Shen Kuo's information

Shen Kuo (A.D. 103 1- 1095), born in Qiantang, Hangzhou (now Hangzhou, Zhejiang), was a scientist and politician in the Northern Song Dynasty. Injong Jiayou was a scholar for eight years (1063). Zong Shen participated in Wang Anshi's political reform. In the fifth year of Xining (1072), he was promoted to supervisor of Tianbu, and went to Zhejiang to inspect water conservancy and officers the following year. In the eighth year of Xining, he sent envoys to Liao country to refute Liao country's claim to land. The following year, he served as a bachelor of Hanlin, and made the third secretary right, rectifying Shaanxi salt policy. Later, Yanzhou (now Yan 'an, Shaanxi) was famous for strengthening its defense against Xixia. In the fifth year of Yuanfeng (1082), Song Jun was defeated by Xixia in the battle of Yongle City and was demoted. In his later years, he wrote Meng Qian Bi Tan according to his own life experience.

Shen Kuo's scientific achievements are manifold. He devoted himself to astronomy and advocated a new calendar similar to today's solar calendar. In physics, he recorded the principle of compass and various production methods; The existence of magnetic declination was discovered more than 400 years before Europe. The principle of concave mirror imaging is expounded. The law of * * * vibration is also studied. In mathematics, he founded "gap product" (second-order arithmetic progression summation method) and "meeting circle" (knowing the diameter of the circle and the height of the bow, and finding the chord length and arc length of the bow). In geology, he studied the formation of alluvial plain and water erosion, and put forward the name of oil for the first time. In medicine, there are many records about effective prescriptions and many medical works. In addition, he also recorded the scientific development and production technology at that time, such as movable type printing and metal smelting method invented by Bi Sheng.

Biography of Shen Kuo

In the Northern Song Dynasty in China, there was a very knowledgeable and outstanding scientist. He is Shen Kuo, one of the most outstanding scientists in the history of China. He is proficient in astronomy, mathematics, physics, chemistry, biology, geography, agriculture and medicine; He is also an outstanding engineer, excellent strategist, diplomat and politician. At the same time, he is knowledgeable, good at writing and proficient in other people's calendars, music, medicine, divination and so on. Meng Qian Bi Tan, written in his later years, recorded in detail the outstanding contributions of working people in science and technology and their own research results, reflecting the brilliant achievements of natural science in ancient China, especially in the Northern Song Dynasty. Meng Qian's pen talk is not only an academic treasure house in ancient China, but also occupies an important position in the history of world culture. Known as "the coordinates in the history of science in China".

Shen Kuo was born in Qiantang, Zhejiang (now Hangzhou, Zhejiang) to a bureaucratic family. His father Shen Zhou worked as a local official in Quanzhou, Kaifeng and Jiangning. Mother Xu Shi is a well-educated woman. Shen Kuo was born in the ninth year of Tiansheng in Song Renzong (A.D. 103 1). He studied hard since he was a child. Under the guidance of his mother, he finished reading at home at the age of fourteen. Later, he followed his father to Quanzhou, Fujian, Runzhou, Jiangsu (now Zhenjiang), Jianzhou, Sichuan (now Jianyang) and Kaifeng, the capital of China. He had the opportunity to get in touch with the society, understand the life and production of the people at that time, increase his knowledge and show his superhuman intelligence. At the age of twenty-four, he started his career. He was the chief book of Shuyang County (now Jiangsu Province) in Haizhou, and then the county magistrate of Donghai (now Jiangsu Province), Ningguo (now Anhui Province) and Wanqiu (now Huaiyang County, Henan Province). At the age of 33, he was appointed as the governor of Yangzhou to join the army and was in charge of criminal trial. Three years later, he was recommended to Zhao Wen Concert Hall in Shi Jing to edit and proofread books. Here he began to study astronomical calendars. Song Shenzong Xining five years (A.D. 1072), who was also the supervisor of astronomical phenomena, was responsible for observing astronomical phenomena and calculating almanac. Then, Shen Kuo served as the review of the history museum, and in the sixth year of Xining (A.D. 1073), he became the general manager of Jixian College. Due to the convenience of his position, he has the opportunity to read more royal books and enrich his knowledge. 1075 was sent to Liao for border negotiations, and the following year he served as a bachelor of Hanlin and was appointed as the third secretary.

