The craftsmen of the Ming Dynasty were tired of playing with electric sparks, so they made further requests to Sun Yi if Li De Ye could give a better electric measuring tool. Pen? Interesting? Pavilion wWw. ｂiquge。 ｉｎfo

Sun Yi decided to make one.

The ammeter of later generations could not avoid electromagnetic induction, so Sun Yi decided to start with magnets.

Sun Yi found a few iron rods five or six inches long from the blacksmith—the ordinary raw material for drawing iron wires, and a "soft iron" rod.

The people of the Ming Dynasty called soft iron "soft iron", which is actually iron with relatively low carbon content.

Sun Yi himself took a "soft iron" stick and gave the ox blacksmith an ordinary iron rod and asked him to learn to do it together in his own way.

Sun Yi first dipped a gypsum gauze in water and wrapped a layer on the outside of the iron rod to make a plaster shell.

With the brass wire that catches the rabbit, two of them are placed in a row, and they are tightly wrapped around the plaster shell from head to tail with their fingers.

After untying one of the copper wires, Sun Yi got a dense and consistent brass coil.

Brush the void of the brass coil with wet plaster, and wait for the plaster to solidify, and the coil will be fixed to ensure that there will be no short circuit between the turns of the coil.

And that's just the first layer.

Wrap the outside of the first layer with plaster gauze, and do the same for the second layer.

After a few layers, the originally slender iron rods in the hands of Sun Yi and the blacksmith turned into thick pillars.

In Sun Yi's eyes, these are two "fat" electromagnets.

Without a suitable insulated wire, Sun Yi could only use this "stupid method"

Brass wire is used instead of "pure copper coin" wire, first, because it is relatively hard and will not be deformed casually; The second is because brass has a larger resistance than "pure copper", and the coil itself is still a resistor, which will not be short-circuited and burn the battery.

Connecting the two electromagnets to the circuit, sure enough, they both showed super magnetic force. Hand the remaining few iron rods up, "snap" the ground, and you can be firmly sucked by the electromagnet, and if you want to pull it off, you have to work hard.

The ox blacksmith is accustomed to seeing magnets. Magnetite is the raw material for ironmaking, and when making ironware, there are often tools that can absorb iron inexplicably. But with such a strong suction, the ox blacksmith is still the first time to see him.

Sun Yi lost the power. The iron rod that was sucked on Sun Yi's "soft iron" rod immediately fell off. And the ordinary iron rod that was sucked on the electromagnet of the ox blacksmith seemed to hesitate for a moment, and struggled on the electromagnet of the cow blacksmith for a while before it reluctantly fell off.

Sun Yi grabbed the fine iron filings and tried them on the two electromagnets that had been cut off. The iron rod of the ox blacksmith was immediately filled with iron filings, while Sun Yi's "soft iron rod" was only sparsely stained with a thin layer.

The people of the Ming Dynasty all looked at Sun Yi, clearly wanting an explanation.

Sun Yi explained: "The electricity that flowed around the iron rod just now turned the iron rod into a magnet. Although the electricity is cut off now, the iron rod in the hand of the ox blacksmith is hard magnetic, and there is residual magnetism, while the soft iron in my hand is soft magnetic, and as soon as the electricity is withdrawn, the magnetism is basically gone. Now, let's make a few magnets using the hard magnetism of ordinary iron rods. ”

Sun Yi threw all the remaining iron rods into the fire and heated them, and according to Sun Yi's idea, they had to be heated until the Curie temperature of the iron was 770 degrees.

The so-called Curie temperature was discovered by Marie Curie's husband, Mr. Curie. Above this temperature, the magnet will demagnetize. This is because small atomic-level magnets that are originally arranged inside the magnet will become disorganized above this temperature.

Sun Yi couldn't measure the temperature of the iron rod, so he could only guess, in other words, an ordinary furnace fire, burned casually, the highest was 1,000 degrees Celsius, and the iron rod couldn't be burned anyway.

