Chinese name: isaac newton.
Isaac Newton
Nationality: UK
Birthplace: Elshop Village, Lincolnshire, England
Date of birth:1643 65438+1October 4th.
Date of death:1March 20, 727
Occupation: professor, scientist, alchemist
Graduate school: Cambridge University, UK
Faith: Christianity
Major achievements: Inventing calculus.
Discover the law of universal gravitation
Create classical mechanics
Invented reflecting telescope.
Discovering the dispersion principle of light
Masterpiece: Mathematical Principles of Natural Philosophy
Place of death: Kensington, London, England
Newton was born on1643 65438+1October 4th in Walsop village near Grantham, Lincolnshire, England. 16 1 year entered Trinity College, Cambridge University, UK. 1665 discovered binomial theorem, and 1665 obtained a bachelor of arts degree.
Sir Newton
In the next two years, he escaped from the plague in his hometown, where he drew a blueprint for the most important scientific creation in his life. After Newton 1667 returned to Cambridge, he was elected as a member of Trinity College of Cambridge University and received his master's degree the following year. From 65438 to 0669, he served as Lucas Professor of Mathematics at Cambridge University until 170 1. From 65438 to 0696, he was the director of the Royal Mint and moved to London. 1703 president of the royal society. 1706 was knighted by Queen Anna. In his later years, Newton devoted himself to natural philosophy and theology. On March 3 1727, Newton died in London at the age of 84.
(Remarks: Newton's date of birth is julian calendar1642 65438+February 25th, that is, Gregorian calendar1643 65438+1October 4th; The date of death is March 20th, julian calendar 1727, which is March 30th, Gregorian calendar 1727. )
Young Newton
1643 65438+1October 4th, Newton was born in a farmer's family in Wolthorpe, Lincolnshire, England. Newton was a premature baby, weighing only three pounds at birth. The midwife and his relatives are worried about whether he will survive. No one expected that this seemingly insignificant little thing would become an immortal scientific giant and live to be 84 years old.
Three months before Newton was born, his father died. When he was two years old, his mother remarried to a priest and left Newton to his grandmother. 1 1 years old, my mother's stephusband died, and my mother returned to Newton with a son and two daughters born with her stepfather. 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. He has average qualifications and good grades.
Newton in childhood
Generally speaking, he likes reading, reading books about how to make simple mechanical models, and being inspired by them, he makes some strange gadgets by himself, such as windmills, wooden clocks, folding lanterns and so on.
Legend has it that young Newton made a model of the mill after thoroughly understanding the mechanical principle of the windmill. He tied the mouse to a treadmill with wheels, and then put a corn in front of the wheel, just out of the mouse's reach. The mouse wants to eat corn, so it keeps running, so the wheel keeps turning; Once again, when he was flying a kite, he hung a small lamp on the rope. In the evening, the villagers were surprised to find that a comet appeared. He also made a small water clock. Every morning, the water bell will automatically drop water on his face to wake him up. He also likes painting and carving, especially carving sundials. His sundial was placed in the corner of his house and everywhere on the windowsill to observe the movement of the shadow.
Newton entered Grantham Middle School not far from home at the age of 12. Newton's mother had hoped that he would become a farmer, but Newton himself had no intention of doing so and loved reading. As he grew older, Newton became more and more fond of reading, meditating and doing small scientific experiments. When he was studying in Grantham Middle School, he lived in a pharmacist's house, which influenced him by chemical experiments.
Newton's academic performance in middle school is not outstanding, but he just loves reading and is curious about natural phenomena, such as colors, the movements of the four seasons, especially geometry, Heliocentrism of Copernicus and so on. He also takes reading notes in different categories and likes to make ingenious gadgets, tricks, inventions and experiments.
At that time, English society was permeated with new Christian ideas, and two relatives of Newton's family were priests, which may affect Newton's religious life in his later years. From these ordinary environments and activities, we can't see that Newton is a gifted child.
Later, forced by life, his mother asked Newton to drop out of 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 his servant and get familiar with the trade business, he begged the servant to go shopping alone, while he hid behind a tree 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 and drew nutrition from books.
Years of study
Newton (10 sheets)
16 1 year, 19-year-old Newton entered Trinity College of Cambridge University as a tuition fee waiver, and paid for his tuition by doing chores for the college. 1664 became a scholarship winner, and 1665 received his bachelor's degree.