In the second year of Xining in Song Shenzong (A.D. 1069), Wang Anshi, a representative of the landlord class reformists, was appointed as prime minister and began a large-scale political reform movement. Shen Kuo actively participated in the political reform movement and was trusted and valued by Wang Anshi. He has served as the highest official in charge of state finance, three secretaries and many other important positions. In the ninth year of Xining (AD 1076), Wang Anshi's political reform failed. Shen Kuo was falsely demoted as an official and renamed Xuanzhou (now Xuancheng, Anhui). Three years later, in order to resist Xixia, he changed to Yanzhou (now Yan 'an, Shaanxi) and served as the envoy of Yan 'an Road. Yuan Feng was promoted to a bachelor's degree in Longtuge in the fifth year (AD 1082) for his meritorious service in guarding the frontier. However, he was soon framed and demoted to be the deputy ambassador of Zhou Jun (now Xunxian County, Hubei Province). In the second year of Zhe Zongyuan (A.D. 1087), Shen Kuo spent 12 years compiling the Map of Counties and Counties in the World, which was submitted in Bianjing by special permission. The following year, he settled in Meng Xi Park in Runzhou (now the eastern suburb of Zhenjiang, Jiangsu) to spend his old age.

In his later years, Shen Kuo carefully summed up his life experience and scientific activities in Meng Xi Park, and wrote famous scientific masterpieces such as Meng Qian's Pen Talk and Forgetting His ambition. Song Zhe died in the second year of Zong Shaosheng (AD 1095). He wrote dozens of books in his life, but only a few comprehensive collections, such as Changxing Collection and Prescription Science, have been circulated so far. Meng Qian Bi Tan is the coordinate of Chinese science history and the summary of Shen Kuo's social science activities all his life. Its content is extremely rich, including more than 600 articles on astronomy, calendar, mathematics, physics, chemistry, biology, geography, geology, medicine, literature, history, archaeology, music and art, among which 200 articles belong to science and technology, recording many of his inventions, discoveries and opinions. Shen Kuo is a scientific generalist.

Water control in Shen Kuo

Shen Kuo attaches great importance to developing agricultural production and building water conservancy projects. As early as his youth, when he was the chief accountant of Shuyang County, he presided over water control projects, organized tens of thousands of migrant workers and built canals and weirs, which not only relieved the flood threat of local people, but also reclaimed 7,000 hectares of fertile land and changed the face of Shuyang. At that time, he was only 24 years old. When he was appointed as the county magistrate of Ningguo, he actively advocated and presided over the construction of a large-scale and solid Wanchunwei in Wuhu, Anhui Province, and opened up 1270 hectares of fertile land that could be drained and irrigated to ensure a bumper harvest in drought and flood. At the same time, he also wrote five books on polder fields and Wan Chunwei's book.

In the fifth year of Xining (A.D. 1072), Shen Kuo presided over the Bianhe water conservancy construction. In order to harness the Bianhe River, Shen Kuo personally measured the topography of the Bianhe River downstream from Kaifeng to the bank of Huaihe River in Sizhou for 840 miles. He used the method of "building a weir by layers" to calculate that the terrain height difference between Kaifeng and Sizhou was 19 feet, 4 feet, 8 inches and 6 minutes respectively. In this topographic survey method, the Bianhe River is divided into many sections, which are built into stepped dikes, and water is poured into them. Then, the water surface of each section is measured section by section, and the difference of each section is accumulated, and the sum is the "terrain reality" between Kaifeng and Sizhou. This is a pioneering work in the history of world water conservancy. In just four or five years, more than 17,000 hectares of land have been silted up by water diversion, with remarkable achievements. When calculating the terrain height, the unit is accurate to one inch, which shows that Shen Kuo's academic attitude is extremely serious.

