Physics short story

Archimedes (about 287 ~ 2 BC12) was a physicist and mathematician in ancient Greece and the founder of statics and hydrostatics.

Except the great Newton and the great Einstein, no one has made such a great contribution to the progress of mankind as Archimedes. Even Newton and Einstein used to draw wisdom and inspiration from him. He is "the ideal embodiment of the combination of theoretical genius and experimental genius", and Leonardo da Vinci and Galileo in the Renaissance followed his example.

Start with the story of taking a bath.

There is such an interesting story about Archimedes. According to legend, King Guhennon of Silas asked craftsmen to make him a pure gold crown. When it was finished, the king suspected that the craftsman had mixed a fake gold crown, but the gold crown was as heavy as the pure gold originally given to the goldsmith. Did the craftsman play tricks? The problem of trying to test the authenticity without destroying the crown not only stumped the king, but also made the ministers look at each other.

Later, the king asked Archimedes to test it. At first Archimedes was also thinking hard, to the point. One day, he went to the bathhouse to take a bath. Sitting in the bathhouse, he saw the water overflowing and felt his body being gently pulled up. He suddenly realized that the proportion of gold crowns can be determined by measuring the displacement of solids in water. He jumped out of the bathtub excitedly and ran out without even considering his clothes, shouting "found it!" Eureka! " . Fureka means "I know".

After further experiments, he came to the palace. He put the crown and pure gold with the same weight in two jars filled with water, and compared the water overflowing from the two jars, and found that the jar with the crown overflowed more water than the other jar. This shows that the volume of the crown is larger than that of pure gold with the same weight, so it proves that other metals are mixed in the crown.

The significance of this experiment is far greater than finding out that the goldsmith cheated the king. Archimedes discovered the law of buoyancy: the buoyancy gained by an object in a liquid is equal to the weight of the liquid it discharges. Until modern times, people are still using this principle to calculate the specific gravity of objects and determine the load capacity of ships.

"If you give me a fulcrum, I can push the earth."

Archimedes is not only a theorist, but also a practitioner. Throughout his life, he was keen on applying his scientific discoveries to practice, thus combining the two. In Egypt around 1500 BC, people used levers to lift heavy objects, but people didn't know why. Archimedes devoted himself to this phenomenon and discovered the lever principle. Archimedes once said, "If you give me a fulcrum, I can push the earth."

At that time, King Hennon built a boat for the king of Egypt. It is big and heavy, and it has been stranded on the coast for many days because it can't move. Archimedes designed a complicated lever pulley system to be installed on the ship, and handed one end of the rope to King Henon. King Hennon gently pulled the rope, and a miracle appeared. The ship moved slowly and finally sank into the sea. The king was surprised and admired Archimedes very much. He sent someone to post a notice saying, "In the future, no matter what Archimedes says, you must believe him."

newton

When he was young, he used to lead a cow up the mountain and read a book at the same time. When he got home, he found only one rope in his hand. Cooking eggs regularly while reading will cause the watch and eggs to boil together in the pot; Once, he invited a friend to dinner at home, but he worked in the laboratory and forgot to eat or sleep. Repeatedly urged, he still didn't come out. When a friend finished eating a chicken and there was a pile of bones left on the plate, Newton remembered, but after seeing the bones on the plate, he suddenly said, "I thought I didn't eat, so I have already eaten."

Newton made great contributions not only to mechanics, but also to other aspects. In mathematics, he discovered binomial theorem and founded calculus. In optics, the dispersion experiment of solar light is carried out, which proves that white light is composed of monochromatic light. Studied the color theory and invented reflecting telescope.

2.[ Name] Albert Einstein (Jewish theoretical physicist)

When Einstein was a child, the teacher asked the students to make handicrafts, and everyone did well. Only Einstein took out an ugly little bench. Teachers and classmates laughed at him and said, is there an uglier bench in the world? Einstein said yes, and really took out two uglier ones. He said that although the first bench was ugly, it was much better than the last two.

Einstein has made outstanding contributions to photoelectric effect and relativity, and his research results on Brownian motion have become the most popular foundation of financial mathematics because of his regular grasp of a large number of disorderly factors. The concept of laser stimulated radiation put forward by him is widely used today after decades; The EPR paradox put forward in his argument with Bohr is still a topic of constant discussion in theoretical physics and philosophy of science. ...

