Galileo galilei (1564 ~ 1642) is an Italian astronomer, mechanic, philosopher, physicist and mathematician. /kloc-0 was born in Pisa on February 5th, 564, and 1642/kloc-0 died in Pisa on October 8th. Galileo's surname is Galileo, and his full name is galileo galilei, but now people usually call him Galileo by his first name instead of his last name. Because of translation problems, there are different opinions about surnames.

Galileo is subject to Galileo.

Life: Galileo started school in 1572, and moved to Florence with his family in 1575 to study in a monastery. 1589 was hired as a professor of mathematics at the University of Pisa. 159 1 year, teaching at the University of Padua in Venice. /kloc-returned to Florence in 0/609, 16 1 1 went to Rome and served as an academician of the Academy of Forestry. 1633 In February, he was sentenced to life imprisonment by the Roman Inquisition for "opposing the Pope and promoting evil learning". After 1638, my eyes gradually became blind, and the evening scene was bleak. 1642 65438+ died on1October 8th. More than 300 years later,1979165438+10/0, the Pope had to announce at a public meeting that Galileo's judgment 1633 was unfair. 1980, 10 In June, the case was retried, and a committee composed of world-renowned scientists with different religious beliefs was formed in Romania to study the whole story of Galileo's case, the relationship between science and religion, the scientific value of Galileo's theory and its contribution to modern scientific thought.

Main contributions: It can be divided into the following three aspects:

(1) mechanics Galileo was the first scientist to introduce experiments into mechanics. He determined some important mechanical laws through the combination of experiment and mathematics. 1582, after long-term experimental observation and mathematical calculation, he got the isochronous law of pendulum. Later, he dropped out of school on 1585 due to family financial difficulties. When he left the University of Pisa, he deeply studied the works of ancient Greek scholars Euclid and Archimedes. He wrote his first paper entitled "Balance" based on the principle of lever and buoyancy. Soon after, he wrote a paper on gravity, which revealed the essence of gravity and center of gravity for the first time and gave an accurate mathematical expression, so he became famous at one fell swoop. At the same time, he questioned many viewpoints of Aristotle.

During the period of 1589 ~ 159 1, Galileo made a detailed observation on the motion of falling objects. Theoretically and experimentally, it is denied that Aristotle, who has ruled for thousands of years, established the correct "law of free fall" on the "law of falling body motion", that is, under the condition of ignoring air resistance, balls with different weights fall to the ground at the same time, and the falling speed has nothing to do with the weight. According to the records of V. viviani, a student in Galileo's later years, the falling experiment was conducted in public on the leaning tower of Pisa, but Galileo's works did not clearly indicate that the experiment was conducted on the leaning tower of Pisa. So it has been controversial for several years.

Galileo made a detailed study on the basic concepts of motion, including center of gravity, speed and acceleration, and gave a strict mathematical expression. Especially the concept of acceleration is a milestone in the history of mechanics. With the concept of acceleration, the dynamic part of mechanics can have scientific basis, while before Galileo, only the static part was described quantitatively.

Galileo informally put forward the law of inertia (see Newton's law of motion) and the law of motion of objects under the action of external forces, which laid the foundation for Newton to formally put forward the first and second laws of motion. Galileo was the pioneer of Newton's creation of classical mechanics.

Galileo also put forward the law of resultant force and projectile motion's law, and established Galileo's relativity principle. Galileo's contribution to mechanics is various. This is described in detail in his mechanical book Dialogue between Two New Sciences and Mathematical Proof written in his later years. In this immortal book, besides dynamics, there are many contents about mechanics of materials. For example, he expounded the bending test and theoretical analysis of beams, and correctly summarized the mechanical similarity relationship between the bending capacity and geometric dimensions of beams. He pointed out that for cylindrical beams of similar length, the bending moment is proportional to the cube of radius. He also analyzed the simply supported beam under concentrated load and correctly pointed out that the maximum bending moment is under load and is proportional to the product of its distance to two points. Galileo also analyzed the problems that should be paid attention to when applying the beam bending theory to practice, and pointed out that the size of engineering structures should not be too large, because they would be destroyed under their own weight. According to his experiments, he came to the conclusion that when the body size of animals decreases, the strength of their bodies does not decrease proportionally. He said, "A puppy may be able to carry two or three dogs of the same size, but I believe a horse may not be able to carry a horse of the same size."