Sun Yi instructed the ox blacksmith to take out an iron rod and stick it vertically into the ground, while at the same time using a hammer to keep striking the iron rod. Connect an electromagnet and put the core of the electromagnet and the iron rod head to head. Then turn on the second electromagnet and put it on the butt of the first electromagnet.

Sun Yi used the influence of Curie temperature in reverse.

The iron rods are heated first, freeing up the small magnets at the atomic level, allowing them to rotate freely. It's like heating up the chilli oil in the refrigerator, and the chili noodles in the oil start to move.

Under the combined force of two powerful electromagnets, the atomic-level small magnets in the iron rod turned around and lined up, keeping their direction consistent with the general environment.

The ox blacksmith kept striking the iron rods, just to shake the atomic magnets so that they could turn around.

As the temperature of the iron rod decreases, the iron rod hardens, and the formation of the atomic magnet is "frozen".

In this case, even if the applied magnetic field is removed, the iron rod will exhibit strong magnetism. So the ordinary iron rod became a magnet rod.

The blacksmith picked up the magnet rod that had been made, poked it into the iron filings, and when he took it out again, the magnet rod had turned into a "hairy chestnut". Approaching the ordinary iron rod with a magnet rod, before it could touch it, the ordinary iron rod rolled over with a whirl, and then snapped and pasted up. "It's not small!" , the bull blacksmith commented.

According to this method, several people processed the iron rods into magnets.

The regular shape of the magnet rod makes the characteristics of magnets attract opposites and repel the same sex.

Sun drew the magnet sticks into a long stick and made a few chalk strokes on the head of each magnet.

Then tie the center of the magnet with a thin wire, and several people ran to the distance, hung down the magnet, and found that the chalk marked the South Pole.

At the end of the Ming Dynasty in the fifth year of Chongzhen, the compass should have become popular, and Sun Yi asked the people of the Ming Dynasty around him, "Do you know why magnets point north and south?" ”

Jia Daoshi didn't think about it, and immediately replied: "Magnets belong to gold, gold gives birth to water, and the north belongs to water, so the water of the north is the son of magnets. Magnets are born from magnets, and magnets are born from yang energy, which is fire, located in the south, so the south is equivalent to the mother of magnets. The magnet should not only favor the mother but also cherish the children, so it is natural to point in the north-south direction. ”

The theory of Yin and Yang and the Five Elements of Jia Daoshi these days is quite popular among craftsmen. But with such a complicated blood relationship, Sun Yi estimated that Daoist Jia should not be able to figure it out by himself.

Sun Yi asked, "Did you come up with this answer?" ”

Jia Daoshi hurriedly waved his hand, "This is the wisdom of the ancients, and it was concluded hundreds of years ago. ”

Sun Yiyi nodded: "Our magnet is not a magnet, it's electricity!" ”

Jia Daoshi felt that the whole person was not good at that time.

——In modern terms: the three views are shattered.

"The magnet of the lord is born of electricity, and electricity is born of gold,......, the humanity of this loving mother and child is all messed up!"

Sun Yi looked at Daoist Jia's dejected appearance, and felt very sympathetic to him in his heart. Because, Sun Yi himself has experienced a similar shattering of the three views, and knows the torment of the collapse of that kind of faith. And what caused Sun Yi to destroy the three views was still a magnet.

Sun Yi knew from a young age that China has a vast land and a long history, and has four major inventions. The oldest of the four great inventions is the compass, which dates back to the Warring States period, when the compass was called "Sinan", a bronze compass with a natural magnet polished spoon. Sinan's photographs have appeared in countless textbooks and reading materials, and the historical museum preserves the Sinan's model restored by modern scientists based on ancient documents.

It wasn't until he was in college that Sun Yi learned about magnetic materials, knew hard and soft magnetism, and could calculate magnetic flux, that he learned that natural magnets in nature have very weak magnetic forces. Sun Yi couldn't help but wonder, such a simple and heavy natural magnetic spoon could actually be guided? And the natural magnet is afraid of vibration, afraid of high temperature, when the natural magnet is made into a spoon, the vibration during the processing will demagnetize it, and the high temperature generated by the polishing during the processing process will make it completely demagnetized.