/kloc-In the mid-7th century, the education system of Cambridge University was still permeated with a strong flavor of medieval scholasticism. When Newton entered Cambridge, there were also some courses of scholasticism, such as logic, ancient prose, grammar, ancient history, theology and so on. Two years later, Trinity College took on a new look. Lucas created a unique lecture, which stipulated that natural science knowledge should be taught, such as geography, physics, astronomy, mathematics and so on.
The first professor of the lecture, Isaac Barrow, was a learned scientist. The scholar had a unique vision 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, and read Kepler's Optics, Descartes' Principles of Geometry and Philosophy, Galileo's Dialogue between Two World Systems, Hooke's Micro Atlas, and the historical and early philosophical journals of the Royal Society.
Newton's time under Barrow's door was the key period of his research. Barrow is older than Newton 12 years old and is good at mathematics and optics. He admired Newton's talent very much and thought that Newton's talent in mathematics surpassed himself. Newton later recalled: "Dr. Barrow taught courses in kinematics at that time, and perhaps it was these courses that prompted me to study this problem."
Newton relied heavily on teaching himself mathematics at that time. He studied Euclid's Elements of Geometry, Descartes' Geometry, Wallis' arithmetica infinitorum, Barrow's lectures on mathematics and the works of many mathematicians. Among them, Descartes' Geometry and Wallis' arithmetica infinitorum had a decisive influence on Newton, and Newton quickly moved to the forefront of mathematics at that time-analytic geometry and calculus. 1664, Newton was elected as Barrow's assistant, and the next year, the Council of Cambridge University passed the decision to grant Newton a bachelor's degree.
1665 to 1666, a serious plague swept through London, and Cambridge was not far from London. Because of fear, the school was closed, and Newton left school and went home in June 1665.
Because Newton was influenced and influenced 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 and fly. The short period from 1665 to 1666 became the golden age of Newton's scientific career. He is full of thinking in the field of natural science, brilliant and productive, thinking about problems that his predecessors have never thought about, stepping into fields that his predecessors have never set foot in, and creating unprecedented amazing achievements.
At the beginning of 1665, Newton established the approximation method of series and the law that binomial with arbitrary power is transformed into series; In June of the same year 165438+ 10, the forward serial number method (differential) was established; The following year (65438+ 10), the color theory was studied with 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 planets in orbit must be inversely proportional to the square of their distance from the center of rotation. The legend that Newton didn't realize gravity until he saw the apple fall to the ground was also an anecdote that happened at this time.
In a word, during his two years in his hometown, Newton engaged in scientific creation with more vigorous energy than before and cared about natural philosophy. His three great achievements: calculus, gravitation and optical analysis were conceived and formed at this time. It can be said that Newton at this time has begun to describe the blueprint of most scientific creations in his life.
1667 Shortly after Easter, Newton returned to Cambridge University. 1 June1day was elected as a specialist partner of Trinity College, and he obtained his master's degree on March 16 the following year, and became a specialist partner at the same time. 1669, 10 year1October 27th, Barrow resigned as a professor to help Newton. At the age of 26, Newton was promoted to professor of mathematics and served as Professor of Lucas. Barrow paved the way for Newton's scientific career. Without the help of Uncle Newton and Barrow, Newton, a swift horse, might not have galloped on the road of science. Barrow gave way to a wise man, which was told as a story in the history of science.
Establish 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, he discovered this theorem when he tried to modify his series of finding the area of a circle while studying Dr. Wallis' arithmetica infinitorum in the winter of 1664 and 1665.
Descartes' analytic geometry maps the functional relationship describing motion to geometric curves. 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 exact value of this point. This is the concept of differentiation.
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, maximum and minimum value of function, have been studied before Newton. But Newton surpassed his predecessors. He synthesized the scattered conclusions in the past from a higher angle, unified various skills of solving infinitesimal problems since ancient Greece into two common algorithms-differential and integral, and established the reciprocal relationship between these two 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 of mathematics.
Newton did not publish the research results of calculus in time. He may have studied calculus earlier than Leibniz, but Leibniz adopted a more reasonable expression, and his works on calculus were published earlier than Newton.
