Brief introduction of physicist Newton

I don't know what I look like to others. But in my own opinion, I am just like a child playing on the seashore, complacent about finding a pebble smoother than usual or a shell more beautiful than usual from time to time, but I have not found the vast ocean of truth before me at all.

-Newton

Young Newton

On January 4, 1643, Newton was born in a farmer's family in Wolthorpe, a small town in Lincolnshire, England. Newton was a premature baby, weighing only three pounds at birth. The midwife and his relatives were worried about whether he would survive. No one expected that this seemingly insignificant little thing would become a giant of science, and live to the age of 85.

Newton's father died three months before he was born. When he was two years old, his mother remarried to a priest and left Newton to be raised by his grandmother. At the age of 11, my mother's stephusband died, and my mother returned to Newton with a son and two daughters born with her stephusband. Newton was taciturn and stubborn since childhood, which may come from his family situation.

From about the age of five, Newton was sent to public schools. Newton was not a child prodigy when he was a teenager. His qualifications were average and his grades were average, but he liked reading books, reading books that introduced various simple mechanical model making methods, and was inspired by them to make some strange gadgets by himself, such as windmills, wooden clocks, folding lanterns and so on.

It is said that young Newton made a model mill by himself after understanding the mechanical principle of windmill. He tied the mouse to a treadmill with wheels, and then put a corn in front of the wheel, which happened to be out of reach of the mouse. The mouse wants to eat corn, so it keeps running, so the wheel keeps turning; Once again, when he flew a kite, he hung a small lamp on the rope. At night, the villagers looked surprised that a comet appeared. He also made a small water clock. Every morning, the small water clock will automatically drop water on his face to urge him to get up. He also likes painting and carving, especially carving sundials. His sundials are placed everywhere in the corner and windowsill of his house to see the movement of the sun shadow.

Newton entered Grantham Middle School not far from home when he was 12 years old. Newton's mother had hoped that he would become a farmer, but Newton himself had no intention of doing so and loved reading. With the increase of age, Newton became more and more fond of reading, meditating and doing small scientific experiments. When he was studying in Grantham Middle School, he stayed at a pharmacist's house, which made him influenced by chemical experiments.

Newton's academic performance in middle school was not outstanding, but he just loved reading, and he was curious about natural phenomena, such as colors and the movement of the sun and shadows, especially geometry, Copernicus's Heliocentrism and so on. He also takes reading notes in different categories, and likes to make ingenious gadgets, tricks, inventions and experiments.

At that time, British society was permeated with new Christian ideas, and Newton's family had two relatives who were both priests, which may affect Newton's religious life in his later years. From these ordinary environments and activities, we can't see that Newton was a child with outstanding talents.

Later, forced by life, his mother asked Newton to stop school and farm at home to support his family. But Newton buried a book whenever he had the chance, so that he often forgot to work. Every time, when his mother told him to go to the market with the servant and get familiar with the business of trading, he begged the servant to go shopping alone, while he hid behind the trees and read a book. Once, Newton's uncle became suspicious and followed Newton to the listed town. He found his nephew sprawled on the grass, absorbed in a math problem. Newton's studious spirit touched his uncle, so he persuaded his mother to let Newton go back to school and encouraged him to go to college. Newton went back to school, devouring the nutrition from books.

years of study

In 1661, Newton, aged 19, entered Trinity College of Cambridge University as a fee-reducing student, and paid his tuition by doing chores for the college. In 1664, he became a scholarship winner and obtained a bachelor's degree in 1665.

In the middle of 17th century, the education system of Cambridge University was still permeated with a strong smell of medieval scholasticism. When Newton entered Cambridge, there were still some scholasticism courses, such as logic, ancient prose, grammar, ancient history, theology and so on. Two years later, a new atmosphere appeared in Trinity College. Lucas created a unique lecture, which stipulated that natural science knowledge should be taught, such as geography, physics, astronomy and mathematics.

isaac barrow, the first professor of the lecture, is a learned scientist. The scholar had a unique eye and saw that Newton had profound observation and keen understanding. So he taught Newton all his mathematical knowledge, including the method of calculating the area of curve graphics, and led Newton to the research field of modern natural science.

During this period of study, Newton mastered arithmetic and trigonometry, read Kepler's Optics, Descartes' Geometry and Principles of Philosophy, Galileo's Dialogue between Two World Systems, Hooke's Microscopic Atlas, and the history and early philosophical journals of the Royal Society.