Astronomy He was the first scientist who made great achievements in observing celestial bodies with a telescope. These achievements include: the discovery that the surface of the moon is uneven, Jupiter has four satellites (now called Galileo satellites), the rotation of sunspots and the sun, the profit and loss of Venus and Jupiter, and the Milky Way is composed of countless stars. He confirmed Copernicus's "theory of earth movement" with experiments, and completely denied Aristotle and Ptolemy's "theory of earth movement" which ruled for more than 1000 years.

(3) Philosophy Throughout his life, he insisted on fighting against idealism and scholasticism of the church, advocated using concrete experiments to understand the laws of nature, and believed that experience was the source of theoretical knowledge. He denied the existence of absolute truth and absolute authority to master the truth in the world, and opposed blind superstition. He acknowledged the objectivity, diversity and infinity of matter, which is of great significance to the development of materialist philosophy. However, due to historical limitations, he emphasized that only material attributes that can be summarized as quantitative characteristics exist objectively.

Galileo "abandoned" Heliocentrism because he supported Heliocentrism's imprisonment. He said, "Considering various obstacles, the shortest line between two points is not necessarily a straight line". It is precisely because of this idea that he temporarily gave up for eternal support, instead of being as brave as Bruno, he could continue to contribute his strength to science.

Galileo Galileo (1564- 1642) was a great astronomer, physicist, mechanic and philosopher in the late Italian Renaissance. He was also a pioneer of modern experimental physics and was known as the "father of modern science". He is an indomitable truth fighter. Engels called him "one of the giants who can break old theories and create new ones regardless of any obstacles".

I. Galileo's life

Galileo was born in Pisa, on the west coast of Italy, on February 1564. He was originally from Florence and came from a noble family. Galileo's father was a frustrated musician, proficient in Greek and Latin, and quite accomplished in mathematics. So Galileo received a good family education from an early age.

At the age of twelve, Galileo entered the monastery of Varosha near Florence and received a classical education. At the age of seventeen, he entered the University of Pisa to study medicine and devoted himself to studying physics and mathematics. Due to the financial difficulties of his family, Galileo left the University of Pisa without a diploma. In a difficult environment, he still insisted on scientific research, studied many works of Euclid and Archimedes, made many experiments and published many influential papers, which attracted great attention from the academic circles at that time and was called "the contemporary Archimedes".

Galileo studied mathematics at the University of Pisa at the age of 25. Two years later, Galileo angered the church and lost his job because of the famous experiment on the leaning tower of Pisa. After leaving the University of Pisa, Galileo went to teach at the University of Padua in Venice in 1592 until 16 10. This period was the golden age of Galileo's scientific research. Here, he has made fruitful achievements in mechanics and astronomy.

16 10, Galileo published his book in the form of popular reading, named "Star Messenger". This book was published in Venice, which caused a sensation in Europe at that time and won a high honor for Galileo. Galileo was hired as "court philosopher" and "court chief mathematician", and he returned to his hometown of Florence.

Galileo continued his scientific research in the court of Florence, but his astronomical discoveries and works clearly reflected the views of Copernicus and Heliocentrism. Therefore, Galileo began to attract the attention of the church. From 16 16, Galileo began to be brutally persecuted by the Roman Inquisition for more than 20 years.

Galileo lived a miserable life in his later years, and celeste, who took care of his daughter, died before him. The grief of losing his beloved daughter blinded Galileo. Even under such conditions, he still didn't give up his scientific research work.