Between Newton and Leibniz, when arguing about who is the founder of this subject, it actually caused an uproar. This quarrel lasted for a long time among their students, supporters and mathematicians, which caused the long-term opposition between European continent mathematicians and British mathematicians. British mathematics was closed to the outside world for a period of time, limited by national prejudice, and too rigidly adhered to Newton's "flow counting", so the development of mathematics fell behind for a whole hundred years.
1707, Newton's algebra lecture notes were compiled and published, named "General Arithmetic". He mainly discussed the basis of algebra and its application in solving various problems. This book states the basic concepts and operations of algebra, explains how to turn various problems into algebraic equations with a large number of examples, and deeply discusses the roots and properties of equations, thus achieving fruitful results in equation theory. For example, he draws the relationship between the roots of equations and their discriminant, and points out that the power sum 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 by 1736, he introduced the center of curvature, gave the concept of closed line circle (or curve circle), and put forward the curvature formula and the curvature calculation method of curve. And summed up many of my own research results into a monograph "Counting Cubic Curves", which was published in 1704. In addition, his mathematical work involves numerical analysis, probability theory, elementary number theory and many other fields.
Newton in his later years
There are some misunderstandings about Newton in his later years. Think Newton began to believe in God. But this is not the case. The study of calculus was the focus of Newton's later years. Calculus can derive the functional form of the relationship between physical quantities on the basis of experiments, but the specific function is unknown (in short, we know who is directly or inversely proportional to whom, but the proportional coefficient as the initial condition is unknown), and we can only know it through experiments. Therefore, Newton put forward the concept of "God first pushes", that is to say, the inherent properties of substances such as density are formulated by nature itself and cannot be changed or deduced. People's misunderstanding generally comes from "God first pushes" and is misunderstood as "God first pushes" (Newton lived in an era of physical concepts without force, and Newton's laws were expressed by Newton in the form of momentum).
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Main contribution
binomial theorem
1665, Newton, who was only 22 years old, discovered the binomial theorem, which is an essential step for the all-round development of calculus. Binomial theorem is widely used in combinatorial theory, higher power, higher arithmetic progression summation and difference methods.
Promotion form
Binomial series expansion is a powerful tool to study series theory, function theory, mathematical analysis and equation theory. Today, we will find that this method is only applicable to the case where n is a positive integer. When n is a positive integer of 1, 2, 3, ..., the series ends at n+ 1 If n is not a positive integer, the series will not end, and this method is not applicable. But you know, Leibniz introduced the word function in 1694. In the early stage of calculus, it is the most effective method to treat transcendental function with the level of transcendental function.
Create calculus
Newton's most outstanding achievement in mathematics was the creation of calculus. His outstanding achievement is to unify all kinds of special skills to solve infinitesimal problems since ancient Greece into two general algorithms-differential and integral, and establish the reciprocal relationship between these two operations. For example, area calculation can be regarded as the inverse process of finding tangent.
At that time, Leibniz had just put forward a research report on calculus, which triggered a debate on the patent right of calculus invention until Leibniz died. Later generations think that Newton put forward the concept of calculus earlier, but Leibniz's method is more perfect. In the method of calculus, Newton's extremely important contribution is that he not only clearly saw, but also boldly used the methodology provided by algebra, which is much superior to geometry. He replaced the geometric methods of cavalieri, Gregory, Huygens and Barrow with algebraic method, and completed the algebra of integral. Since then, mathematics has gradually shifted from the subject of feeling to the subject of thinking.
In the early days of calculus, because there was no solid theoretical foundation, it was studied by some people who like to think. This led to the famous second mathematical crisis. This problem was not solved until the limit theory was established in19th century.
Equation theory and variational method
Newton also made a classical contribution to algebra, and his generalized arithmetic greatly promoted the theory of equations. He found that the imaginary roots of real polynomials must appear in pairs, and found the upper bound law of polynomial roots. He expressed the sum formula of the roots of polynomials by using the coefficients of polynomials, and gave a generalization of Cartesian sign rule that limits the number of imaginary roots of real polynomials.
Newton also designed a method to find the logarithm of the approximate values of the real roots of numerical equations and transcendental equations. The modification of this method is now called Newton method.
