Shen Kuo (1031-1095), a native of Qiantang County, Hangzhou, Zhejiang Province, was a politician and scientist in the Northern Song Dynasty.
Shen Kuo was born into an official family and traveled around with his father in his childhood. In the eighth year of Jiayou (1063), he was a scholar, and was named Yangzhou secretariat to join the army. In Song Shenzong, he participated in the Xining political reform and was highly valued by Wang Anshi. He has served as Prince Zhongyun, torture room, supervisor of the Ministry of Heaven, review of the history museum and three ambassadors.
In the third year of Yuanfeng (1080), he started his career in Yanzhou, served as a road show ambassador, and was stationed in the border to fight against Xixia. Later, he was demoted for participating in the battle of Yongle City. In his later years, he moved to Runzhou (now Zhenjiang, Jiangsu) and lived in seclusion in Meng Xi Park. Born two years less (1095), died of illness at the age of 65.
Shen Kuo devoted himself to scientific research all his life, and had profound attainments and outstanding achievements in many disciplines. He is known as "the most outstanding figure in the whole history of science in China". His masterpiece Meng Qian Bi Tan is rich in content and a great achievement of predecessors. It plays an important role in the world cultural history and is called "a milestone in the history of science in China".
Shen Kuo's achievements:
1, gap product
Notched product refers to how to calculate the superposition product. On the basis of volume formula, Shen Kuo solved the cumulative number of discontinuous individuals by analogy and induction, and converted it into a continuous integer value to solve it. He has the idea of using continuous models to solve discrete problems.
In the history of Chinese mathematics, the problem of arithmetic progression summation, which has been stagnant since the Southern and Northern Dynasties, has developed and advanced to a new stage of higher-order arithmetic progression summation, which initiated the study of China's superposition technique.
2. Rounding technology
In fact, the technique of knowing the circle refers to the method of finding the arc from the string. Its main idea is to replace the curve with a straight line locally, and give a practical approximate formula of the sagittal relationship of the circle.
In the history of Chinese mathematics, Shen Kuo was the first to find the approximate value of solitary length with chords and vectors. 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.
3. Attraction
Shen Kuo recorded the method of artificial magnetization, and made an experiment with an artificial magnetization needle to deeply study the compass. Shen Kuo compared four installation methods of compass: water float method, bowl edge method, nail method and hanging wire method, and pointed out that hanging wire method was the best, and made corresponding analysis.
Magnetic declination refers to the angle between geomagnetic meridian and geographical meridian at any point on the earth's surface, that is, the angle between north and true north when the magnetic needle is at rest. Shen Kuo is the first in the world to prove by experiments that the magnetic needle can be steered, but it tends to be slightly eastward, that is, the magnetic north and south poles are not completely coincident with the geographical north and south poles, and there is a magnetic declination. This is more than 400 years before Columbus discovered the phenomenon of magnetic declination when crossing the Atlantic Ocean.