An outstanding astronomer

Shen Kuo is also an outstanding astronomer. In the fifth year of Xining (A.D. 1072), when he was in charge of Bianhe construction in Shen Kuo, Shen Kuo was also in charge of leading the Tianjian Supervision Department. During his tenure, he successively dismissed six uneducated old calendar officials, regardless of their origins, and recommended Wei Pu, a Huainan native who was proficient in astronomical calendar calculation and was born in a civilian, to enter the Tianjian Supervision Department to preside over the important work of revising the new calendar. Shen Kuo and Wei Puzhi took a serious attitude and were very dissatisfied with the calendar revision method that the old calendar officials relied on calculus. They advocate starting with observing the astronomical phenomena and taking the measured results as the basis for revising the calendar. Therefore, Shen Kuo first studied and reformed the old astronomical observation instruments, such as armillary sphere, floating leak and shadow table.

The armillary sphere is an instrument for measuring the orientation of celestial bodies. After the development and evolution of the past dynasties, by the Song Dynasty, the structure of the armillary sphere had become very complicated, three times, intertwined and inconvenient to use. Therefore, Shen Kuo reformed the armillary sphere for many times. On the one hand, he canceled the small white ring, simplified the instruments and division of labor, and then linked the relationship between them with mathematical tools ("the moon ring is omitted, and the difference between the moon and the moon is only a step based on the calendar"); On the other hand, it is suggested to change the position of some rings so that they do not block the line of sight. These reform measures in Shen Kuo have opened up a new road for the development of musical instruments. Later, in the 13th year of Zhiyuan (A.D. 1276), Guo Shoujing of Yuan Dynasty created a new astronomical instrument-Jane Instrument, which was produced on this basis.

The clepsydra is an ancient instrument for measuring time. It is composed of several water containers in the form of steps, and the lower side of each container has holes, which drip from the next container in turn. There is no hole in the bottom container, but there is an "arrow" engraved with the time scale. As the dripping water level rises, the "arrow" slowly floats, and the time can be read from the exposed scale. Shen Kuo also reformed leaky cauldron. He changed the copper leaky pipe of the curved barrel into a straight-necked jade mouth and moved it to the lower part of the pot body. This makes the running water smoother, and the spout is much stronger and more durable.

In addition, Shen Kuo has formulated the standard for measuring the sun's shadow and improved the method for measuring the shadow.

Shen Kuo introduced his research achievements in three papers: On the Hunyi, On the Floating Leak and On the Landscape, elaborated the principle of instrument transformation in detail, and expounded his own astronomical views, which played an important role in the history of astronomy in China.

A series of innovative activities of Shen Kuo and Wei Pu were attacked and framed by conservative forces. Under the resolute struggle of Shen Kuo and Wei Pu, the revised Fengyuan Calendar presided over by Wei Pu was finally completed and promulgated in the eighth year of JaeHee Ning (A.D. 1075). However, due to the obstruction and destruction of conservative forces, the relatively advanced abundant calendar was abolished after only 18 years. However, Shen Kuo didn't lose heart because of this. In his later years, he further put forward the idea of replacing the original calendar with the "Twelve-qi Calendar". The original calendars in China were all based on the combination of yin and yang, but the "twelve-qi calendar" was a pure solar calendar. The year is divided into four seasons, and each season is divided into three months: Meng, Zhong and Ji, and the month is determined according to the solar terms. Beginning of spring's day is 1 month 1 day, and the day of fright is February 1 day, and so on. Thirty-one days for the big moon and thirty days for the small moon. The big moon and the small moon appear alternately. Even if there is a situation that "two little moons are combined into one", it is only once a year. There are "two small pictures", with 365 days in a year; No, 366 days a year. In this way, the days of the year are very neat, there is no need to set up a leap month, and the four seasons are fixed dates. As for the moon's profit and loss, it has nothing to do with the season when the cold comes and goes, as long as you indicate "new moon" and "hope" in the almanac. The calendar designed by Shen Kuo is scientific, which is not only in line with the reality of celestial bodies, but also conducive to the arrangement of agricultural activities. He foresaw that his ideas would be attacked and scolded by diehard conservatives, and he tried his best to obstruct them, but he firmly believed that "different times will be useful to speakers." Sure enough, nearly 800 years later, the basic principles of the calendar promulgated by the great peasant revolutionary regime, the Taiping Heavenly Kingdom, were completely consistent with Shen Kuo's Twelve Qi Calendars. The Gregorian calendar adopted by countries all over the world, that is, the solar calendar, is actually not as reasonable as the "twelve-year calendar" in Shen Kuo.