Newton also made great discoveries in the field of mechanics, which is a science to explain the motion of objects.
newton
The first law of motion was discovered by Galileo. This law shows that if an object is at rest or moving in a straight line at a constant speed, it will remain at rest or continue to move in a straight line at a constant speed as long as there is no external force. This law, also known as the law of inertia, describes a property of force: force can make an object move from rest to motion, from motion to rest, and can also make an object change from one form of motion to another. This is the so-called Newton's first law. The most important problem in mechanics is how objects move under similar circumstances. Newton's second law solved this problem; This law is considered to be the most important basic law in classical physics. Newton's second law quantitatively describes that force can change the motion of an object. Indicates the time change rate of speed (i.e. acceleration A is directly proportional to force F, but inversely proportional to the mass of the object, i.e. a=F/m or F = Ma). The greater the force, the greater the acceleration; The greater the mass, the smaller the acceleration. Both force and acceleration have magnitude and direction. Acceleration is caused by force, and the direction is the same as force; If several forces act on an object, the resultant force will produce acceleration. The second law is the most important, and all the basic equations of power can be derived from it by calculus.
In addition, Newton formulated the third law based on these two laws. Newton's third law points out that the interaction between two objects is always equal in size and opposite in direction. For two objects in direct contact, this law is easier to understand. The downward pressure of the book on the sub-table is equal to the upward support of the table on the book, that is, the action is equal to the reaction. So is gravity. The force that an airplane in flight pulls up the earth is numerically equal to the force that the earth pulls down the airplane. Newton's laws of motion are widely used in science and dynamics.
Newton's law of motion
Newton's law of motion is the general name of the three laws of motion in physics proposed by isaac newton, and it is regarded as the basis of classical physics.
Newton's first law (law of inertia: all objects always keep moving in a straight line or at rest without any external force until an external force forces them to change this state. -it clarifies the relationship between force and motion, and puts forward the concept of inertia), "Newton's second law (the acceleration of an object is directly proportional to the resultant force F acting on the object, and inversely proportional to the mass of the object, and the direction of acceleration is the same as that of the resultant force. Formula: F=kma (when the unit of m is kg and the unit of a is m/s2, k= 1) Newton's third law (the acting force and reaction force between two objects on the same line are equal in magnitude and opposite in direction). )"
Optical contribution
Before Newton, Mozi, Bacon, 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 a "new universe" through a telescope, which shocked the world. Dutch mathematician Hans sneer first discovered the law of refraction of light. Descartes proposed the particle of light. ...
Newton and his contemporaries, such as Hooke and Huygens, studied optics with great interest and enthusiasm, just like Galileo and Descartes. 1666, when Newton was on vacation at home, he got a prism, and he made a famous dispersion experiment with this prism. After a beam of sunlight passes through a prism, it is decomposed into several color spectral bands. Newton blocked the light of other colors with a slit baffle, and only let the light of one color pass through the second prism, resulting in only the light of the same color. In this way, he found that white light is composed of different colors of light, which is the first major contribution.
Newton telescope
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 has been 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 A.D. 1672, Newton published his research results in the Journal of Philosophy of the Royal Society, which was his first 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 lenses could not be eliminated (later, some people eliminated the dispersion phenomenon with lenses made of glass with different refractive indexes), so he designed and manufactured reflective telescopes.
Newton was 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 tested various grinding materials. 1668, he made the first prototype of reflective telescope, which is the second largest contribution. 167 1 year, Newton presented the improved reflective telescope to the royal society, which made him 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 stone 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, thinking that light is formed by particles and takes the fastest straight-line motion path. His "particle theory" and Huygens' "wave theory" later formed two basic theories about light. In addition, he also made Newton color wheel and other optical instruments.
Build a mechanical building
Newton is a master of classical mechanical theory. He systematically summarized the work of Galileo, Kepler and Huygens, and got the famous laws of gravity and Newton's three laws of motion.
Before Newton, astronomy was the most prominent subject. But why do planets have to orbit the sun according to certain rules? Astronomers cannot fully explain this problem. The discovery of gravity shows that the movements of stars in the sky and objects on the ground are governed by the same law-mechanical law.
Long before Newton discovered the law of gravity, many scientists had seriously considered this problem. For example, Kepler realized that there must be a force at work that makes the planet move along an elliptical orbit. He thinks this force is similar to magnetic force, just as a magnet attracts iron. 1659, Huygens found that a centripetal force was needed to keep the object moving in a circular orbit by studying the movement of the pendulum. Hooke and others thought it was gravity, and tried to deduce the relationship between gravity and distance.
