Fang Yizhi was ordered to come to the audience, and he also brought his three sons, ten-year-old Fang Zhongde, eight-year-old Fang Zhongtong, and four-year-old Fang Zhongxu.

"Meet Your Majesty!"

Three children, with their father, upright.

Zhao Han liked it very much, and after teaching on the spot, he called his children as well.

The eldest son Zhao Kuanghuan is six years old, the second son Zhao Kuangwei, the eldest daughter Zhao Furong, and the second daughter Zhao Hanjin are all only three years old.

A few children went to play by themselves, and Zhao Han asked casually, "What are the recent results of physics research?" ”

Fang Yizhi replied: "Back to Your Majesty, the minister found that gravity has nothing to do with the mass of the object. A pound of iron, a ten-pound piece of iron, ignoring the subtle air resistance, they fall from a height and hit the ground at the same time. ”

"It was an amazing discovery." Zhao Han said with a smile.

Half a century ago, Galileo Galilei had discovered that the Leaning Tower of Pisa had two iron balls falling at the same time.

It's just that Galileo didn't know gravity, and the gravitation on China's side was still a concept given by Zhao Han.

Zhao Han asked again: "What about the other than that?" ”

Fang Yizhi replied: "There is a student who put forward a very outrageous hypothesis that water can freeze, water can be heated and boiled into steam, and iron can be heated and turned into molten iron. That is, everything has a real state, a water state, and a gaseous state. Ice is solid, heated and melted into water, and then heated and transpirated into gas. Iron is the real state, which is heated and melted into molten iron, and then heated and rises into iron gas. ”

Zhao Han smiled: "Has he verified his hypothesis?" ”

Fang Yizhi said: "Many experiments have been done, and some items echo its hypothesis. But other objects, such as steel, simply cannot rise to gas. There is also wood, which burns when it is burned with fire, and when it is fried in a pan, it will be hot and black like charcoal. ”

Zhao Han said: "What do you think of his hypothesis? ”

Fang Yizhi replied: "The minister thinks it should be correct. Molten iron cannot be transpired into gas, probably because the heating is not enough. As for the wood...... I don't have a clue yet. ”

"Is it possible, the real state, the water state and the gaseous state, it must be a pure substance," Zhao Han said in an orderly manner, "Salt water is also water, but mixed with salt." After boiling the salt water, the water is gone, and all that is left is salt, which is how the salt boiling method comes from. Therefore, salt water is not pure water. And then there is the wood, the fresh wood has moisture, and it becomes lighter when baked or dried, because the moisture in the wood has evaporated. If it is reheated and burned, it will become charcoal, and something must have changed? ”

Fang Yizhi pondered, but he still couldn't figure it out.

Zhao Han reminded: "It's better to make a thermometer. ”

"What is a thermometer?" Fang Yizhi asked.

Zhao Han said: "Clocks have scales that can record time. The scale rod has a scale to weigh the weight. Why not build a tool for measuring heat and cold? ”

The more Fang Yizhi thought about it, the more confused he became: "The water temperature can be measured by hand, how to measure it with tools?" ”

Zhao Han smiled: "Have you noticed that if you put a bucket of water outside in winter, the volume will become smaller after freezing?" Or a door that can be easily closed in the winter only to hit the door frame in the summer? ”

Fang Yizhi thought about it carefully: "That's really the case. ”

"My guess is that everything has the phenomenon of thermal expansion and cold contraction," Zhao Han said, "It is better to make a utensil out of glass, pour mercury into it, and then mark the corresponding scale." When placed in hot water, the height of the mercury column is different, and when placed in cold water, the height of the mercury column is different. The water that is about to freeze is set to zero degrees and marked on the thermometer. Then set the temperature of the water that is about to boil to 100 degrees. In this way, from zero to 100 degrees, it is divided into 100 scales, and you can know what each degree is, and you can measure the heat and cold of various objects. ”

Fang Yizhi began to think again.

