- Brand: Freewind
- Item No .: 00936
- made in China
- Price tag: 56
- Sports outdoor projects: bicycle cross-country walking camping mountain climbing upstream travel
- Time to market: Spring 2014
- Purpose: Point to navigation
- Waterproof: Yes
- Whether the shock: Yes
- Whether the luminous display: Yes
- Portable: handheld
- Display: pointer type
"Name"Hardcover compass compass
MaterialCopper shell, plating 14K gold
"specification"Diameter 57mm, height 12mm
"weight"About 70 grams
The other hand, low cost, poor process of a few dollars of the compass, in the rotation compass, the pointer to swing around repeatedly after a stable point;
※ Built-in damping oil, better stability, more suitable for sports, rugged environment;
※ copper shell: the average thickness of 0.6 mm, durable;
※ pointer with luminous design, light absorption, clearly visible in the night;
※ glass mirror, better transparency, more wear-resistant;
※ compass back attached velvet, better adhesion, placed in a smooth plane, will not slip;
※ Compass scale clear, work well, shell plating 14K gold, highlight the grade, can be used as a gift to share.
"Instructions for use"
E S W N stands for SE
The arrow points in the north direction
Turn the compass so that the letter 'N' coincides with the arrow (point to the same), then the other letters on the compass corresponding to the direction of the actual geographical position
※ use in the horizontal state, in order to ensure as accurate as possible;
※ In order to avoid disorder of the magnetic needle, please keep a distance with the wire mesh and magnetic objects (such as high-voltage lines, generators, audio, magnets, etc.);
※ Do not beat or hand-beat compass, so as not to affect the measurement accuracy;
※ keep the shell and mirror smooth, do not use dirty cloth, hand to wipe;
※ When not in use put into the box, placed not near the ferromagnetic material, so as not to loss of magnetic.
Compass small knowledge:
Compass refers to the geography of the Antarctic is the magnetic North
Compass is used to determine the position of a simple instrument.Compass is the predecessor of the four ancient Chinese invention of Sinan. The main component is a free rotation on the shaft of the magnetic needle. Magnetic needle in the magnetic field to maintain In the tangential direction of the magnetic meridian, the north pole of the magnetic needle points to the geographic south pole, which can be used to identify the direction, and is commonly used in navigation, geodesy, travel and military affairs.
The invention of the compass is the working people in China, in the long-term practice of the object of magnetic cognition results.As a result of labor, people contact with magnetite, began to understand the magnetic properties of people first discovered the nature of the magnet iron. But also found the direction of the magnet.Through various experiments and research, and finally invented the compass can be practical.
'Compass direction of the principle of'
Earth is a large magnet, its geomagnetic south pole near the geographic north pole, geomagnetic north pole near the geographic south pole.
Compass in the earth's magnetic field by the role of magnetic force, so one end of the guide side of the north.
China's 'four great inventions' one of the compass, was transferred to Europe after the discovery of the nautical play an irreplaceable role, but historians of science clear, first answer 'compass why guide' problem is not the Chinese, but British scientist Gilbert .Then, China invented the compass after the compass theory of what kind of discussion? Gilbert's theory is timely reached China? The late Ming and early Qing Dynasty 'Western learning', but also on our compass theory Development of what impact? Shanghai Jiaotong University, Professor of History of Science and Philosophy of Science and Development from the beginning of 2003 to begin to study these basic or blank.
'China's compass theory is based on the theory of yin and yang of the five elements of the' induction '.' Guan Zengjian introduction, the middle of the 11th century when the great scientist Shen Kuo also compass on the incredible, his 'Mengxi Bi Tan' describes the compass of the artificial Magnetization method, the discovery of magnetic declination and compass erection method, but the guidelines for the compass but why there is no concept - 'the guide of the magnet ... ... Mo can be the original reason!' Subsequently, the scholar scholars from the yin and yang theory , Combined with the then people's understanding of the shape of the earth, put forward a variety of compass theory.For example, the late book in the Song Dynasty, "Guan's geography refers to Mongolia," first proposed the following logic:
'Iron is made of iron, iron metal, according to the five elements of Health grams that the Jinsheng water, and the North is a water, so the water is the son of the North. Iron produced in the magnet, the magnet is produced by the yang of gestation , The yang is a fire, located in the south, so the South is equivalent to the mother of magnetic needle so that the magnetic needle not only care for the mother, but also nostalgia for children, naturally we must point north and south.
Guanzeng Jian said that from the modern point of view of physics, 'Meng's theory' completely whimsical, but starting from the properties of things to explain their behavior in the history of Eastern and Western science are common practice.Chinese ancient theory of yin and yang, with yin and yang theory The interpretation of the compass guidelines and the principle of 'east-east' is, of course, a natural thing, especially since the theory suggests that the different faces of the magnet have different properties that determine the orientation of the needle, And further to associate the magnetic pole and the relationship between the magnetic needle point, so as to correctly understand the problem to find possible ways.
The compass principle of the Southern Song people still think that the meaning of the compass is that the yang is located around the phenomenon of magnetic declination, the argument based on more coordinate system to the geographical position of the ancient Chinese that is flat , The size is limited, so the surface must have a center, the center of the meridian is the only north-south direction.Southern Songren had three different and so that once the measurement is not in this north-south line, the compass point to the natural ' To the Ming Dynasty, it was fake Tongan Tang pointed out that the guide is the needle by the geodetic system, while the angle is determined by the celestial azimuth classification system determined that this statement 'reflects the traditional compass theory in the yin and yang induction Doctrine and the existence of magnetic declination in front of this contradiction shown by the distress'.