Digging deeper, Sun Yi found that the so-called ancient documents are the twelve words of Wang Chong's "On Heng and Shi Ying" in the Eastern Han Dynasty.

And China, Sinan has never been unearthed.

Digging deeper, Sun Yi found that in 1952, Academician Qian Linzhao, who was engaged in metal physics research at the Institute of Physics of the Chinese Academy of Sciences, received a task that Guo Mo, president of the Chinese Academy of Sciences, needed to bring a gift symbolizing Chinese civilization to the Soviet Union if he wanted to visit the Soviet Union. The gift was determined to be an imitation of a set of "Sinan" representing the achievements of ancient Chinese science.

Academician Qian found the best magnet, and went to the best glaze factory in Beijing to find jade workers to help him ponder, according to the plan provided by Wang Zhenduo, director of the Museum Division of the Cultural Relics Bureau of the Central Ministry of Culture, the master of the glaze factory took the shape of the spoon of the Han Dynasty, carved out a beautiful natural magnet artifact.

This magnetic spoon is placed in the center of a fine bronze site, a divination tool of the Eastern Han Dynasty, surrounded by a total of 24 directions engraved with four dimensions, eight stems and twelve earthly branches. The central part of the site was polished to a smooth finish, but after trial and error, the "Sinan" made of this natural magnet just couldn't guide.

However, the day of Guo Moruo's visit is getting closer and closer, so he can only use an electromagnetic coil to magnetize the magnetic spoon, just like Sun Yi just did, so that the magnetic force of the spoon itself is large enough to resist the friction when the spoon rotates.

In fact, Sinan's spoon model was only speculated by Chinese scholars in the 193s and 40s.

The first person to restore the spoon Sinan was Wang Zhenduo, an expert in the restoration of Chinese ancient cultural relics.

In October 1945, Wang Zhenduo made a preliminary test on the glass sphere with tungsten steel artificial magnet and artificial magnet natural magnet in Lizhuang, Chongqing.

In August 1947, Wang Zhenduo further restored the spoon-shaped sinan with a natural magnet in Nanjing.

His conclusions were published in the third volume of the Chinese Journal of Archaeology, "Sinan Compass and Compass Plate".

In the supplement at the back of the text, he said: "The preliminary experiment of Sinan in the first part of the article, for the completion of the rear of Sichuan and Yunnan, this summer to work in Beiping, in the face of the magnet purchased from Cixian County, the ore surface is mixed with garnet, the small pieces are still pure, and magnetic, please jade workers still wash the machine for Sinan, to the construction procedures, more simple than the solution of jadeite, and easy to break, believe that its hardness is lower than jadeite. In the construction experiment, and get a valuable proof, for the natural magnetic magnet, with the washing machine to shape the spoon-shaped Sinan, its magnetism does not completely disappear due to the construction procedures of the washing machine, and theoretically must be reduced due to the linkage friction of the washing machine, this spoon-shaped Sinan, unfortunately there is no appropriate amount of magnetic instruments, with the measurement of its magnetism, but we get a conclusion through the records before and after the construction: the natural magnetic magnet along its north and south poles, and the old Chinese method of jade washing machine to cut the long for the south, placed on the site to turn it, It is still endowed with strong magnetism, because it still has the performance of polarity, and its spoon head guide is fully compatible with the function of the performance of Sinan made by artificial magnet magnetism mentioned above, so according to the experimental inference of the method of Sinan made by the ancients, the natural magnet is the most direct and simple. ”

It is a pity that in 1947, Wang Zhenduo claimed that the direct and simple method was not made by Academician Qian and Dean Guo according to the plan provided by him in 1952!

Some people in the physics community have always stood up to question the spoon-shaped Sinan, the late Professor Liu Bingzheng of the School of Physics of Northeast Normal University questioned Sinan from 1956, he found seven different kinds of natural magnets, not only did a large number of physical experiments to prove that natural magnets can not be as good as the Sinans on display, and until his death in 2006, he still published papers from all aspects to express that Sinan is not a spoon-shaped magnet.

