The magnetic compass is an outstanding invention of ancient Chinese thinkers. Naturally, in our days the device is not used as often as in the past centuries. However, it is sometimes difficult for tourists, pilots and sailors to do without it. What is a magnetic compass? What is the principle of the device? What are the features of its application? Let's figure it out together.
A brief excursion into history
The device, which is the prototype of a modern magnetic compass, was developed in the III century BC. At this time, Chinese inventors managed to construct a device that indicated the cardinal points. The ancient device consisted of a magnetite spoon, which on one side contained a convex spherical part, and on the other a thin stalk. The element was laid on a polished copper plate with markings in the form of cardinal points. Being in free rotation, the handle of the spoon always stopped, pointing to the south.
As you can see, the first magnetic compass had a primitive structure. The device had a whole host of disadvantages. The magnetite from which the rotating spoon was made was difficult to process. In turn, friction was created between the convex part of such a direction indicator and the surface of the marked plate. Therefore, the compass pointed south with significant errors.
The invention was thoroughly developed in the XI century. A Chinese scientist named Shen Gua proposed using a magnetized needle as a pointer to the cardinal points. The latter was freely fixed on a thin silk thread. The thinker explained the fact that the tip of the needle always points to the south by the mismatch of the magnetic and geographical meridians.
In the XIII century, the magnetic compass became widely used by European sailors. If at first the device consisted only of a magnetized needle that rotated suspended on a thread or floated in a vessel on a piece of wood, then later the structure began to be placed in a case closed by glass.
The Italian inventor Flavo Giulio made a huge contribution to the improvement of the magnetic compass. It was he who proposed to place a moving magnetic pointer in the middle of a round dial, which was divided into separate sectors, according to the cardinal points. Later, the compass needle began to be fixed on the gimbal, which contributed to obtaining more accurate indicators during rolling on ships.
Operating principle
In a modern compass, the magnetic needle is fixed on the axis. Since the element is in free movement, it is required to choose a control direction from which the movement to the target will be conducted. In the magnetic compass, this is a conditional line that connects the South and North Poles of the planet. When holding the device in a static position, the arrow will always stop parallel to the specified line. Deviations of the pointer can be observed only in the vicinity of magnets or metal objects.
Compass scale
In order to determine the exact indicators, the magnetic compass needle moves along the so-called card. The latter is a circular dial that contains 360 divisions. Each of them corresponds to one degree. Counting is from zero according to the clockwise movement. Pointer to the north corresponds to a division of 0 about . East direction is determined by the mark of 90 °. The south can be identified by a value of 180 °, and the division of 270 ° indicates to the west. The presented values are called the main compass points. It is on them that the cardinal points are determined.
How to check the compass?
To determine the operability of the device, it is necessary to place the compass in the magnetic field of another object. It can be a metal product or a piece of magnet. It is important that the compass needle initially lie parallel to the north-south axis.
To check the device, it is necessary to lay it on a flat surface, waiting for the direction indicator to stop. Further, it is enough to bring an object with its own magnetic field to the compass. As soon as the arrow starts to rotate, you need to remove the thing. If then the pointer returns to its original position, it means that the compass is working properly.
Compass application
How to use a compass? The Earth's magnetic field allows you to find the correct landmarks in any part of the world. In order not to get lost, it is enough to note for oneself the starting point at the beginning of the movement. It can be any landmark, for example, a settlement, a highway, a river. From the starting point you need to move a few dozen steps in the right direction and turn around. Then it remains to put the compass on a flat surface and turn it so that the arrow lies parallel to the north-south direction. As soon as this happens, it will become clear which degree on the scale of the device corresponds to the starting point, and which target rate. These numbers must be remembered, because they will become important if you have to move back along this conditional line.
Useful Tips
There are a number of practical recommendations for using the compass:
- When using a magnetic device, you should always remember that external factors can affect the accuracy of its indicators. For example, if in the course of determining the coordinates behind a person’s back there is a backpack that contains a whole mass of metal objects, the arrow, which should point to the north, may fail. The result will be a person walking in a circle or moving with a significant deviation from the target.
- Using a magnetic compass, you should always take into account the presence of nearby high-voltage lines of electrical voltage. To avoid inaccuracies in the performance of the device, it is enough to move away from the wires to a distance of about 50 meters.
- Before hiking, it is extremely important to check whether everything is in order with the compass. Perhaps, in the course of the previous use, the device received damage that would interfere with the reading of indicators.
Finally
So we found out what a magnetic compass is and how to use the device correctly. In order to always find the right direction in unfamiliar areas, it is important to regularly exercise using such a device, to train observation and visual memory.
In conclusion, it is worth noting that few people continue to use magnetic compasses today. Indeed, such once-indispensable devices were replaced by multifunctional GPS-navigators, which are much easier to master. However, not everyone can afford such expensive devices. At the same time, the batteries of electronic navigators are often discharged at the most inopportune moment. It is in such situations that the good old compass will come to the rescue, with which you can find the way home.