Compass is an instrument that uses the earth's magnetic field to indicate the direction, and it is also one of the earliest tools used for navigation and positioning.
According to historical records, compasses were used in ancient China, which first appeared in the Han Dynasty (206 BC-220 AD) in ancient China. At that time, the compass was a magnet made of magnetic mineral magnetite. The direction can be judged by soaking the magnet in water to make it float, and then observing its direction.
China's compass technology gradually developed and improved in ancient times, and was introduced to other parts of the world in the Tang Dynasty (6 18-907). The invention and application of the compass has played an important role in promoting the development of navigation, military affairs and exploration, and has also had a far-reaching impact on human geographical cognition and traffic development.
1, compass
Compass is an instrument that uses the earth's magnetic field to indicate the direction, which is used to determine the east, west, north and south of the geographical direction. A compass usually consists of a magnetic needle and a scale. The magnetic needle is made of magnetic substance, which is magnetic and can rotate freely. The magnetic needle will be influenced by the earth's magnetic field and point to the north-south direction of the earth's magnetic field.
The scale of a compass is usually a disk or a disk, on which the compass bearing and angle scale are marked. The main directions (including north, east, south, west and their combinations) include a 360-degree dial and a 16 dial.
When using the compass, keep the compass horizontal for a moment, let the magnetic needle rotate freely, and make it stable in one direction. Then by observing the direction pointed by the magnetic needle, we can determine the direction, such as east, west, north and south.
Compass is widely used in navigation, exploration, military and outdoor activities, providing people with direction guidance and positioning services. Modern compasses have also been improved in technology, including electronic compasses, magnetometers and other high-precision navigation instruments.
2. Four great inventions.
The four great inventions refer to the four important inventions in ancient China, which have had a far-reaching impact on human civilization and scientific and technological progress.
Papermaking is one of the earliest important inventions in ancient China. Around A.D. 105, Cai Lun of Han Dynasty improved the ancient pulping method and invented papermaking.
Printing was invented by Bi Sheng in the Northern Song Dynasty. Bi Sheng made movable type into wood or stone, pieced them together and printed them, which greatly improved the speed and efficiency of making books.
Gunpowder is an explosive mixture invented in ancient China and used in military and fireworks production. Wen Tianxiang and others in Song Dynasty invented gunpowder around 10 century. The invention of gunpowder greatly changed the way of war, promoted the development of firearms and brought great historical and military influence.
The South Needle was a navigation tool in early ancient China, which was used to determine the direction. Since ancient times, China people have noticed the directional characteristics of magnets and applied them to practical navigation.