Zhao Han continued: "The heat transfer of the glass is inconvenient, so you can make a contact pin in the thermometer and connect the mercury inside, and use copper as the contact pin of the thermometer. ”

At this point, Fang Yizhi was restless, obviously wanting to go home immediately to do the experiment.

Because the amount of information is too large, we must first prove the principle of "thermal expansion and cold contraction".

Thermal expansion and cold contraction, only four words, but it is the key for mankind to enter the steam age.

In more than 50 years, the first model of a steam engine will be born in Europe. Nineteen years later, the first steam water lifter appeared, which discharged water from the mine through a steam engine.

Seeing that Fang Yizhi's mind was no longer here, Zhao Han smiled and said, "Go and experiment, my three sons, I will send someone back." ”

"Wechen retires!" Fang Yizhi immediately got up.

In the garden.

A few children were playing with bamboo dragonflies, and Fang Zhongde, who was fourth in the Jinling Mansion unified examination, put his palms together, and the bamboo dragonflies immediately jumped up to the sky.

"Wow, flying so high!"

The princes and princesses craned their necks, their eyes moving with the flight trajectory of the bamboo dragonfly.

When the bamboo dragonfly hit the ground, the dragon picked it up and said, "Are these its wings?" How does it fly? ”

Fang Zhongtong held his head high and said: "My father taught that the blades of bamboo dragonflies have an inclination angle, and when they rotate, they push the air downwards and at the same time obtain the reaction lifting force of the air. ”

Gong'er didn't understand at all, but she still admired: "Your father is so smart, my father doesn't understand!" ”

Zhao Han stood next to him, and suddenly couldn't cry or laugh.

A bamboo dragonfly, several children rushed to play, Zhao Han asked the female officer to bring a piece of kraft paper, fold it into a paper airplane and fly out vigorously.

"This is fun too!" Gun'er rushed over with her younger siblings.

Fang Zhongde and Fang Zhongtong brothers were puzzled: "Why can this fly?" ”

Zhao Han smiled and said, "Go home and ask your father." ”

……

Suzhou.

Wu Weiye, Liu Tongsheng and other ministers of the late Ming Dynasty were boating on Taihu Lake.

Liu Tongsheng is the champion of the Ming Dynasty, and he had already "taken refuge" in Zhao Han, and ran away with his family at night. He and Wu Weiye were both elected as princes, but after Chongzhen lay down and slackened his government, he was squeezed out by Xue Guoguan and other political enemies.

In indignation, Wu Weiye, Liu Tongsheng and others collectively resigned and returned to the south, just avoiding Li Zicheng's torture.

They have no meritorious service, so they can only start as small officials.

After all, they are all erudite and famous Confucians, and they can't pull their faces to be officials, so they simply apply for a job as a teacher in the school and teach the four books in the middle school in their hometown.

Now that it is summer vacation, Liu Tongsheng went to Jiangsu to visit friends, and brought a vote of down-and-out literati to visit Taihu Lake together.

In the painting boat, the famous prostitute Su Nuan was playing the qin.

Wu Weiye sighed: "Do you know this year's township test? ”

Chen Mingxia said in a disdainful tone: "The content of the township test is superficial. The Five Classics are not examined, only one four-book question is examined, and the children of the Ming Dynasty can easily come to it. Such a imperial examination is also a mistake for people's children! ”

This last generation of the Ming Dynasty Tanhualang, before he had time to be admitted to the Jinshi, the Ming Emperor Chongzhen had already hanged himself.

Chen Mingxia also wanted to be an official in the Datong Imperial Court, starting as a minor official, and was promoted to mayor in half a year. After working for another two or three months, I felt that there was no oil and water, and it was boring, and it was far from being a magistrate, so I simply resigned and went home to recite poetry and music.

"This is not a imperial examination," Mao Bijiang said, "This is only a provincial unified examination, and there is only one question left in the Baguwen, and the rest are all practical subjects." I heard from a friend that His Majesty had long planned to reinstate the imperial examination, but he would definitely not use the eight shares to take the scholars. ”

Jin Sheng sighed and said: "It's excellent not to take the imperial examination with eight shares, and when the imperial examination resumes one day, I will also take the exam." ”

Mao Bijiang reminded: "Then you have to learn it in advance, don't fail the exam when the time comes." ”

Jin Shengxian was born in Xiucai, and has not yet been expelled from school.