1642 65438+1At 4 o'clock on the morning of October 8, the great Galileo, a lifelong fighter for science and truth, and a giant of science, died at the age of 78. On the eve of his death, he repeated this sentence: "It takes special courage to pursue science."

Galileo and his scientific discoveries

In ancient Greece, there were two schools of physics, one represented by the philosopher Aristotle and the other by the natural scientist Archimedes. Both of them are famous scholars in ancient Greece, but their scientific conclusions are different because of their different viewpoints and methods, forming a sharp opposition. Aristotle's view is basically idealistic, and he draws conclusions by subjective thinking and pure reasoning, so it is full of fallacies. Archimedes' view is basically materialistic, and he relies entirely on scientific practice to draw conclusions.

However, since 1 1 century, with the support of the Christian church, Aristotle's works have attracted the attention of scholastic philosophers, who rejected Archimedes' physics and regarded Aristotle's physics as a classic, and all scholars who violated Aristotle's physics were regarded as "heresies". But Galileo was skeptical about Aristotle's physics. On the contrary, he paid special attention to the study of Archimedes physics. He attaches importance to integrating theory with practice, observes various natural phenomena and thinks about various problems. When Galileo was eighteen, he once went to the church in Pisa. He noticed that the ever-burning lamp hanging in the church was regularly swung from left to right by the wind. He timed the pulse and found that the reciprocating time was always equal. In this way, he discovered the synchronicity of pendulum. Later, the Dutch physicist Huygens made a hanging pendulum clock according to this principle, which was called "Galileo clock".

According to Archimedes' theory, Galileo studied the hydrostatic balance for rapidly determining alloy composition, invented the "small balance" for measuring material density, and wrote a paper called "small balance". Later, he devoted himself to studying the geometry of the center of gravity of objects, and published the article "Center of Gravity of Solids" in 1588, which attracted the attention of academic circles. The following year, on the recommendation of a friend, he was hired as a professor of mathematics by the University of Pisa.

Aristotle believes that two objects fall at the same height, and the heavier object falls first than the lighter one. But after repeated research and experiments, Galileo came to the opposite conclusion: the falling speed has nothing to do with the weight. 1590, Galileo made a falling experiment on the leaning tower of Pisa, which proved that Aristotle's statement was wrong, which shook Aristotle's theory that ruled people's thoughts for more than 2000 years for the first time. However, some famous scholars invited to watch denied what they saw with their own eyes, and they attacked Galileo. Galileo was expelled from Pisa in 159 1 year.

In the history of science, Galileo was not the initiator of the falling body experiment, but Stevin. But Galileo's experiment on the leaning tower of Pisa had a far-reaching impact.

1592, Galileo came to teach at the University of Padua in Venice and began the golden age of his scientific activities. During this period, he studied many physical problems, such as slope motion, force synthesis, projectile motion and so on. He also studied liquids and heat and invented the thermometer. 1609, Galileo made an astronomical telescope and used it to explore the mysteries of the universe. He found that the surface of the moon was uneven, with mountains and deep valleys. Jupiter has four satellites revolving around it, and Venus, like the moon, has both gains and losses. Saturn has a halo; The sun has sunspots and can rotate. The Milky Way in Qian Qian is made up of thousands of dim stars. These findings provide strong evidence for the views of Copernicus and Bruno. This dealt a serious blow to the creed of the church.

The following year, he published "Star Messenger", which introduced the sky phenomenon he observed and publicized his views. This book caused a great sensation in Europe, so Galileo was called "Columbus in the sky". 16 13 years, he published an article about sunspots in Rome. The book clearly points out in the form of letters that Copernicus' theory is correct and Ptolemy's theory is wrong. Galileo angered the church and began to be tried by the Inquisition.

