Which direction does the red pointer of the compass point?

The red pointer of the compass points to the north.

I. Introduction of compass

Compass, called Sina in ancient times, is mainly composed of magnetic needles installed 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 south pole of the magnetic needle points to the geographical south pole (magnetic north pole), and the direction can be distinguished by using this property.

It is often used in navigation, geodesy, tourism 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. According to ancient mine records, it first appeared in the Cishan area during the Warring States Period.

Second, the role of the compass

Compass is the result of China ancient working people's understanding of magnet magnetism in long-term practice. As one of four great inventions of ancient china, its invention has played an inestimable role in the development of human science, technology and civilization. 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.

Modern electronic compass and magnetic declination;

1, modern electronic 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. Although the plane electronic compass has high requirements for use, it is also a good choice if the carrier attached to the compass can always be horizontal.

2. Magnetic declination

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. Meteorological conditions also have a great influence on the magnetic declination, especially in lightning weather.