Physicist+chemist+mathematician

Shen Kuo's achievements in physics research are also extremely rich and precious. The opinions and achievements recorded in Meng Qian's Bi Tan involve mechanics, optics, magnetism, acoustics and other fields. In particular, he has made outstanding achievements in magnetic research. Shen Kuo explicitly talked about the deflection angle of the magnetic needle for the first time in Meng Qian Bi Tan. In terms of optics, Shen Kuo made a popular and vivid exposition on pinhole imaging, concave mirror imaging, and the zoom-in and zoom-out functions of concave-convex mirror through personal observation experiments. He also made some scientific explanations for the light transmission reason of the so-called "transparent mirror" (a bronze mirror that can see the front pattern on the back) handed down from ancient China, which promoted the later research on "transparent mirror". In addition, Shen Kuo also did experiments on the piano to study the phenomenon of acoustic vibration.

In chemistry, Shen Kuo has also made some achievements. When I was in Yanzhou, I studied Lu Yan's oil reserves and uses. Taking advantage of the fact that oil is not easy to burn completely to produce carbon black, he pioneered the process of making cigarette ink with petroleum carbon black instead of pine carbon black. He has noticed that oil resources are abundant, "born in infinity" and predicted that "this thing will be popular in the world", which has been verified today. In addition, the name "petroleum" was first used in "Shenkuo", which is much more appropriate than the previous names such as stone paint, stone grease water, fierce fire oil, kerosene, naphtha and stone candle. In Meng Qian Bitan's "Taiyin Xuan Jing" (gypsum crystal), Shen Kuo distinguished several kinds of crystals from morphology, deliquescence, cleavage and heating dehydration, and pointed out that although they have the same name, they are not the same thing. He also talked about examples of metal transformation, such as the physical phenomenon of changing iron into copper with copper sulfate solution. These means of identifying substances described by him show that people's research on substances at that time has broken through the observation of simple surface phenomena and began to explore the internal structure of substances.

Shen Kuo also has excellent research in mathematics. Starting from the actual calculation needs, he founded "gap product technology" and "convergence technology". Shen Kuo put forward a correct method to find the total stack number of jars and chess pieces by studying the volumes of jars and chess pieces with gaps, that is, the "gap product method", that is, the second-order arithmetic progression summation method. Shen Kuo's research has developed the arithmetic progression problem since Nine Chapters of Arithmetic, and opened up the research direction of higher-order arithmetic progression in the history of ancient mathematics in China. In addition, Shen Kuo also studied the relationship among arc, chord and vector in a circular bow from the calculation of field, and put forward the first simple and practical approximate formula for calculating arc length from the length of chord and vector in the history of mathematics in China, which is called "the skill of meeting circles". The establishment of this method not only promotes the development of plane geometry, but also plays an important role in astronomical calculation and makes an important contribution to the development of ball science in China.