3. Archimedes

There is such an interesting story about Archimedes. According to legend, King Guhennon of Silas asked craftsmen to make him a pure gold crown. When it was finished, the king suspected that the craftsman had mixed a fake gold crown, but the gold crown was as heavy as the pure gold originally given to the goldsmith. Did the craftsman play tricks? The problem of trying to test the authenticity without destroying the crown not only stumped the king, but also made the ministers look at each other.

Later, the king asked Archimedes to test it. At first Archimedes was also thinking hard, to the point. One day, he went to the bathhouse to take a bath. Sitting in the bathhouse, he saw the water overflowing and felt his body being gently pulled up. He suddenly realized that the proportion of gold crowns can be determined by measuring the displacement of solids in water. He jumped out of the bathtub excitedly and ran out without even considering his clothes, shouting "found it!" Eureka! " . Fureka means "I know".

After further experiments, he came to the palace. He put the crown and pure gold with the same weight in two jars filled with water, and compared the water overflowing from the two jars, and found that the jar with the crown overflowed more water than the other jar. This shows that the volume of the crown is larger than that of pure gold with the same weight, so it proves that other metals are mixed in the crown.

He is a physicist and mathematician, the founder of statics and hydrostatics.

4. Qian Xuesen

After Qian Xuesen came back, Americans became angry, kept him under strict supervision and even punished him.

The Americans once gave Qian Xuesen a trumped-up charge, told him to go to a desert island and tortured him with various punishments. It is said that he lost 50 Jin in half a year. However, Qian Xuesen's determination to return to China has never wavered. Americans say that as long as Qian Xuesen is willing to stay in the United States and not return home, he will be given the best facilities, a better life and greater honor.

Qian Xuesen (191.12.11-) is a scientist in the fields of applied mechanics, aerospace technology and systems engineering. Born in Shanghai, ancestral home in Hangzhou, Zhejiang. 1934 graduated from Shanghai Jiaotong University. 1936 received a master's degree from MIT. 1938 received his doctorate from California Institute of Technology. 1955 returned to China. He used to be the chairman and honorary chairman of China theoretical and applied mechanics Society, China Automation Society, China Systems Engineering Society and China Aerospace Society. He is currently a researcher at the National Defense Science, Technology and Industry Committee. In his early years, he did pioneering work in many fields of applied mechanics and rocket and missile technology. Many theories put forward by independent research and cooperation with von Carmen have laid the foundation for the development of applied mechanics, aviation engineering and rocket and missile technology. After returning to China, he served as the technical director of rocket, missile and satellite development for a long time, and made outstanding contributions to the establishment and development of China's missile and space industry. Creative research has been made in many theoretical fields, such as engineering cybernetics, systems engineering and systems science, thinking science and humanities, Marxist philosophy and so on, and great contributions have been made. 1956 won the first prize of Natural Science Award of China Academy of Sciences; 1985 won the national special prize for scientific and technological progress; 199 1 was awarded the honorary title of "National Outstanding Contribution Scientist" and the first-class English Model Medal by the State Council and the Central Military Commission. Academician of China Academy of Sciences. 1994 was elected as an academician of China Academy of Engineering.

5. Maxwell

Maxwell has a strong thirst for knowledge and imagination since he was a child, and likes to think and ask questions. It is said that when he was more than two years old.

Wait, once his father took him to the street and saw a carriage parked by the side of the road. He asked, "Dad, why doesn't the carriage go?"

And then what? "Father said," It's resting. " Maxwell asked again, "Why does it rest?" Father casually said 1

Sentence: "Probably tired?" "No," Maxwell said seriously, "it's a stomachache!" Another time, menstruation.

Brought Maxwell a basket of apples, and he kept asking, "Why is this apple red?" Aunt doesn't know how to answer.

, just tell him to play with blowing soap bubbles. Who knows that when he was blowing soap bubbles, he saw the colorful colors on the soap bubbles and asked.

There are more questions. When he was in middle school, he also mentioned such things as "why dead beetles don't conduct electricity" and "live cats rub against live dogs"

Will it generate electricity? "My father taught Maxwell geometry and algebra very early. After middle school, mathematics knowledge in textbooks

Maxwell knows almost everything, so his father often gives him a "small stove" and takes some difficult problems to school to do.

. Whenever the students have fun, Maxwell enters the paradise of mathematics, and he often hides in teaching alone.

In the corner of the room, or sitting alone in the shade, thinking and calculating mathematical problems with fascination.