Ming Dynasty (AD 1573 ~ 1620), the missionaries came to China, bringing the Western compass theory, earth science and related scientific and technological knowledge.Under its influence, Chinese scholars began to explore the compass theory from a new perspective, in the process , The role of yin and yang of the five elements continue to play down the mechanical point of view of the increasing analysis, but Gilbert's theory of scientific theory in 1600 did not even Western academic unity, not to mention the East into the earth.Missionaries in 1658, The Jesuits of Belgium, the Southern Compass theory system, but he decided that the magnetic needle pointed to the Earth's geography north and south poles itself, the theory is still confined to the scope of ancient science, rather than Gilbert recognized the existence of the earth itself a magnet The theory of the South Huairen was far - reaching in China until the middle of the nineteenth Century, there are still scholars use it to explain the compass problem.At this point, the missionaries in China at the end of the Qing Dynasty began to introduce modern Western magnetism knowledge to China.
'The discovery of magnetic phenomena'
Our forefathers have accumulated a lot of knowledge in the pre - Qin period, and they often encounter magnets, ie magnets (mainly ferroferric oxide), which are well documented in the exploration of iron ore. "There are magnets in the mountains, under which there are gold and copper." Other ancient books such as "Shan Hai Jing" also has a similar record. Magnetite absorption characteristics have long been found, "At that time people called the 'magnetic' as 'Ci', they attract the magnet as a mother to attract their children to mothers.And that: 'Stone is the mother of iron, but there are two kinds of stone and non-compassion, loving stone to attract his children, unkind stone can not be attracted.' It is said that after the reunification of the Six Emperors, Xianyang, In a door is made of magnet, if someone wearing a helmet, hidden weapons, into the palace assassination, will be magnet door suction .This story tells us that the ancient working people have long mastered the knowledge of magnetism.
Before the Han Dynasty people to write the magnet 'Ci Shi', is the meaning of love stone.
Since the magnet can attract iron, then whether it can attract other metals? Our ancestors have done a lot of attempts to find the magnet not only can not attract gold, silver, copper and other metals, can not attract brick and the like. It has been recognized that magnet can only attract iron, but can not attract other items.
When the two magnets together close to each other, and sometimes attract each other, and sometimes mutually exclusive.Now people are aware of the magnet has two poles, one called the N pole, one called the S-polarities are mutually exclusive, the opposite sex extremely At that time people do not know this truth, but this phenomenon can still be aware of.
To the Western Han Dynasty, there is a large alchemist named Luan, he made use of this nature of the magnet two pieces of things, by adjusting the polarity of the two pieces of mutual position, sometimes the two pieces attract each other, sometimes mutually exclusive. Big call it 'fighting chess.' He put the novelty of the things dedicated to the Emperor, and on the spot demonstration .Han Wudi surprised, Long Xin Yue, actually sealed Luan great 'five Lee generals.' Luan large magnet Nature, produced a novelty stuff deceived the Emperor.
Earth is also a large magnet, its two poles are close to the geographical and geographic Arctic Antarctic place. So the Earth's surface of the magnet, can be free to rotate, it will be due to homogeneous repulsion of the magnet, the opposite sex to attract nature north and south. The ancients do not understand the truth, but these phenomena they are very clear.
'Compass ancestor - Secretary South'
The compass of the ancestor appeared in the Warring States period, it is made of natural magnets, looks like a spoon, round bottom, can be placed on a smooth 'site' and maintain balance, and free rotation.When it is stationary When the spoon handle will point to the south, the ancients called it 'Si Nan', then the book 'Han Fei Zi' in: 'Xian Wang Li Si to the end of the morning and evening' 'side of the morning and evening' is the Quartet, the meaning of orientation. Guiguzi "recorded in the application of the Secretary for South, Zheng people Caiyu Shi brought with the Secretary to ensure that the South is not lost.
Spring and Autumn Period, people have been able to hardness of 5 degrees to 7 degrees of jade and jade into a variety of shapes of the apparatus, it can also be only 5.5 degrees to 6.5 degrees of natural magnet made of Sinan. Eastern Han Dynasty Wang Chong in his The book "Lun Heng" in the shape and usage of Sinan made a clear record of Sinan is made of a single piece of natural magnets made of spoon type, spoon handle guide pole, and the spoon's center of gravity just fell to the bottom of the spoon The middle, the spoon placed in a smooth site, the site outside the inner circle, surrounded by a four-dimensional engraved with Ganzhi, synthesis of 24. This design is the ancients carefully observed a lot of nature-related magnetic phenomena, and accumulated a lot of knowledge and Experience, after a long period of research to complete .Snan is the emergence of people on the magnet refers to the practical application of polar recognition .Sinan also has many shortcomings, natural magnets are not easy to find, in processing easy to blow, heat loss. Of the magnetic comparison is weak, and it is very smooth contact with the site, otherwise it will rotate friction resistance is too large, and difficult to rotate, can not achieve the desired effect of the guide and the South has a certain size and weight, carrying very inconvenient, May be the long-term Division has not been widely used in the main reason.
Si Nan by the bronze plate and the magnetic spoon made of natural magnets, bronze plate engraved with twenty-four, set the magnetic spoon on the disk center circular surface, still, spoon tail pointing to the south.