Geographer+medical scientist

Shen Kuo also made many outstanding conclusions in geosciences, which reflected that China's geosciences reached the advanced level at that time. He correctly discussed the reasons for the formation of the North China Plain: according to the banded distribution of snail shells and oval gravel between the cliffs of Taihang Mountain in Hebei Province, it was inferred that this area was a seashore in ancient times, and the North China Plain was formed by sediment carried by rivers such as the Yellow River, Zhangshui River, Hutuo River and Sanggan River. During his inspection in eastern Zhejiang, he observed the geomorphological features of Yandang Mountain peak, analyzed its causes, and clearly pointed out that it was the result of water erosion. He also made a similar explanation based on the geomorphological features of the loess area in northwest China. He also observed and studied similar bamboo shoots and various fossils such as peach pit, reed root, pine tree, fish and crab excavated from underground, clearly pointed out that they were the remains of ancient animals and plants, and inferred the ancient natural environment from the fossils. All these show Shen Kuo's valuable materialism. In Europe, it was not until the Renaissance that the Italian Leonardo da Vinci began to discuss the nature of fossils, more than 400 years later than Shen Kuo. When Shen Kuo visited the border of Hebei Province, he made a three-dimensional geographical model of the mountains, roads and terrain he visited on the board. This practice was quickly extended to the border States. In the ninth year of Xining (A.D. 1076), Shen Kuo was ordered to compile the map of counties in the world. He consulted a large number of files and books, and after nearly 20 years of unremitting efforts, he finally completed the masterpiece "Shouling Map" in the history of cartography in China. This is a large atlas, with 20 maps, including a large map, one foot high and two feet wide; Small picture; Eighteen maps for each road (according to the administrative divisions at that time, the whole country was divided into eighteen roads). The scale and detail of the map are rare before. In painting, Shen Kuo put forward nine methods, such as grading, quasi-viewing, mutual integration, side inspection, competition, square inclination and straight pedaling, which are generally consistent with Pei Xiu's famous six-body painting method in the Western Jin Dynasty. He also subdivided all directions into twenty-four directions, which further improved the accuracy of the map and made important contributions to ancient cartography in China.

Shen Kuo is also proficient in medicine and biology. He was interested in medicine since he was a child and devoted himself to medical research. He collected many prescriptions and cured many critically ill patients. At the same time, his knowledge of medicinal botany is also extensive, and he can actually find out, distinguish authenticity and correct mistakes in ancient books. He once put forward a new theory of "five difficulties"; Shen Kuo's medical works include Prescription, etc. The existing Su Shen Liang Fang was made by later generations attaching Su Shi's Miscellaneous Treatise on Medicine to the Prescription.

Materialist.

Shen Kuo has a simple materialistic thought and a viewpoint of development and change. He believes that "the change of heaven and earth, the violence of cold and summer, the drought of floods and the locusts of moths all have laws", and points out that "the principle of going with the sun and going against the yin has its own origin, following nature and coming unexpectedly." That is to say, the changes of things in nature are regular, and these laws exist objectively, regardless of human will, and these laws also exist objectively, regardless of human will. He also believes that there are normal and abnormal changes in the laws of things, and we can't stick to fixed rules. It was these correct ideas and viewpoints that prompted him to make great achievements in science and technology at that time. Shen Kuo once put forward the view that known knowledge is limited and human knowledge is infinite, which has great influence on the development of science.

The ideological tendency of materialism is also manifested in Shen Kuo's attaching great importance to the practical experience and inventions of the working people, and constantly drawing wisdom and strength from the working people at that time. He once said: "As for the technical equipment, the size, black, yellow and reddish can all be made by saints! People who work a lot, a group of teachers and people in the fields are unpredictable. " In order to explore medical knowledge, he "asked to see everywhere he went, whether he was a doctor, a stranger, a villain, or even a scholar-bureaucrat's house or a hermit in the mountains." In Meng Qian Bi Tan, he recorded many outstanding contributions of the working people in the Song Dynasty in science and technology, which is admirable. For example, movable type printing invented by Buyibi (the last day+the second day), the architectural achievements of folk craftsmen Yu Hao and carpenters, the advanced method of closing the dragon and blocking the mouth created by He Gong Gao Chao, the deeds of civilian astronomer Wei Pu Li Xiu, and the valuable experience gained by many unsung heroes in the production struggle such as steelmaking in Hebei and tea planting in Fujian, etc. It is precisely because of Shen Kuo's detailed account that the achievements of many working people who have made contributions have been preserved and passed down.