1664, Hooke found that when comets approached the sun, their orbits were curved due to the sun's gravity. 1673, huygens deduced the law of centripetal force; 1679, Hooke and Halley deduced from centripetal force law and Kepler's third law that the gravitational force for maintaining planetary motion is inversely proportional to the square of distance.
Newton himself recalled that around 1666, he had considered the problem of gravity when he lived in his hometown. The most famous saying is that Newton often sits in the garden for a while during holidays. Once, as it happened many times before, an apple fell from the tree. ...
The accidental landing of an apple is a turning point in the history of human thought, which opens the mind of the person sitting in the garden and causes him to ponder: What is the reason why almost all objects are attracted by the center of the earth? Newton mused. Finally, he discovered the gravity which is of epoch-making significance to mankind.
Newton's genius lies in that he solved the mathematical argument problem that Hooke and others could not solve. 1679, Hooke wrote to Newton and asked him if he could prove that the planet moves in an elliptical orbit according to the law of centripetal force and the law that gravity is inversely proportional to the square of distance. Newton didn't answer the question. 1685, when Harley visited Newton, Newton had discovered the law of universal gravitation: there is gravitation between two objects, which is inversely proportional to the square of the distance and directly proportional to the product of the masses of the two objects.
At that time, accurate data such as radius of the earth and the distance between the sun and the earth were available for calculation. Newton proved to Harley that the gravity of the earth is the centripetal force that makes the moon move around the earth, and also proved that the planetary motion conforms to Kepler's three laws of motion under the action of solar gravity.
At the urging of Harley, at the end of 1686, Newton wrote an epoch-making masterpiece, Mathematical Principles of Natural Philosophy. The Royal Society is short of funds to publish this book. Later, one of the greatest works in the history of science was published in 1687 with Harley's support.
In this book, from the basic concepts of mechanics (mass, momentum, inertia, force) and basic laws (three laws of motion), Newton not only demonstrated the law of universal gravitation mathematically, but also established classical mechanics as a complete and rigorous system, unified celestial mechanics with ground object mechanics, and realized the first large-scale synthesis in the history of physics.
Newton's three scales
The law of material immortality refers to the immortality of material quality; The law of conservation of energy refers to the conservation of energy of matter; Law of conservation of momentum.
The Legend of Apple
Many books about Newton have legends about Newton and Apple: 1665- 1666. During this period, due to the prevalence of Kala-azar in Cambridge, the school was forced to close, and Newton, who just got his bachelor's degree from Cambridge, also returned to his hometown. One day, when Newton was sitting under an apple tree reading and thinking, an apple fell, which gave Newton inspiration at once. But it was later discovered by experts that the apple at that time did not hit Newton. And the diary of Newton's portrait Newton (19) recalls that the apple didn't hit him. The 23-year-old student immediately thought that the apple must be pulled down by the gravity of the earth. After years of hard work, he finally completed the elaboration, mathematical proof and formula derivation of the law of universal gravitation.
This story is widely circulated, but recently a historian raised an objection. He thought what he said was not true. His basis is as follows:
The French writer Voltaire (1694- 1778) first publicized this story. He has great enthusiasm for Newton's research results and actively publicizes them. 1726, he went to England, and wrote 25 newsletters that year, among which 15 newsletters mentioned the story of apple landing. He said in the article that Newton's niece told him the story. This is 1726.
Later in 1752, there was a friend of Newton (William Stukeley), 45 years younger than Newton. In his reminiscence article, Newton told this story one year before his death. Newton died in 1727, that is to say, Newton told this story himself in 1726.
So historians point out that in the same year (1726), if two people talked about it, who would speak first? Therefore, the story about Apple must be made up. Some people think that at least two things in this Apple story are inconsistent with the known historical facts:
First, gravity is not the independent discovery of Newton alone, but the result of gradual exploration and research accumulated by several people in history. It is unacceptable that some books are named after Newton's law of gravity. In addition, it is obviously a serious distortion of history to say that Newton discovered gravity as a natural result inspired by the fall of apples. Second, 1665, Newton did not fully understand the laws of motion of celestial bodies. If we admit this apple story, isn't it equivalent to advancing Newton's discovery of gravity by at least 20 years? In fact, Newton did not reach the final conclusion until more than 20 years later, and completed the mathematical demonstration and formula derivation.