In fact, the fact that the magnet was charged with an artificial magnetic field in 1952 is not a secret inside. At the end of the 80s of the 20th century, the Chinese History Museum confirmed that the "Sinan" model was a wrong concept, and at the end of the 90s, the Sinan model was no longer displayed to the public.

In 2005, Sun Jijin, a researcher at the National Museum of China, determined that the word "ladle" in "Sinan Zhilao" was actually "discretion" and had nothing to do with the spoon based on the remnants of the Song book "On Heng" in the former Beiping History Museum.

Contemporary archaeologists even advocate that Sinan is actually a mechanical guide car.

Some scholars believe that Sinan is actually the Big Dipper.

However, in 1952, the artificially magnetized Sinan model was sent to the Soviet Union as a symbol of ancient Chinese civilization.

In 1953, China Post issued a set of special stamps "The Great Motherland", the fourth group of "Ancient Inventions" a total of four, of which the first (special 7.4-1) is this spoon-shaped "Sinan". The caption reads "Sinan. Guide Instruments. Warring States (3rd century B.C.)", face value 800 yen.

With the "Four Great Inventions" written into history textbooks, generations of Chinese students have come to know this spoon-shaped "Sinan". This "Sinan" has also been repeatedly given to international friends. However, whether it is the period of the Chinese History Museum or the era of the National Museum of China, the "Sinan" model collected and exhibited is tungsten steel magnetized by electromagnetic fields.

In 2002, the model of the spoon-shaped "Sinan" was placed at the South Pole.

In 2008, the spoon-shaped "Sinan" appeared at the opening ceremony of the Olympic Games.

What made Sun Yisanguan collapse was not whether Sinan was a magnet, a guide car or a Big Dipper; But it is an inconclusive thing, how can it be written into a primary school textbook? If it weren't for Sun Yi's major in science and engineering, Sun Yi would have firmly believed that everything in his textbooks when he was a child would have been until he died.

Therefore, Sun Yi patted Daoist Jia's shoulder and said sympathetically:

"The water here is very deep, and you can't figure it out for a while, you must have to struggle for a while, and it's good to pass."

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References (not related to the plot, skip for uninterested readers)

(Only list historical facts, do not associate, do not comment)

The "Four Great Inventions" Earth Motion Instrument and Wang Zhenduo Model

Wang Zhenduo (1911-1992), whose name is Tianmu, was born in Baoding, Hebei. The existing Sinan, the guide car, the Jili drum car, the wind and ground motion instrument, and the water transport instrument elephant platform are actually Wang Zhenduo's restoration models.

Author:

"Research and Model of the Drum Car in the Guide Car Record"

Sinan Compass and Compass Disc - Discoveries and Inventions of Ancient Chinese Knowledge of Magnetostatics

Uncovering the Secret of China's "Astronomical Clock" - A Brief Introduction to the Restoration of the Song Dynasty Water Transport Instrument Statue

Research on the Restoration of Zhang Heng Waiting Wind and Ground Motion Instrument

Wang Zhenduo studied at the Department of History of the Graduate School of Yenching University in 1934~1936.

In 1936, Wang Zhenduo published an article entitled "Speculation on the Construction Method of the Han Zhangheng Waiting Wind and Ground Motion Instrument" in the 20th issue of the Yenching Journal, and hand-drew a set of internal and external structural drawings as the accompanying drawings of the paper. In the drawings, he designed the shape according to the record of "resembling a wine bottle" in the "Book of the Later Han Dynasty: The Biography of Zhang Heng", but for the internal structure, since there are only 196 characters in the historical materials, he followed the structural principle of "hanging pendulum": that is, a pendulum hangs down from the upper part to determine the direction of the earthquake.

In 1937, the Japanese seismologist Hagiwara Sonri also released his restored paper on Zhang Heng's geodynamic instrument. Unlike Wang Zhenduo, Hagiwara Sonri proposed the principle of the upright pole, that is, in the middle of the geodynamic instrument, an inverted pole is placed, and in the event of an earthquake, the pole falls, thus triggering the corresponding mechanism.