Maxwell is mainly engaged in electromagnetic theory, molecular physics, statistical physics, optics, mechanics and elasticity theory. In particular, his electromagnetic field theory, which unifies electricity, magnetism and light, is the most brilliant achievement of the development of physics in the19th century and one of the greatest complexes in the history of science.

6. Faraday

Faraday 179 1 was born in a blacksmith's family in Newtown, Surrey on September 22nd. 13 years old, working as an apprentice in a bookstore, delivering newspapers and binding books. He has a strong thirst for knowledge and tries to greedily read all the books he has bound from the beginning by squeezing out all the rest time. After reading it, I copied down the illustrations and made my reading notes neatly. Using some simple instruments to do experiments according to books, and carefully observing and analyzing the experimental results, I turned my attic into a small laboratory. After eight years in this bookstore, he forgot all about eating and sleeping and studied hungrily. When he later recalled this life, he said, "I began to look for my philosophy from these books after work. Two of these books are particularly helpful to me. One is the Encyclopedia Britannica, from which I first got the concept of electricity. The other is Mrs. Messi's chemical dialogue, which gave me the scientific basis for this course. "

Faraday is mainly engaged in the research of electricity, magnetism, magneto-optic and electrochemistry, and has made a series of important discoveries in these fields. After Oster discovered the magnetic effect of current in 1820, Faraday put forward the bold idea of "generating electricity by magnetism" in 182 1 and began a hard exploration. 182 1 September, he found that the electrified wire can rotate around the magnet, and the magnet moves around the current-carrying conductor, which realized the transformation from electromagnetic motion to mechanical motion for the first time, thus establishing the laboratory model of the motor. Then, after numerous experiments failed, the law of electromagnetic induction was finally discovered at 183 1. This epoch-making great discovery has enabled mankind to master the methods of mutual transformation of electromagnetic motion and mutual transformation of mechanical energy and electrical energy, and has become the basis of modern generator, motor and transformer technology.

7. Galileo

Once, he stood in the Catholic church in Pisa, staring at the ceiling, motionless. What is he doing? It turned out that he followed the pulse of his left hand with his right hand and looked at the light swinging back and forth on the ceiling. He found that although the swing of the lamp is getting weaker and weaker, the distance of each swing is gradually shortened, but the time required for each swing is the same. So Galileo made a pendulum with a suitable length to measure the speed and uniformity of the pulse. From here, he discovered the law of pendulum. This clock is made according to the law he discovered.

Main contribution

1, contribution to mechanics

1. 1 describes the movement scientifically.

Scholastic philosophers mainly pay attention to the "ultimate cause", so they make a causal and qualitative description of movement with the help of vague concepts such as matter, form, purpose and natural position, and divide movement into natural movement and forced movement. Galileo believed that this description and classification method actually led the study of sports into a desperate situation. He doesn't believe in the difference between natural movement and forced movement, and thinks that movement should be classified according to the basic characteristic quantity of movement-speed, and thus puts forward.

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.

1.2 establish the law of falling body

Through Galileo's conclusion, this law must be established in the limit of free fall. The above results can be expressed in another mathematical form, that is, the total distance traveled by a sphere in a certain period of time is proportional to the square of this period of time, or expressed by Galileo himself.

1.3 determining the law of inertia

Law of inertia: Uniform motion and stillness are eternal, because they are not imposed. It is this eternal movement that maintains the order of the earth and the whole universe. Galileo also clearly pointed out that the speed of an object does not need external force to maintain, but external force can change the speed of an object, that is, it produces acceleration, which frees people from Aristotle's fallacy that "force is the reason to maintain the motion of an object", thus leading the research of dynamics to the right direction.

1.4 study projectile motion

When studying throwing objects, Galileo proved that a flat throwing object can be decomposed into two kinds of movements: horizontal falling and vertical falling. He proved that under the same initial velocity of projectile, when the projectile angle is 45 degrees, the range is the longest.

1.5 puts forward the principle of relativity.

Galileo continued in the Dialogue: "As a movement, movement works as a movement, but only for objects without such movement. In all objects with equal motion, motion does not work, as if it does not exist. " Galileo said this when he demonstrated that people on the earth could not perceive the motion of the earth, so what he called "motion" was naturally uniform motion. A system with uniform motion is a system in which the law of inertia can be established, so it is also an inertial system. Galileo's words brilliantly expounded the principle of relativity: all mechanical experiments done in inertial system can't prove the motion of the system itself.

