle on the shaft. Under the action of natural geomagnetic field, the magnetic needle can rotate freely and keep in the tangential direction of magnetic meridian. The north pole of the magnetic needle points to the north pole, and the direction can be distinguished by this property.

The appearance of magnetic orientation instrument makes people change from passive orientation of observing celestial bodies to active orientation using geomagnetism. Compasses are often used in navigation, geodesy, travel and military affairs. The invention of the compass with physical direction indication has three parts, namely Sina, compass and magnetic needle, all of which belong to the invention of China. In ancient China, the compass was first used for rituals, etiquette, military affairs and divination, and to determine the orientation when looking at geomantic omen.

Extended data

Modern compass

Modern people have made all kinds of electronic compasses. Smartphones generally have this software. Electronic compass, also known as digital compass, is a method to determine the North Pole by using geomagnetic field. When applied to a mobile phone, it is actually an electronic compass. An electronic compass generally consists of a magnetoresistive sensor and a fluxgate.

Electronic compass can be divided into plane electronic compass and three-dimensional electronic compass. The plane electronic compass requires the user to keep the compass level when using it, otherwise, when the compass is tilted, it will also give the change of course, but in fact the course has not changed. There is an inclination sensor in the three-dimensional electronic compass. If the compass is tilted, it can compensate the tilt of the compass, so that the heading data is still accurate even if the compass is tilted.

The angle between the magnetic meridian circle at any point on the earth's surface and the geographical meridian circle is the magnetic declination. The magnetic declination is not constant in the same place, and the magnetic declination measured in the morning and evening is slightly different every day. Magnetic declination has the characteristics of long-term variation and periodic variation. Magnetic declination is greatly influenced by geomagnetic environment. Due to the characteristics of geomagnetism, magnetic meridian is complex and non-parallel. The longer the straight line, the greater the error.

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