Under the pressure of the Holy See, Galileo continued his scientific research, and became more convinced of the correctness of Copernicus' theory through long-term observation and study of celestial movement. 1632 65438+ 10 In Florence, Galileo published Dialogue on Ptolemy and Copernicus. In the book, he talked for four days in the form of a dialogue between three scholars. Discuss three questions: 1, which proves that the earth is moving; 2. Enrich Copernicus' theory; 3. the tides of the earth. Dialogue summarizes Galileo's scientific discoveries in his long-term scientific research practice, declares the bankruptcy of Ptolemy's geocentric theory, fundamentally shakes the supreme authority of the church, and thus promotes the development of materialism. Once published, this book was welcomed by readers. But it was opposed by the Roman church. Galileo was imprisoned for a long time.

1636, Galileo secretly completed another masterpiece in his life, Dialogue between Two New Sciences. The book was published in the Netherlands on 1638. This masterpiece is also written in the form of a three-person dialogue. The first day is about the strength of solid materials, which refutes Aristotle's view that the speed of falling objects depends on the weight. "The Next Day" is about the reason of connection, and it discusses the proof of lever principle and the strength of beam. On the third day, we discussed uniform motion and natural acceleration motion. The fourth day is about the discussion of projectile motion. This masterpiece fundamentally denies Aristotle's theory of motion.

Three. Galileo's scientific research methods

Galileo proved the laws of physics very strictly. He established a scientific research method of experimental research on physical phenomena and combining experimental methods with mathematical methods and logical argumentation. For example, in order to illustrate inertia, he designed an ideal experiment without friction: hanging a simple pendulum at a certain point O, pulling the pendulum ball to the left point A at a certain distance from the vertical position, releasing the pendulum ball, and the pendulum ball will swing to the right point B of the vertical position, at which point A and point B are at the same height. If you change the path of a simple pendulum with a nail directly under O, the ball will be placed at the same height as A and B, and Galileo pointed out that the same conclusion will be reached for the inclined plane. He butted two inclined planes together, let the ball roll down from a static state along one inclined plane, and the ball would roll up the other inclined plane. If there is no friction, the ball will rise to its original height. He concluded that if the inclination of the second inclined plane was reduced, the ball would have to travel a longer distance to reach its original height on this inclined plane. Continue to make the inclination of the second inclined plane smaller and smaller, and the ball will roll farther and farther. If the second inclined plane is changed to a horizontal plane, the ball will never reach its original height, but will continue to move at a constant speed along the horizontal plane. Although the experiment designed by Galileo is fictitious, it is based on reliable facts. Idealization of the things studied can highlight the main characteristics of things, simplify the complex and understand its laws easily. Galileo's new method of natural science has strongly promoted the development of physics, so he is known as "the founder of classical physics".

Four. Galileo's position in the history of science

Galileo's scientific discovery occupies an extremely important position not only in the history of physics, but also in the whole history of science. He not only corrected the wrong view of Aristotle who ruled Europe for nearly two thousand years, but also created a new method to study natural science.

In summing up his scientific research methods, Galileo said, "This is the first time to open the door for a new method, which will bring many wonderful results and will win many people's attention in the next few years." Later, Huygens continued Galileo's research work, and he derived the periodic formula of simple pendulum and centripetal acceleration's mathematical expression. After systematically summarizing the work of Galileo and Huygens, Newton got the law of universal gravitation and Newton's three laws of motion. Galileo's spiritual wealth left to future generations is precious. Einstein once commented: "Galileo's discovery and the scientific reasoning method he used are one of the greatest achievements in the history of human thought, marking the real beginning of physics!"

"Galileo"

Famous experiment

Anyone who travels to Italy will never forget to visit the famous Leaning Tower of Pisa.

