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Ruian Shunfeng Navigation Instruments Co.,Ltd

Add: No.20, Heping Road, Jinhu Street, Ruian, Zhejiang, China
Con: april Zhang
Tel: +86-577-65520898
Fax: +86-577-65966926
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What Is A Magnetic Compass?

What Is A Magnetic Compass 

A compass is an extremely simple device. The magnetic compass (contrary to the gyro compass) is placed on the fulcrum of little friction by a very small, light magnet balance. Magnets are often referred to as pointers. At one end of the pointer is labeled "n" meaning north, or painted other colors to indicate that it is pointing to the north. On the face of it, this is all the compass.

The reasons for the compass work are much more interesting. It can be imagined that a giant bar magnet is buried inside the earth. To make the compass North Point to the Arctic, it is necessary to assume the south end of the strip magnet buried in the Arctic, as shown in the right illustration. If you understand the world, you will find that electromagnetic universal "heterosexual suction" laws will make the north end of the compass Pointer to the south end of the embedded strip magnet. So the compass will always point to the Arctic.

Precisely, the bar magnet is not exactly coincident with the rotation axis of the Earth, but is slightly deviated from the center. This deviation is called deviation, and most high-quality maps indicate how much different regional deviations are (because there are tiny differences in different positions on Earth).

The Earth's magnetic field is fairly faint on the surface of the Earth. After all, the planet is almost more than 13,000 kilometers in diameter, so the magnetic field takes a long distance to affect the compass. This is why the compass needs to be very lightweight magnets and no friction support. Otherwise, the magnetic field strength of the Earth's surface is insufficient to rotate the pointer.

Although the metaphor of "giant bar magnets buried at the core" explains why the earth has a magnetic field, it is not the case. So what is the real situation?

No one knows exactly, but there is a working principle that is widely circulated. As mentioned above, people think that the core of the earth is composed of molten iron (red). But at its core, the pressure is so much that the iron crystals of ultra high temperatures become solids. The heat emitted from the core produces convection and the rotation of the earth, so that the liquid iron enters into the rotation mode. It is believed that these rotating forces in the liquid iron layer weaken the magnetic force around the rotary shaft.

The fact is that the Earth's magnetic field is so weak, and the compass is only a detector that can detect the faint magnetic field generated by anything. That's why we can use a compass to detect a small magnetic field generated by a charged wire.

Ruian shunfeng navigation instruments co.,ltd


Con:april Zhang




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