The tendency of materialism determines that Shen Kuo's description of natural phenomena and scientific and technological achievements is scientific. His observation and description of things are very detailed, specific and accurate, and there is no bad habit of ordinary literati exaggerating in feudal times. So through his account, we can clearly judge the production technology and natural science level he reached at that time. For example, Shen Kuo's records of lightning, mirage, tornado, earthquake, meteorite and other natural phenomena are very detailed, appropriate and vivid, making people feel as if they were there.

Shen Kuo can study objective things from the viewpoint of development and change, and draw correct conclusions. When discussing many problems about mathematics, meteorology and medicine, he repeatedly stressed the need to adapt to local conditions and adapt to the times. For example, February and August in ancient times were the season for picking herbs, but Shen Kuo pointed out that the growth of medicinal materials was influenced by natural conditions and cultivation conditions, and there were different requirements for picking herbs, such as taking roots, leaves, buds, flowers and fruits. Therefore, it is necessary to choose the time of drug collection according to different situations, and it is not possible to "fix the month" rigidly. Shen Kuo's point of view is very reasonable.

Shen Kuo didn't just observe some superficial natural phenomena. He also tried to explore its scientific truth and put forward an explanation of the law of development and change of things. The explanations of many problems, such as the formation reasons of the peaks of Yandang Mountain and North China Plain, the location of Twenty-eight Hostels and the formation of fossils, are in line with modern scientific principles. In order to find out the truth of Yang Ai (concave mirror)' s imaging, he observed the shadows of birds in the air, compared the imaging differences by himself, and finally made a more correct explanation. These are the important reasons for his success in science.

Proficient in polite language and martial arts

Shen Kuo, who is both civil and military, not only made brilliant achievements in science, but also made important contributions to defending the territory of the Northern Song Dynasty. During the Northern Song Dynasty, class contradictions and ethnic contradictions were very sharp. The aristocratic rulers of Liao and Xixia often invaded the Central Plains and plundered the population and livestock, which brought great damage to the social economy. Shen Kuo is firmly on the side of the hawk. Zaixi (AD 1074) served as the governor of Hebei West Road and the chief inspector of military equipment during the seven years of Ning. He studied the art of war, seriously studied military issues such as city defense, array law, personnel vehicles, weapons, strategy and tactics, and compiled military works such as the Treaty of Repairing the City of France and the Array Law of Frontier States, and successfully applied some advanced science and technology to military science. At the same time, Shen Kuo has also made in-depth research on the manufacture of crossbow armor, knives, guns and other weapons, which has made certain contributions to improving the quality of weapons and equipment.

Medical source database: Shen Kuo (103 1- 1095), a scientist and physician in Song Dynasty. In the word, Qiantang (now Hangzhou, Zhejiang) was born. In the last year of Jiayou (1063). From officials to Hanlin bachelor, they have a wide range of knowledge. His masterpiece Meng Qian Bi Tan involves various disciplines, including astronomy, calendar, art of war, music, divination, physics and so on. This book mentions important inventions in ancient China, such as compass device, movable type printing, petroleum smelting, etc. In medicine, we have tasted Liang Fang (called Liang Fang) in Shencun, and Meng Xi's nasal sputum and nasal sputum, all of which are involved, such as Qiu Shi's preparation, the morphology, compatibility, pharmacology, preparation, collection and growth environment of 44 drugs. His Prescription was merged with Su Shi's Miscellaneous Notes on Medicine to form Su Shen Liang Fang, which has been published in many versions.