Historically, this person was dismissed from his fame, purely because he took the county school teachings to make fun of it.

One of them is an annual exam, which is equivalent to the final test exam every year, and the question is asked: Is it tempting to do so?

Jin Shengsi's article is as follows: In the empty mountains and poor valleys, there are ten thousand taels of gold; Outside the white leaves, there is a beautiful person. Is the Master tempted? Said: Move, move, move......

The priest laughed angrily and asked, "Why did you write thirty-nine movements?" ”

Jin Sheng replied with a sigh: "Confucius said that forty is not confused, and he is Chinese New Year's Eve nine years old when he is born later. ”

Later, the county learned the teachings and teachings, and gave Jin Shengxi a separate topic: What is the reason why people are different from beasts?

obviously scolded Jin Shengsian as a beast, and Jin Shengsian immediately gave a broken question: Beasts cannot be taught, even if they are taught, they are also beasts. Beasts are not to be trained, that is, to be disciplined are also beasts.

Now that the new dynasty has been established, Jin Shengsigh is also very chic.

His main job is to jump gods, and his side job is to be a literary critic, both of which are relatively profitable.

Liu Tongsheng lamented: "Alas, the imperial examination is not prosperous. I was the champion of the previous dynasty, but now I am just the king of children, teaching a group of children in the county middle school. Your Majesty, really...... What a ......."

What is it, I dare not say it.

All the scholars were disdainful in their hearts, and felt that this old gentleman was too stupid.

When the Liu family took refuge in Emperor Datong, Emperor Datong only had the territory of two counties. Absolutely from the dragon's work, I have to flee with my family, and now I can't even get an official position.

If you don't run, it is estimated that you will be a third-grade official!

In fact, Liu Tongsheng himself regretted it, but it was useless to regret it. If he really wants to choose again, he will still run away with his family when he doesn't know the future.

He is a top talent, how can he take refuge in the thief?

Wu Weiye saw that the atmosphere in the cabin was not right, and pointed to a mountain pavilion in Taihu Lake and said, "Brother Jin Qing, an epiphany pavilion was completed last year. Do you know why this pavilion has this name? ”

"A variety of epiphyllum outside the pavilion?" Liu Tongsheng asked.

"No, no," Mao Bijiang said with a smile, "At the top of this pavilion, there is a treasure bottle." The vase is hollowed out into two layers, and an oil lamp is placed in the bottle, so that the light can be seen several miles away at night. The wind blows from Taihu Lake, the four windows on the outer wall of the vase rotate, and the lights flicker on and off, like a flash in the pan. A copper plate is hung in the pavilion, sesame oil is added, and the fire of the treasure bottle will never be extinguished. Not only that, no matter how strong the lake breeze is, it can't blow out the lights in the vase. ”

This pavilion is not only a place for visitors to rest, but also a beacon for boatmen at night.

Liu Tongsheng exclaimed: "This skillful craftsman has also done it. ”

Jin Sheng sighed and said, "That craftsman is called Xu Zhengming, what a strange person. It imitates a children's toy bamboo dragonfly and makes a flying chair. After working for more than ten years, all the money earned was smashed into it, and the family often ran out of food. I finally flew last month, but I was only a little more than a foot above the ground, and I barely flew two or three feet away before I fell. ”

"Can you really get off the ground?" Liu Tongsheng was surprised.

Chen Mingxia laughed: "How tall is it called flying?" Just a plaything too. ”

(Note: The deeds of the craftsman Xu Zhengming can be found in "Wu County Chronicles, Xiangshan Xiaozhi".) The flying chair was more than a foot above the ground, flew over a stream and fell to the ground. After Xu Zhengming's death, his wife chopped the flying chair and burned it, just because she complained that her husband threw all the silver into it. ）

(Thank you for reading the book and forgetting the leader!) ）