Lu Shuren once said that if you learn mathematics, physics and chemistry well, you will not be afraid to go all over the world.

This is not a fabrication out of thin air, mathematics, physics, and chemistry are the cornerstones of the first industrial revolution in modern times.

Liu Hong gradually began to speak loudly in front of the stage, and the teachings in the front row, including Chongzhen, frowned.

The heart said that our Ming Dynasty only has Confucianism and science, what is the principle of all things, the principle of physics, the old man has never heard of it for most of his life.

The mountain chief must feel that there is no sense of existence in the engineering college, but if you want to find a sense of existence, you often come to the engineering college, but you are the mountain chief, why don't you come once a month.

Even if you want to find a sense of existence, it is not enough to call some disciples to come, so why bother to call them these old decays together.

"Mountain Chief, Cheng Zhu Science is the study of saints, I rely on this learning to educate all people, although you are the head of the mountain, you must not slander the study of saints!" One of the teachers in the second row was more stubborn, and directly got up and retorted.

"Dare to ask this gentleman's name?" Liu Hong knew early on that for these elderly teachings, his remarks were a bit rebellious, so he was not annoyed to see someone bluntly refute them.

"Under the civil science teaching, Li Cunhou." Although this person knew that refuting the mountain chief was likely to be fired, he still stubbornly said.

Cheng Zhu's science is deeply rooted in the hearts of the people, and it can even be said that it has penetrated into the bone marrow of all people, and few dare to question it, and he himself has been studying hard several times before he has to change his career to make a living in engineering.

"So can Mr. Li use Cheng Zhu's learning to answer a few doubts for the chief of this mountain?" Liu Hong gradually said again.

"I am only shallow in the next generation, but I ask the mountain chief to ask questions, but everything you know, you know everything." Li Cunhou twisted his head and said.

"Dare to ask Mr. why the sun rises in the east and sets in the west?" Liu Hong said casually.

"The golden crow is attached to the sky by the sun, and the sun, moon and stars are like this, which is the saying of the heavens." Li Cunhou thought about it for a long time and couldn't find the answer from Cheng Zhu Lixue, so he had to move out the Hun Tian theory of his ancestors.

The ancients believed that the earth was the center of the universe, the sky was immovable, and the sun, moon and stars revolved around the earth, but they had never explored right and wrong and their reasons.

"Then the chief of the mountain asked him again, when the fruit on the fruit tree is ripe, how does it fall instead of going up?

Why do fireflies glow? Why do sunflowers always face the sun?

Why do all things bloom in spring and autumn, and why do leaves change color?

Why is it possible to exhale white gas in winter but not in summer?

Why do you see lightning first, and then you hear thunder?

……”

Liu Hong gradually knew that as long as he was asked to explain, he would definitely be able to stump this Li Cunhou, but he did not get to the bottom of it, but threw out a series of new questions.

"This ......" Li Cunhou was directly confused by a large number of questions.

He racked his brains to find the answer from the Confucian classics he had studied, but his face was red and he was stunned that he didn't know the answer to any of these questions.

"I don't know the essence of Confucianism, but I can't ......explain the learning of a saint," Li Cunxiao saw that all eyes were focused on him, and he only felt that his face was hot.

"Mr. Li, please sit down!" Liu Hong gradually waved his hand to sit down in the back of the village, and then lifted the red cloth on a tray on the table.

The two trays on the table were the props of Liu Hongji's teaching, and in the open tray were a boiled potato, two wires of different colors, and a small cup made of glass.

Inside the glass, several ants crawl around the bottom of the glass, trying to find a way out and escape.

"Look, you guys, here's a boiled potato, a copper wire, a zinc wire, and a couple of live ants." Liu Hong gradually walked around the teachings with the plate, and then put the plate on the table in front of Chongzhen.

Everyone didn't know what elixir Liu Hongjian was selling in the gourd, and they all looked at the tray.

Liu Hongqian then inserted the copper wire into one end of the potato, and then the zinc wire into the other end, and wrapped a piece of cotton cloth around the copper wire and the zinc wire for insulation.

"The moment has come to witness the miracle, and behold!" Liu Hongjian pinched the copper wire with his left hand and the zinc wire with his right hand, touching the ends of the two wires together.

Zizi - a small spark flashed at the end, and the spark was so small that you couldn't see it without widening your eyes.

Uncle Chongzhen, who was the closest, trembled, he had never seen such a magical thing, and Uncle Song and Uncle Xu beside him also widened their eyes.

Liu Hong gradually fell silent, and poked two wires at the ants in the glass.

As soon as the two wires touched, a poor ant was damned, and after a little struggle, he lay down in the glass and did not move, and then there was a hint of burnt paste in the air.

Ants ...... potatoes Poisoned?

Chongzhen glanced at Uncle Song and Uncle Xu left and right, his eyes were full of horror, what is the truth in this? Why is there such a strange thing?

They couldn't think of why the potato might be poisoned.

Liu Hong gradually poked at the other ants one after another, and lay down three times before it had no effect.

Then Liu Hong gradually pulled out the wire on the potato, peeled the skin and ate half of the potato in one bite.

Uncle Chongzhen's face immediately changed, and he said in his heart that even if you want to teach, you can't fight so hard, if you are also poisoned, what can you do, I believe that you can't do it?

"What you just saw is not a miracle, it's called science! Also called electricity! It is a simple physical phenomenon. Liu Hong gradually brought the tray to the table in front of the podium and said.

Potato power generation is the first small experiment that primary school students learn in physics, and its principle is simply known to everyone.

The main thing is that two pieces of metal are needed, one as the anode, which is the electrode with low potential, such as zinc, and the other as the cathode, which is the electrode with a positive charge, such as the metal copper.

The acidic substances inside the potato react chemically with zinc and copper, and when electrons flow from one end to the other, the electrical energy is released.

Zinc is chemically more reactive than copper, and when both metals are in acid at the same time, zinc loses electrons, which travel along the wire to the copper sheet, forming an electric current.

"In time, if my Ming engineering disciples understand the reason, we can use this electricity to benefit all people, electricity can be used for lighting instead of candles and kerosene, and electricity can also be used to drive equipment without manpower......"

Liu Hong gradually simply lifted a few chestnuts, but it seemed that Uncle Chongzhen was confused.

They had never seen what electric lights looked like, let alone the devices that powered them by something called electricity, and they couldn't even imagine what it was like.

"Hmm...... If this current is increased by a hundredfold, no matter how human or animal touch it, they will die! Liu Hong gradually felt that the chestnuts he had just raised were not straightforward enough, so he changed his words.

As soon as he said this, Chongzhen's old eyes immediately brightened.

If this kid didn't deceive him, as long as he could increase this electricity to the point that people and animals would die at the touch of it, then against foreign enemies, would he still need to take the lives of Ming soldiers to fill it?