1.6 pioneered scientific research methods.

Galileo's research on the theory of motion adopted a very effective procedure for the development of modern science, that is, generally observing phenomena → putting forward working hypotheses → drawing special inferences by mathematical and logical methods → testing inferences through physical experiments → revising and popularizing hypotheses, and so on.

2. Contribution to astronomy

Galileo's decisive role in spreading and defending Copernican astronomy.

1543, the Polish astronomer Copernicus published his immortal book "The Theory of Celestial Motion" and established the Heliocentrism. The establishment of this theory is an epoch-making event in the history of science and marks the beginning of modern science. But this theory did not attract widespread attention at that time. After the spread of Bruno, especially Galileo, the situation has been very different. 1609, Galileo used his telescope with a magnification of 0 times to observe every day, and saw the sunspots on the sun, the uneven surface of the moon, the four satellites on Jupiter, the gains and losses on Venus, and so on. These results directly and indirectly prove the correctness of Copernicus' theory.

3. Contribution of scientific experimental methods

The so-called scientific experiment is a scientific activity that people artificially control, simulate, create or purify a natural phenomenon process, eliminate interference, highlight the main factors, and study the laws of nature under favorable conditions. In Galileo's scientific career, he not only emphasized the importance of observation and experiment, but also emphasized the equal importance of reason and experience. On the basis of experience, he realized the understanding of objective nature through rational mathematical construction. Galileo spent his whole life.

Thanks to Galileo's fruitful work and incisive scientific thought, the scientific experiment method has developed to a complete level.

A brand-new height has put physics on the road of real science and opened up broad prospects for the systematic and all-round development of modern natural science. Galileo combined theory and experiment closely and harmoniously, and formed a set of scientific research methods. It has effectively promoted the development of modern science. It is this new method-the combination of logical reasoning and scientific experiments-that makes physics get rid of the situation of relying on metaphysical speculation, self-awareness, speculation and qualitative discussion and embark on a solid scientific road. Although Galileo did not regard experiment as the only fulcrum of theory, it changed the nature and direction of science. It is in this sense that Galileo is called the founder of scientific experimental method and the founder of modern science. Einstein.

The book Evolution of Physics once commented: "Galileo's discovery and the mathematical reasoning method he applied are one of the greatest achievements in the history of human thought, marking the real beginning of physics." This evaluation still has profound lessons for us.

4. Contribution to philosophy

Throughout his life, he insisted on fighting against idealism and scholasticism of the church, advocated understanding the laws of nature with concrete experiments, and believed that experience was the source of rational 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.

8. Joule

Joule, a famous British scientist, loved physics since he was a child. He often does some experiments about electricity and heat by himself.

One holiday, Joule and his brother traveled to the suburbs. Joule, who is clever and studious, never forgets to do his physics experiments even when he is playing.

He found a lame horse, led by his brother, and quietly hid behind him. He used a volt battery to electrify the horse, trying to see how the animals reacted after being stimulated by the current. As a result, the reaction he wanted to see appeared. The horse jumped wildly after being shocked and almost kicked its younger brother.

Although the danger has appeared, it has not affected the mood of little Joule who loves to do experiments. He rowed with giggle to the lake surrounded by mountains, where Joule wanted to try the echo. They filled the musket with gunpowder and then pulled the trigger. Who knows "bang", a long flame spouted from the muzzle and burned Joule's eyebrows, almost scaring my brother into the lake.

At this time, the sky was covered with thick clouds, lightning and thunder. Joule, who just wanted to go ashore to take shelter from the rain, found that it took a long time to hear the thunder after every lightning. What happened?

Joule didn't take shelter from the rain, dragging his brother up a hill and carefully recording the time of lightning and thunder with his pocket watch.

After school started, Joule almost wanted to tell the teacher all the experiments he had done and ask for advice from the teacher.

The teacher smiled at Joule, who was eager to learn and curious, and patiently explained to him: "The speed and harmony of light are different. The speed of light is fast and the speed of sound is slow, so people always want to see lightning before hearing thunder, but in fact lightning and thunder happen at the same time. "

Joule suddenly realized. Since then, he has been more fascinated by learning scientific knowledge. Through continuous study and careful observation and calculation, he finally discovered the mechanical equivalence of heat and the law of conservation of energy, and became an excellent scientist.

Joule has been engaged in experimental research all his life and made outstanding contributions to electromagnetism, heat and gas molecular dynamics theory. He became a physicist through self-study.