The Leaning Tower of Pisa is an ancient building in Pisa, central Italy. It was originally a bell tower of Pisa Cathedral. This 54.5-meter-high eight-story cylindrical building was started in 1 174. Due to the weak foundation, the tower was found to be tilted just after it was built on the third floor and had to stop working. After more than a century, people continued to build, so when it was completed at 1350, this Roman marble building was like a crooked tree, which could never be straightened. Since then, more than 600 years have passed, and the leaning tower of Pisa has tilted 5.3 degrees to the south, which is about 1mm every year. However, despite the tilt of the tower and the constant earthquakes, this ancient tower still stands in the city of Pisa, becoming a famous miracle in the history of world architecture.

But the Leaning Tower of Pisa is famous all over the world, not only for the above reasons, but also because it is closely related to an important event in the history of scientific discovery.

It was a sunny day on 1590. A 25-year-old red-haired young scientist led several young college students through the crowded square of tourists, got into the arched ticket gate at the bottom of the leaning tower, and then climbed the stairs along the spiral inside the tower. Not long after, the tourists gathered in the square found that there were college students at the arched ticket gate outside the leaning tower of Pisa, and the young scientist with red hair climbed to the top of the tower.

"Hey, what are they doing?" An Italian businessman with a beard in the square asked a snack vendor nearby puzzled.

"Sir, they are students from the University of Pisa." The vendor with a white apron around his waist replied:

"I heard that they are doing some real things ... experiments."

The vendor is right, because there are still several college students in the square asking tourists to leave the leaning tower to avoid being hurt by things thrown by people on the tower.

While speaking, the red-haired young scientist at the top of the tower shouted; "Are you ready?"

The heads sticking out of each floor shouted in unison, "All right, we can start!" " "

At this time, college students on all floors of the tower are stretching, holding a heavy box in their hands and a glass hourglass beside them. At that time, there was no accurate stopwatch, and the hourglass was a tool for calculating time. That box contains two objects of different weights, some are two iron balls of different sizes, some are stones of different sizes, and some even have ink bottles and quills. This box is specially made. Just press a button and the bottom cover will open automatically.

The experiment began. Only the red-haired young scientist at the top of the tower made a phone call, and the college students at the bottom pressed the button. At this time, I saw the box open and two objects with completely different weights fell quickly. A few seconds later, people in the square heard a bang and two objects landed at the same time.

Followed by the second, third and fifth floors ... repeat the experiment in turn. Finally, the red-haired young scientist at the top of the tower still holds a box with two iron balls of different sizes. He pressed the button and the iron ball flew down quickly, and the result also landed at the same time. The time recorded by the hourglass illustrates the truth that objects with different weights fall from the same height and reach the ground at the same time.

The experiment succeeded! Although the tourists in the square are not interested in this experiment at all, this experiment has shaken a "truth" that no one has doubted for thousands of years. This "truth" was put forward by the ancient Greek philosopher Aristotle. He thinks that when an object falls from a height, its speed depends on its weight. The heavier the object, the faster it falls.

The Leaning Tower of Pisa experiment overturned this authoritative conclusion.

Who is this red-haired young scientist who dares to challenge authority? He is a famous Italian mathematician, astronomer and physicist.

Choose the road

1564 February 15, Galileo was born in a humble aristocratic family in Pisa, Italy. It is said that his ancestors were famous doctors in Florence, but by his father Galileo Van Sandu's generation, his family had fallen. Van San is a talented composer. He published several pastoral poems and instrumental works before his death. He is also good at mathematics and proficient in Greek and Latin. However, wonderful music can't fill a family's stomach, and his mathematical talent can't get him a good position. Shortly after Galileo was born, Van Sandu opened a small shop selling woolen goods in Florence, not far from Pisa, which was a last resort. But in order to support his family, Fan Sandu had to go into business against his will.

Galileo Jr. is the eldest son of Fan Sandu, and his father placed great hopes on his son. He found that Galileo Jr. was very clever and had a strong curiosity about everything since he was a child. Not only that, the child is ingenious, and it seems that he has never been idle, either painting or playing the piano. He often makes many clever motor toys for his brothers and sisters and has a good time.