Newton's time under Barrow's door was a crucial period for his study. Barrow is 12 years older than Newton, and he is good at mathematics and optics. He greatly appreciates Newton's talent and thinks that Newton's mathematics is better than himself. Later, Newton recalled: "Dr. Barrow taught courses on kinematics at that time, and perhaps it was these courses that prompted me to study this issue."

At that time, Newton relied largely on self-study in mathematics. He studied Euclid's Elements of Geometry, Descartes' Geometry, Wallis' arithmetica infinitorum, Barrow's Lecture Notes on Mathematics and the works of many mathematicians. Among them, Descartes' Geometry and Wallis' arithmetica infinitorum had a decisive influence on Newton, which quickly led Newton to the forefront of mathematics at that time-analytic geometry and calculus. In 1664, Newton was elected as Barrow's assistant, and the following year, the Cambridge University Council passed the decision to grant Newton a bachelor's degree.

In 1665 ~ 1666, the severe plague swept through London, and Cambridge was not far from London. Because of the fear of contagion, the school was closed, and Newton left school and returned home in June 1665.

Because Newton was influenced and cultivated by mathematics and natural science in Cambridge, he had a strong interest in exploring natural phenomena, and the quiet environment in his hometown made his thoughts spread their wings. The short period from 1665 to 1666 became the golden age of Newton's scientific career. He was full of thoughts in the field of natural science, and he was talented in generate. He thought about problems that his predecessors had never thought about, stepped into fields that his predecessors had not involved, and created unprecedented amazing achievements.

At the beginning of 1665, Newton founded the approximation method of series and the rule of transforming binomial with arbitrary power into a series. In November of the same year, the positive flow number method (differential) was established; In January of the following year, the color theory was studied with a prism; In May, I began to study the reverse flow number method (integral). During this year, Newton began to think of studying gravity and wanted to extend the theory of gravity to the orbit of the moon. He also deduced from Kepler's law that the force that keeps the planets in their orbits must be inversely proportional to the square of their distance from the center of rotation. Newton realized the legend of gravity when he saw the apple fall to the ground, and it was also an anecdote that happened at this time.

In short, during his two years in his hometown, Newton engaged in scientific creation with more vigorous energy than ever after, and cared about natural philosophy. His three great achievements: calculus, gravitation and optical analysis were all conceived and formed at this time. It can be said that Newton at this time has begun to paint the blueprint of most scientific creations in his life.

Shortly after Easter in 1667, Newton returned to Cambridge University. On October 1st, he was elected as a junior college partner (junior college committee) of Trinity College. On March 16th of the following year, he obtained his master's degree and became a senior college partner (senior college committee). On October 27th, 1669, Barrow resigned as a professor in order to help Newton. At the age of 26, Newton was promoted to professor of mathematics and became a professor of Lucas Lecture. Barrow paved the way for Newton's scientific career. Without the help of Newton's uncle and Barrow, Newton, a swift horse, might not have galloped on the road of science. Barrow gave way to the wise, which has been passed down as a much-told story in the history of science.

great achievement ~ establishing calculus

Among all Newton's scientific contributions, mathematical achievements occupy a prominent position. The first creative achievement in his mathematical career was the discovery of binomial theorem. According to Newton's own recollection, it was in the winter between 1664 and 1665 that he tried to modify his series of finding the area of a circle while studying Dr. Wallis's arithmetica infinitorum.

Descartes' analytic geometry corresponds the functional relationship describing motion to the geometric curve. Newton found a new way out under the guidance of his teacher Barrow and on the basis of studying Descartes' analytic geometry. The speed at any moment can be regarded as the average speed in a small time range, which is the ratio of a small distance to a time interval. When this small time interval is reduced to infinity, it is the accurate value of this point. This is the concept of differentiation.

Differentiating is equivalent to finding the tangent slope of the relationship between time and distance at a certain point. The distance traveled by a variable-speed moving object in a certain time range can be regarded as the sum of the distances traveled in a small time interval, which is the concept of integral. Integrating is equivalent to finding the area under the curve of the relationship between time and speed. Newton established calculus from these basic concepts.

The establishment of calculus is Newton's most outstanding mathematical achievement. Newton founded this mathematical theory, which is directly related to physical concepts, in order to solve the problem of motion. Newton called it "flow counting". Some specific problems it deals with, such as tangent problem, quadrature problem, instantaneous velocity problem and function maximum and minimum value problem, have been studied by people before Newton. But Newton surpassed his predecessors. From a higher angle, he integrated the scattered efforts in the past, unified various skills of solving infinitesimal problems since ancient Greece into two kinds of ordinary algorithms-differential and integral, and established the reciprocal relationship between these two kinds of operations, thus completing the most critical step in the invention of calculus, providing the most effective tool for the development of modern science and opening up a new era in mathematics.

