An instrument that has a magnetized needle that rotates about a center and that points to magnetic north is known as a compass, this allows to specify the orientation of the earth's surface. During the 20th century, the magnetic compass began to be replaced by more developed and complete navigation methods, such as the gyroscopic compass, for example, which is graduated with laser beams and global posture methods. Although, it is still the most common in activities that demand great movement or that due to their nature, prevent the entry of electrical energy, which depends on the rest of the systems.
It is important to note that the term compass in English is called “ compass ” and it is the main navigation tool used by sailors to mark their location on the map. Through the map it is possible to determine the exact place where the ship is located and based on that information, to be able to establish the direction in which it should be navigated.
At present, in addition to the conventional ones, you can also find the virtual compass, (which is used by a mobile device or smartphone), as well as other sensors such as the gyroscope or the accelerometer.
History of the compass
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The compass was created in China during the 9th century with the purpose of determining the orientation in the open sea, at the beginning it was a magnetized needle floating in a container covered with water. Later it was modernized to reduce its size and facilitate use, replacing the water container with a rotating center to calculate the direction.
Today they have adopted small improvements that, although they do not alter their activity system, make the measurements easier to perform. Among these improvements is the lighting system which is used to facilitate vision when capturing data in dark places, and there are also the optical methods for calculations in which the references are elements located at long distances.
The magnetized water used today arose in China between 850 and 1050, where its use quickly spread among sailors, who supplement their direction through the stars with the compass. One of the first subjects known to have used the compass was the marine crew member Zheng He, who lived in the Chinese province of Yunnan, and who made countless trips through the ocean between 1405 and 1433.
Parts of a compass
Base
It is the part that holds the entire compass, fundamentally it is made of solid, transparent plastic that makes it easier to see the map where it rests.
The ring
It is a 360 ° round band that approves obtaining an exact calculation, usually it has been located parallel to the base, which allows it to rotate without having any kind of inconvenience, being able to determine distances.
Magnetic or magnetized needle
It is located inside the cylinder, where the rotating ring is also located. The needle is immersed in oil, so that the inertia displacement achieves a deceleration as soon as possible, but without stopping the needle completely.
Oil or watery liquid
It helps the needle to move without tripping over the other pieces, otherwise it would lose its magnetic qualities. It also helps decelerate the needle, but without stopping.
Orienting arrow
In the inner part of the cylinder there is an arrow called "orientation arrow", it is on the bottom of the magnetized needle. To find its place, it is usually highlighted by a double line similar to an arrow.
The reading point
It is used to make annotations about a specific reference point. This is colored white and is located above the rotating ring.
Travel direction arrow
This is the opposite of the orienting arrow, as it passes through a fraction of the plastic base and ends with a single arrow.
How a compass works
Compasses work with the planet's natural magnetic fields. The earth has an iron core, one part of which is solid crystal and the other part is liquid. The activity in the liquid core is thought to be what causes the planet's magnetic field. Like all magnetic fields, the earth's field has two main poles, which are the north pole and the south pole.
Compass needles usually have two parts, one is polychrome red and the other part is white or black. The red polychrome part of the needle will always be pointing to the planet's magnetic north. However, it is very important to note that magnetic north is different for each space on earth, and different from geographic north, which is located at the north pole.