Van Sandu witnessed all this. Once, he said to his wife, "Galileo seems to be interested in everything." What will he do in the future? "

"Yes, he is very talented in music. Maybe he can be trained as a musician, just like you ... "His wife said.

Fan Sandu frowned and shook his head and said, "No, I've heard enough music. I can't let my children go this way! " "

The wife looked at her husband puzzled and asked cautiously, "So, what do you mean ..."

Fan Sandu said confidently, "I want to train him to be an outstanding doctor, respected like our ancestors, with rich income, which can bring honor, status and money to our family ..."

The wife looked at her husband's excited expression and knew that this was an idea that Fan Sandu had considered for a long time. She didn't refute, just sighed and said, "I hope so." Maybe children will live up to your expectations ... "

Galileo junior first entered the school of Frenborosa Monastery. In this school, he concentrates on philosophy and religion. For a time, Galileo hoped to be a missionary dedicated to the church in the future. But when Fan Sandu heard this, he immediately took his son home. He persuaded Galileo to study medicine, which he had already designed for his son's future.

/kloc-At the age of 0/7, Galileo entered the famous University of Pisa. According to his father's wishes, he became a medical student. The University of Pisa is an ancient university, and its library is rich in books, just to Galileo's taste. However, Galileo was not very interested in medicine. He seldom attends class, and as soon as he attends class, he puts forward such and such questions about what the professor teaches, which makes it difficult for the professor to answer. In the eyes of the professor, Galileo was a very unpopular bad student. However, Galileo was not interested in medicine. He studied mathematics, physics and other natural sciences tirelessly, and looked at those theories that have been regarded as classics since ancient times with suspicion.

You know, Galileo lived in a famous Renaissance era in European history, and Italy was the birthplace of the Renaissance. At that time, many big cities in Italy, such as Florence, Genoa and Venice, developed into the centers of East-West trade, established firms, workshops and the earliest banks, and the capitalist relations of production sprouted. Coupled with the development of trade and the invention of printing, new ideas spread faster than ever before. As a result, people began to shake the religious theology and traditional dogma that had bound their thoughts for thousands of years.

By chance, Galileo listened to a lecture by court mathematician Matteo Leach. Galileo was deeply fascinated by the young mathematician's profound knowledge and strict logic, especially his verification method in proving mathematical problems. His eyes lit up, as if he had discovered a magical world, which was his dream mathematics kingdom! He was so excited that he immediately went to court mathematician Matteo Leach and asked him many puzzling questions.

Matteo Leach came to Pisa with the Archduke of Tuscany from Florence. He taught mathematics to court attendants, but he didn't expect an enthusiastic audience. And his questions are very interesting, which fully shows his extraordinary wisdom and profound knowledge.

When matteo Leach heard that Galileo was a medical student at the University of Pisa, he couldn't help blurting out, "Ah, Galileo, you are a genius, and you will become an outstanding mathematician."

Galileo blushed. He talked about his boredom with medicine, his father's expectation of him, and his distress that he could not study according to his own wishes.

"Don't be discouraged." Matteo Leach said kindly, "You should study hard by yourself. If you have any difficulties, I will always be your loyal friend. "

Encouraged by Matteo Leach, Galileo studied mathematics and physics more and more diligently. He carefully read every book borrowed from the court mathematician and absorbed it like a sponge. However, he is not the kind of person who is superstitious about books. Those authoritative conclusions that people think are true often bring unexpected problems in Galileo's mind. He often feels distressed and falls into deep thinking.

On one occasion, Galileo strolled to his familiar Pisa Cathedral. He sat on a bench and stared at the beautifully carved altar and arched colonnade. Suddenly, the giant lamp in the center of the church hall shook, and it was the house repairman who installed the chandelier there.

