Before the invention of the compass, ships were frequently lost in the big oceans and the consequences would be so dire. The Chinese invented the compass that solved the problem. The apparatus mainly consists of a free moving magnetic needle installed on a fixed axis. The geomagnetism makes the needle maintaining parallel to the meridian of the earth. The north pole of the needle points to the geographical South Pole, by using this property of the compass, we can know our direction of travel. This apparatus is widely used in navigation, surveying and the military. Basically, people use a magnetized steel needle with tiny grasses perforated, and then put it on a bowl of fresh water, the needle will float on the surface of the water. Thus people know the direction of sailing of their ships in ancient China. By making use of the geomagnetism, the compass was invented.
In pre-Qin time the Chinese have already obtained the knowledge of geomagnetism. People called the magnet as the "Kind Stone" which meant "a caring mother is so loved by her children". If a piece of stone that has a magnetic force, it is a kind stone. There were many tests done by ancient Chinese had proven that a magnet could only attract to steel, but it does not stick to other metals, wood and porcelain wares. At that time, the Chinese did not know the earth is actually a magnetic field, but they knew through many tests that a magnet has two poles (S and N), which the same poles of two magnets repel one another but different attract and stick together.
The first compass appeared during the Warring States Period, it was made of a piece of loadstone. Shaped like a spoon with a circular base, the magnet was placed on a flat and smooth surface. Of course the magnet piece can move very freely in a circular motion. However, this kind of compass has its disadvantages, loadstones that meet the requirements for making the apparatus are difficult to find and due to the intense heat during molding, the magnetic force in the loadstone will be reduced, thus the accuracy of the apparatus is questionable.
Later, the Chinese began to implement the artificial magnetization technique. This is to make a piece of steel becomes a magnet. They put the burned piece of steel in a position that is parallel to the earth's meridian, the molecules in the heated steel are very active, and so they will eventually position their direction according to the earth magnetic field. Then the steel is put in cool water, which makes the molecules fixed very quickly. The artificial magnetization technique is a great breakthrough in making compass. Another method is to magnetize the steel needle by friction with a piece of strong magnet.
As science and technology developed in ancient China, the technique in manufacturing compass has improved so much. The apparatus became an essential tool for sea voyages during the Yuan Dynasty. The compass is widely used all around the world today.
Another great invention of the Chinese is the gun powder. Known as "Blazing Medicine" in Chinese, the gun powder is made by three kinds of ancient folk medicine : saltpeter, sulfur and charcoal. Since the Qin Dynasty, people have been using saltpeter and sulfur to make drugs. The substances once exploded accidentally, the drug makers were astonishingly inspired, so they tested many times in order to carry out effective explosions. An outstanding technician in the Three Kingdom Period, Ma Jun, has made a kind a firecracker toy by packing the gun powder inside a piece of paper. It was the first true application of the gun powder.
During the latter years of the Tang Dynasty, the gun powder began to serve the military field. In wars, the soldiers used stone-shooting equipment to shoot out ignited gun powder packs. Later, gun powder was packed in sphere shape and tied up at the front end of an arrow, and then shot out. The gun powder balls were sometimes filled with poisonous substances, making the weapon more lethal. In the Song Dynasty, gun powder filled the bamboo barrel, a directional stick is stuck in the back of it. The stick ignites the barrel and makes it burning and shooting out. This device is the first rocket in the world. The Chinese guns were made according to the similar principle. The gun powder is the mother of modern firearms and weaponry.
The invention of paper making is a great contribution to the world's cultural development and international communication. In the Shang Dynasty (about 3,500 years before present), the Chinese had already have their own written characters, which were known as the "oracle bone" because the words were carved on animal's bones or tortoise's shell. During the Warring States Period, bamboo and wooden plates were instead of bones. However, bones, bamboo and wood were too heavy to carry. Hui Shi, a philosopher flourished in the Warring States Period had to hire five carriages to carry bamboo and wooden plates which were all his "books" when he went abroad to teach.
During the Western Han Dynasty (about 2,200 before present), the noble caste wrote on thin paper made of silk or cotton. It's easy to write and even excellent for painting on this kind of paper. However, it was extremely expensive, no civilian had the buying power to purchase.
In 105 AD, A high ranking official in the Eastern Han Dynasty, Cai Lun combined the knowledge of paper making in the past, invented a kind of cheap plant fiber paper, which was made of cortex, broken fishnets and cloths. Since then, paper has been popular among common people.
The paper making technique was introduced to Korea and Japan in the 7th century and the Arab World in the 8th. In the 12th century, the Europeans began to adopt this technique.
This is also a great invention for the world. During the Sui Dynasty, printing is accomplished by mean of a knife cut laterally reversed characters on wooden boards, paint ink on it, and then print the characters on the paper. However, the wooden board can be used once, because the boards are specially made for the printing of the book. Therefore, to print a book was a very painstaking task at that time and to print a book of different content, another batch of boards should be made.
The difficulty was solved in the 11th century. A lettering worker, Bi Sheng spent 40 years to make type of the Chinese characters. He used lime cement as material, molded into square columns, carved a laterally reversed Chinese character on the bottom of one column, and then baked to hard in a furnace. These columns could be arranged according to the contents of the book to be printed, so the type could be reused unlimited times. This technique is the rudiment of modern printing.
Wang Zheng, a mechanist flourished in the Yuan Dynasty invented and developed the wooden type and typesetting method respectively. A few years later, he invented the metal type which greatly improved the printing quality. The technique was introduced to Japan during the Tang Dynasty and to Germany in the 15th century. The printing technology has helped the cultural and scientific development in Europe since the Renaissance.