Brief introduction of Meng Xi's written speech

Written by Shen Kuo in the Northern Song Dynasty. This is a literary genre of notes about history, literature, art, science, etc. It is named after it was written in Meng Xi Park in Runzhou (now Zhenjiang, Jiangsu).

Meng Qian Bi Tan is a note novel by Shen Kuo in Song Dynasty. Written in 1086 ~ 1093, it contains what Shen Kuo saw, heard and thought all his life.

The existing Meng Qian Bi Tan has 26 volumes, which are divided into 17 categories ***609 articles: stories, dialectics, music, images, personnel, public affairs, intellectual power, literature and art, calligraphy and painting, skills, instrumental techniques, magic, wonders, fallacies, jokes, magazines and medicine. It covers astronomy, mathematics, geography, geology, physics, biology, medicine and pharmacy, military, literature, history, archaeology and music. Meng Qian Bi Tan is an important document and encyclopedic work in the history of science and technology in China.

In mathematics, he pioneered "gap product" and "pi". Astronomy points out that Polaris is not at the celestial pole; It is concluded that the winter solstice is long and the summer solstice is short. Astronomical instruments have also been improved. Boldly innovate in the calendar and put forward "twelve calendars in one place". In geography, water erosion is used to explain the causes of strange landforms. Recording magnetic declination, concave mirror imaging experiment and acoustic vibration experiment in physics. The book also describes some important scientific and technological achievements at that time, such as compass, movable type printing, copper smelting, steelmaking, petroleum and so on. Among them, the word "oil" was first put forward in the book and is still in use today.

In his later years, Shen Kuo wrote 26 volumes of Meng Qian's Bi Tan, and 3 volumes of Supplementary Bi Tan and Continued Bi Tan. * * * 609 articles, covering astronomy, mathematics, physics, chemistry, geoscience, biology, metallurgy, machinery, architecture, paper technology and other aspects. This is an important work in the history of China's science. Many scientific achievements recorded in Meng Qian Bi Tan reached the highest level in the world at that time. Needham, a famous British expert on the history of science, called Meng Qian's pen talk "the coordinate of the history of Chinese science".

The contents related to physics in Meng Qian Bi Tan mainly include acoustics, optics and magnetism, especially magnetism.

Shen Kuo left the earliest compass record in the history in Mengqianbitan. He recorded in the twenty-fourth volume "Magazine One": "Fangjia can be guided by a magnet grinding needle, but it is often eastward, not completely southward." This is the earliest magnetic declination record in the world. It was not until A.D. 1492 that Columbus discovered the geomagnetic declination when he first sailed to America, which was 400 years later than Shen Kuo's discovery. Shen Kuo also recorded in the third volume of Meng Qian's Notes on Essentials: "If you use a magnet to grind the needle, it will always be sharp in the middle, pointing to the north who is afraid of the stone." Shen Kuo not only recorded the making method of the compass, but also summarized four ways to place the compass through experimental research: put the magnetic needle horizontally on the wick, put it on the bowl edge or nail, and hang it with silk thread. Finally, Shen Kuo pointed out that hanging the magnetic needle with silk thread is the best method.

In optics, the knowledge recorded in Meng Qian Bi Tan is also extremely rich. On the basis of predecessors, Shen Kuo had a deeper understanding of the linear propagation of light. Explain the characteristics of light propagation along a straight line. He made a small hole in the paper window, so that the shadows of birds and towers outside the window could be imaged on the paper screen indoors for experiments. According to the experimental results, he vividly pointed out the linear relationship among objects, holes and images. In addition, Shen Kuo also used the principle of straight-line propagation of light to vividly explain the changing law of the moon phase and the cause of the solar eclipse. In Meng Qian Bi Tan, Shen Kuo also made a popular and vivid exposition on the imaging of concave mirror and the zoom-in and zoom-out function of concave-convex mirror. He also made some scientific explanations for the light transmission reason of the so-called "light transmission mirror" handed down from ancient China, which promoted the later study of "light transmission mirror".