Newton did not publish the research results of calculus in time. He may have studied calculus earlier than Leibniz, but the expression adopted by Leibniz was more reasonable, and the works on calculus were published earlier than Newton.

When Newton and Leibniz argued about who was the founder of this subject, it actually caused an uproar. This quarrel lasted for a long time among their respective students, supporters and mathematicians, resulting in a long-term confrontation between mathematicians in continental Europe and British mathematicians. British mathematics was closed to the outside world for a period of time, limited by national prejudice, and stuck too rigidly in Newton's "flow counting", so the development of mathematics fell behind for a whole hundred years.

It should be said that the establishment of a science is by no means the achievement of one person. It must be concluded by one person or several people after the efforts of many people and the accumulation of a large number of achievements. The same is true of calculus, which was established independently by Newton and Leibniz on the basis of their predecessors.

In 177, Newton's algebra lectures were sorted out and published, and it was named General Arithmetic. He mainly discussed the basis of algebra and its application in solving various problems. The book states the basic concepts and operations of algebra, illustrates how to turn all kinds of problems into algebraic equations with a large number of examples, and deeply discusses the roots and properties of equations, which leads to fruitful achievements in equation theory. For example, he draws the relationship between the roots of equations and their discriminant, and points out that the sum of the powers of the roots of equations can be determined by using the coefficients of equations, that is, Newton's power sum formula.

Newton contributed to both analytic geometry and synthetic geometry. In Analytic Geometry published in 1736, he introduced the center of curvature, gave the concept of close line circle (or curve circle), put forward the curvature formula and the method of calculating the curvature of curve. And summed up many of his own research results into a monograph "Enumeration of Cubic Curves", which was published in 174. In addition, his mathematical work involves many fields such as numerical analysis, probability theory and elementary number theory.

Great Achievements ~ Three Contributions to Optics

Before Newton, Mozi, Bacon, Leonardo da Vinci and others all studied optical phenomena. The law of reflection is one of the optical laws that people have long known. When modern science rose, Galileo discovered the "new universe" through a telescope, which shocked the world. The Dutch mathematician Sneer first discovered the law of refraction of light. Descartes put forward the theory of particles of light ...

Newton and his contemporaries, such as Hooke and Huygens, also studied optics with great interest and enthusiasm like Galileo and Descartes. In 1666, when Newton was on vacation at home, he got a prism, which he used for the famous dispersion experiment. After a beam of sunlight passes through the prism, it is decomposed into spectral bands of several colors. Newton blocked the light of other colors with a slit baffle, and only let the light of one color pass through the second prism, and the result is only the light of the same color. In this way, he discovered that white light is composed of different colors of light, which is the first major contribution.

in order to verify this discovery, Newton tried to combine several different monochromatic lights into white light, and calculated the refractive index of different colors of light, which accurately explained the dispersion phenomenon. The mystery of the color of matter is solved. It turns out that the color of matter is caused by the different reflectivity and refractive index of different colors of light on the object. In 1672, Newton published his research results in the Journal of Philosophy of the Royal Society, which was his first published paper.

many people study optics in order to improve refractive telescopes. Newton discovered the composition of white light, and thought that the dispersion phenomenon of refractive telescope lens could not be eliminated (later, some people eliminated the dispersion phenomenon with lenses made of glasses with different refractive indexes), so he designed and manufactured the reflecting telescope.

Newton is not only good at mathematical calculation, but also able to make all kinds of experimental equipment and do fine experiments by himself. In order to make a telescope, he designed a grinding and polishing machine and experimented with various grinding materials. In 1668, he made the first reflecting telescope prototype, which was the second greatest contribution. In 1671, Newton presented the improved reflecting telescope to the Royal Society. Newton became famous and was elected as a member of the Royal Society. Reflecting telescope's invention laid the foundation of modern large-scale optical astronomical telescope.

At the same time, Newton also carried out a lot of observation experiments and mathematical calculations, such as studying the abnormal refraction phenomenon of glacier stones discovered by Huygens, the color phenomenon of soap bubbles discovered by Hooke, the optical phenomenon of Newton's ring and so on.

Newton also put forward the particle theory of light.