Long before the invention of GPS satellites and other advanced positioning technologies, the compass was considered a simple and accurate solution for orientation in difficult geographical situations. Even today, this tool, which may be considered quite basic by many people, can save people from crisis in situations where there is no access to any kind of technology.
Despite its very accurate and effective performance, the compass has a very simple structure. A online compass to find north , unlike a gyroscope, consists of a small, lightweight magnet balanced on a frictionless axial surface. This magnet is usually called a needle and one end is marked with the letter N meaning north or painted with a different color. This is all that can be seen in the appearance of a compass.
Earth's magnetic field
But the function of the compass relies on a more interesting phenomenon. If you imagine the earth as a container inside which a giant bar magnet is hidden, in order for the north end of the compass needle to show the north direction, you should imagine that the south pole of the magnet buried in the earth is facing north. In this way, by using the law of attraction of opposite poles of the magnet, the function of the compass can be justified, in other words, the north end of the compass needle is attracted to the south end of the magnet hidden in the ground, and in this way the tool can display the north pole.
To add more details, it is better to know that the bar magnet inside the earth is not exactly on the earth's rotation axis and is slightly off center. This deviation is called inclination and most detailed maps of different regions show this tendency to deviate from the center.
The Earth's magnetic field is not very strong on the surface, because the Earth has a diameter of 12,784 km, so the Earth's magnetic field has to travel a long distance to affect the performance of a compass on the surface. This is why the compass needle must be very light weight and mounted on a frictionless surface, otherwise the Earth's magnetic field will not be able to move it.
The example of a bar magnet is only used to explain the simple operation of a compass, but the main thing that moves the compass needle is not this imaginary magnet. It is not yet known exactly what happens inside the earth when the compass needle moves on the earth, but there are theories in this field that may be able to explain this event better.
Earth's core contains a large amount of molten iron, but deep in this core, the pressure is so high that this molten iron turns into a frozen crystal. The transfer of heat caused by nuclear radiation along with the rotation of the earth leads to the movement of molten iron in a rotational path. It is said that these rotational forces in molten iron create weak magnetic forces around the axes of rotation.
Hence, it is said that because the Earth's magnetic field is weak at the surface of the planet, the compass is nothing more than a very weak magnetic field detector that anything can generate, and hence it can be made into a small magnetic field tracking device. Also used by coils.
Gyroscopic compass
Using magnetic compasses in moving spaces such as ships and airplanes can be troublesome, because this tool must be used on a completely flat surface, and creating the smallest angle on the surface will cause the compass to adjust itself to the new angle and display new information that It may be incorrect. Therefore, most ships and airplanes are equipped with gyroscopic compasses.
Gyroscope or direction indicator can accurately display the angle and direction despite the movement, this is done by the motor that is placed inside the gyroscope compass and keeps the gyroscope active, in this way you move this tool in any direction. Its hand will always show north with high accuracy and it can adapt to the direction of north according to existing movements.
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