In acoustics, Shen Kuo carefully designed an acoustic vibration experiment in Mengqianbitan. He cut a paper man and fixed it on a string. When a string with a simple integer ratio is played, it vibrates and makes the paper man jump, while when playing other strings, the paper man does not move. Shen Kuo called this phenomenon "the answer". It is Shen Kuo's initiative to show the * * * vibration in this way. In the west, it was not until the15th century that Italians began to do vibration experiments. Up to now, in the physics class of middle schools in some countries and regions, teachers have also used this method to demonstrate the vibration phenomenon for students.

Song Dynasty is one of the most brilliant periods of ancient mathematics in China. There are 10 articles on mathematics in Shen Kuo's famous work "On Meng Xi, a great scientist in the Northern Song Dynasty". The content is wide and deep, and it can be called the treasure of ancient mathematics in China.

Shen Kuo's most important mathematical exposition is gap product and circle. Gap product opened up the research field of higher-order arithmetic progression summation in the history of mathematics in China, and the research on higher-order arithmetic progression began in Shen Kuo.

The so-called "gap product" refers to the accumulation body with gaps, such as jars and chess pieces piled up in hotels. This accumulation is like an upside-down bucket, much like a truncated rectangular cone (straw boy). However, the edge of notch product is uneven and there is a notch in the middle, so Chu Tong's volume formula cannot be copied. After thinking, Shen Kuo found the correct calculation method. He took the piled jars as an example to illustrate this problem: the top floor was set with two jars vertically and horizontally, and the bottom floor was set with two jars vertically and horizontally 12, and the vertical and horizontal difference between two adjacent floors was 1 jar. Obviously, this pile of cans has *** 1 1 layer; The volume of each jar may be set to 1, and the total volume is 3784/6, and the total number of jars should be the same. Obviously, the number of cans should not be non-integer. What's the problem? Shen Kuo proposed adding a term "(lower width-upper width) × height /6" to the size of straw boy, which is 1 10/6, and the actual number of pots should be (3784+ 1 10)/6 = 649. This added item is only a volume correction item. Here, on the basis of the volume formula, Shen Kuo changed the cumulative number of discontinuous individuals (summation of series) into a continuous integer to solve, which shows his idea of using a continuous model to solve discrete problems.

Roundness is a practical approximate formula of the sagittal relationship of a circle. The main idea is to use straight lines instead of curves locally. Shen Kuo further applied the approximate formula of arc field area in Nine Chapters Arithmetic to find the arc length, which is the rounding formula. Although Shen Kuo's formula is approximate, it can be proved that the relative error is less than 2% when the central angle is less than 45, so this formula has strong practicability. This is an important proof of Liu Hui's thought of secant replacing arc with chord (the edge of regular polygon), which has important theoretical significance. Later, Guo Shoujing and Wang Xun applied rounding technique in calendar calculation.

In "Meng Qian Bi Tan", Shen Kuo also calculated the possible chess number of Go as 336 1 by combinatorial mathematics, and put forward a method to express the large number of 336 1 by the concept of order of magnitude. In his book, Shen Kuo also recorded some operational ideas, such as guiding the surging Bianshui to the ruins of the ancient city to rescue the collapse of the river bank, digging the road to repair the palace into a river, taking soil and transporting soil, and finally filling the river with construction waste. Shen Kuo's understanding of the essence of logarithm is also profound, pointing out: "Everything has a definite shape, and the shape has a true number." Obviously, he denied the mystery of numbers and affirmed the relationship between numbers and things. He also pointed out: "However, arithmetic does not suffer because of learning more. Use it when you see simplicity, and change it when you see complexity. It is also for general skills. "