In 1949, Wang Zhenduo served as the director of the Museum Division of the Cultural Relics Bureau of the Ministry of Culture. Wang Zhenduo received the national task to restore Zhang Heng's geodynamic instrument and Sinan in the "Four Great Inventions".

In 1951, according to the record of "Zhongdu Zhu" in the Book of the Later Han Dynasty and drawing on the principle of the upright pole of Hagiwara Zunli, Wang Zhenduo designed and restored a 1:10 scale wooden model of the "Zhang Heng Geokinetic Instrument", which was subsequently collected in the Chinese History Museum. It has been exhibited abroad several times in more than half a century. As the embodiment of human civilization, it is placed at the headquarters of the United Nations World Intellectual Property Organization, and alongside it is the rocks that the Americans brought back from the moon.

The April 1952 issue of the People's Pictorial took "The Ancient Scientific Invention of the Great Motherland to Explain the Structure and Working Principle of the Geodynamic Instrument" to the readers. At the end of the article, a paragraph reads: "The model introduced here was designed and completed by us in 1951, and is mainly reproduced based on the records of the Book of the Later Han Dynasty and the Biography of Zhang Heng, as well as archaeological materials. ”

In 1953, China Post issued a set of special stamps "Great Motherland", the fourth group of "Ancient Inventions" a total of four, the first one is Sinan, the second is the geodynamic instrument, the third is the drum car in the memory, and the fourth is the armillary sphere. The second of them (Special 7.4-2) is a model of the geodynamic instrument, and the caption text is "Geokinetic instrument. Recording seismic instruments. Eastern Han Dynasty (A.D. 132)", face value 800 yuan.

Since then, the "Four Great Inventions" have been written into primary and secondary school textbooks, and in previous textbook revisions, they have not mentioned that these are actually restored by later generations according to their own understanding. Generations of teachers and students have thought that the pictures in the textbooks are Zhang Heng's geodynamic instruments of the year. The China Earthquake Administration used this restoration model to mark it for decades.

According to the upright pole principle of "Zhang Heng Geodynamic Instrument", the upside-down beer bottle is used as an alarm during an earthquake, which is widely respected by Chinese.

However, Chinese and foreign seismologists believe that the "upright rod model" has made a mistake in principle. Since the 1960s, the earthquake circles at home and abroad have been sharply criticizing Wang Zhenduo's model, believing that the "upside-down beer bottle" is even more misleading!

In 1972, the Japanese scholar Sekino Yu used calculations to deny the principle of the upright pole.

On July 28, 1976, an earthquake measuring 7.8 on the Richter scale occurred in Tangshan, and the "Zhang Heng Geodynamic Instrument" 160 kilometers away did not respond.

In 1976, Academician Fu Chengyi, the founder of seismology in China, pointed out the errors in principle of Wang Zhenduo's 1951 model. Fu Chengyi said that the hanging pieces of meat under the beams are stronger than your model.

In 1983, Sleiswick of the Netherlands and Sevi of the United States proposed that Wang's model could not be established.

In 1988, "Zhang Heng's Geodynamic Instrument" visited Nara, Japan, and the Chinese commentator explained that when explaining the working conditions of the seismograph to the Japanese audience, he held a wooden stick and poked it with a wooden stick, and the copper pill in the dragon's mouth would fall into the mouth of the frog below. This scene was photographed, and the "immovable ground motion instrument" stung many people.

Feng Rui, a professor at the Chinese Academy of Sciences, said, "Mr. Wang Zhenduo's model has been proven to be a wrong model, and it must be discarded ,......, only for ornamental value." ”

In 2003, Professor Feng Rui cooperated with other institutions to restore the "Zhang Heng Geodynamic Instrument".

On September 20, 2009, the new hall of the China Science and Technology Museum was opened, and the new earth motion instrument met the audience in the new hall.

At this time, the national primary and secondary school textbooks still talked about the "upright rod" theory of inverting beer bottles for 60 years.

In the fall of 2010, after the introduction of the Ministry of Education's education reform, according to the syllabus, "Zhang Heng's Earth Movement Instrument" is no longer the content of history textbooks.