This was originally a very common thing. The chandelier swings like a pendulum, drawing an invisible arc in the air. However, Galileo followed the swaying chandelier as if he had been touched by electricity. At the same time, he used his right hand to count the number of times the chandelier swings and the number of times the pulse beats according to the pulse of his left wrist, thus calculating the swinging time of the chandelier.

As a result of this calculation, Galileo discovered a secret, that is, the time for the chandelier to swing once is always the same, regardless of the radian. At first, the chandelier swung badly, and gradually, it slowed down, but every time it was swung, the number of pulse beats was the same.

Galileo's mind churned, and it occurred to him that it was clearly written in the book that short arcs passed faster than long ones. This is what the ancient Greek philosopher Aristotle said, and no one doubts it. Is there something wrong with your eyes or something?

He ran back to the university dormitory like a madman and repeated the experiment behind closed doors. He found ropes and chains of different lengths, as well as iron balls and wooden balls from somewhere. On the roof, on the branches outside the window, I repeated over and over again, recording the time of swinging with an hourglass. Finally, Galileo had to boldly come to the conclusion that Aristotle's conclusion was wrong. It is the length of the rope that determines the swing period, which has nothing to do with the weight of the object at the end of the rope. In addition, the vibration period is the same for the pendulum rope with the same length. This is the law of pendulum motion discovered by Galileo.

Galileo need not say how happy he was. But at that time, who would believe a medical student's scientific discovery, not to mention whether his conclusion established the famous Aristotle's authoritative statement.

Just then, Fan Sandu's shops became more and more depressed. It is said that Galileo did not study medicine according to his own wishes, but was obsessed with unimportant experiments all day. So his stern father decided to stop Galileo from continuing to go to college and let him go home to be a clerk.

Galileo was very depressed. He left the University of Pisa and returned to Florence. But the path he chose is unshakable.

Believe in science

On a quiet street in Florence, there is a shop with a small facade and light business, that is, the woolen goods shop opened by Fan Sandu. Every day, when passers-by pass by in a hurry, Galileo with red hair can always be seen sitting in front of the counter, lost in thought, or fiddling with some inexplicable things, such as scales, iron blocks and plates. And more often, he is immersed in reading. He was so absorbed in reading that even his father couldn't hear him shouting.

Since returning home, Galileo had to work as a clerk in his father's shop against his will, but he never forgot math and physics for a moment. Without basic learning conditions and no teacher to ask for advice, he tried his best to find some books on natural science and studied hard by perseverance. His favorite books are Euclid's Principles of Geometry and Archimedes' works.

Principle of Geometry is the earliest geometric work in the world. The works of Archimedes, a Greek scientist, contain rich knowledge of mathematics and mechanics, especially some physical experiments, which are very attractive to Galileo.

When it comes to experiments, Galileo is most interested. When he was still at the University of Pisa, he began to make one.

The "pulse meter" designed by him according to the movement law of the pendulum can be used to measure the patient's pulse beating, which is very popular with doctors. Now in my father's shop, I can't talk about the conditions of the experiment, but he still does the experiment with some daily necessities. Although it was inevitable that he would be scolded by his father, he did it anyway.

Archimedes' experiment of checking the king's crown inspired him. While repeating the experiment, he thought of using this method. At that time, the maritime industry in European countries was on the rise, which promoted the development of shipbuilding and machinery manufacturing, mining and metallurgy, and in turn raised many new problems for science and technology. Galileo then turned his attention to the study of the physical and mechanical properties of alloys. Soon, by measuring the weight of an object in the water, he found that throwing it into the water reduced the weight exactly equal to the weight of the water it displaced. On the basis of this important discovery, Galileo invented the specific gravity scale, which can easily determine the specific gravity of various alloys. He also wrote a paper, which introduced the construction principle and use method of the specific gravity scale in detail. This story soon spread in Florence and other cities.

1589 In the summer, Galileo, who taught himself in a shop in Florence for four years, was awarded the title of court mathematician matteo Leach. /ca & gt；