"When paper is placed in water, it will naturally float up and float on the water." Li Xiaogong looked at Xia Hongsheng and said, "But since the virtuous nephew asked so, is it possible that this paper can still sink to the bottom?" ”

Xia Hongsheng smiled and didn't speak, just picked up a piece of paper, rubbed it vigorously, and kneaded the piece of paper into a small paper ball, and then threw it into the copper basin, and the paper ball immediately sank to the bottom.

"Uh, the virtuous nephew is ......" Li Xiaogong was originally full of novelty, but the gap at the moment is a little big: "It's also a good nephew who wants to use a lot of methods, but it's a mess!" ”

Xia Hongsheng didn't speak, but smiled and picked up another piece of paper, and then spread it out and put it in the basin. Without any suspense, the paper naturally floated on the water.

Li Xiaogong looked at Xia Hongsheng's actions, thought about it, and didn't understand, so he asked, "What does this mean by the virtuous nephew?" ”

"These two pieces of paper are the same, but why is one sunk to the bottom and the other is floating on the water?" Xia Hongsheng smiled and asked rhetorically.

"Naturally, it's because the virtuous nephew twisted that piece of paper?" Li Xiaogong said.

"yes, the same thing, just because I twisted one of the pieces of paper into a ball, and it sank to the bottom." Xia Hongsheng said: "Then it can be said the other way around, the same piece of paper, I unfolded it, became bigger, and it changed from sinking to floating on the water." ”

Li Xiaogong was stunned: "The meaning of the virtuous nephew is ......"

Xia Hongsheng smiled again, turned his head to look at Li Tai and asked, "Xiaotai, let me ask you, which is heavier, a thousand catties of iron or a thousand catties of paper?" ”

"Naturally, iron is heavier!" Li Chongyi didn't think about it, and replied when he opened his mouth.

Li Tai rolled his eyes, and turned his head to look at Li Chongyi helplessly: "It's all a thousand catties, which one is heavier?" Just as heavy! ”

Li Chongyi was stunned. Then he understood, laughed, and was glared at viciously by Li Xiaogong.

"Then you say, will a thousand catties of paper float if it is thrown into the river?" Xia Hongsheng asked again: "What about a thousand catties of iron?" ”

Now everyone was silent.

Li Tai felt that Xia Hongsheng asked this, there must be a trap in it, so he had to think about it. Li Chongyi is because he lost his ugliness just now. Now I don't want to say it first, while his father wants to gouge out his eyes again.

After thinking for a while, Li Tai said: "Paper can float, but iron can't." ”

"Why not? Obviously, they are all 1,000 catties, the same weight. Xia Hongsheng spread his hands and asked with a smile.

Everyone was asked, the density is not the same, they naturally can't say it, Xia Hongsheng is actually sophistry, misleading them in the direction they want them to come to the conclusion.

"Virtuous nephew. This paper is not the same thing as iron, so even if the iron as big as the tip of the finger is still in the river, it can't float, let alone a thousand catties? Li Xiaogong was puzzled and asked: "If the 1,000 catties of paper are trapped together and thrown into the river, they will still sink to the bottom, unless they are like Fang Caixian's nephew, a piece of paper is spread out!" ”

"That's right!" Xia Hongsheng clapped his hands and said with a smile: "Sure enough, he deserves to be an uncle." Immediately figured it out. ”

After speaking, Xia Hongsheng pointed to the copper basin again. said: "Look, what happened to the paper that just sank to the bottom? ”

The paper, which was originally crumpled into a ball by Xia Hongsheng, was full of water at the moment, and then dispersed, so it slowly floated back to the water.

"Float up! Father, look, it's floating up! Li Chongyi pointed to the copper basin and shouted.

"! The old man knows! Li Xiaogong was very annoyed by his son, who was not calm. felt that he was shocked on the surface and did not have the demeanor of a famous general of the Tang Dynasty at all, so he was very annoyed.

Xia Hongsheng pointed to the two balls of paper in the copper basin and said, "Uncle, look at these two pieces of paper. It had just twisted into a ball and sunk to the bottom, and now it was slowly spreading out. It gets bigger, and it floats again. And this paper is flattened at the beginning, so it doesn't sink to the bottom. So can we spread this iron the size of a paper ball into a piece of paper, two sheets of paper, or even a hundred sheets of paper, so can it also float? What does my uncle think, is it worth a try? ”

"This ......" Li Xiaogong looked at the sheets of paper in the copper basin in shock.

Li Chongyi was also confused, it seemed that Xia Hongsheng's sophistry was very successful, and both of them were stunned by Xia Hongsheng.

An object immersed in a liquid is subjected to an upward buoyant force equal to the gravitational force of the liquid dislodged by the object. This is the famous Archimedes' law, which is also known as the law of buoyancy. Ordinary steel is solid, so when it sinks into the water, the buoyancy is the weight of the same volume of water. The weight of iron is naturally much heavier than that of water in the same volume than in the same volume of iron, according to Archimedes' law, so the buoyancy is much smaller than the gravity of iron, so the iron sinks. And iron ships are different. First of all, the ship has a cabin, and the cabin is air, and the design of the hull and bottom shape of the ship makes it sink to a certain extent, and the volume of the water discharged will be much larger than the volume of iron submerged in the water. When the weight of the discharged water is equal to the weight of the iron ship, the ship will not sink again.

The same is true of the paper ball just now, Xia Hongsheng twisted it into a ball, its volume became smaller, the weight was concentrated, and the amount of water discharged was less, less than its weight, and it sank to the bottom. The flat paper, which has many places to contact the water surface and has a large amount of drainage, will not sink to the bottom.

Xia Hongsheng can't talk to them about Archimedes' law now, so he can only guide them in this way.

"What the virtuous nephew said is novel and tight." Li Xiaogong pondered for a moment and said, "If you can really build a ship with steel, then after taking over the sampan, wouldn't you be afraid of the fire attack of the enemy's sailors, nor will you be afraid of the other party colliding with the ship?" ”

is worthy of being a famous general of the Tang Dynasty, and he is still in the clouds and has not stared at what's going on, but he first thinks of the benefits of steel ships in the war.

Xia Hongsheng immediately replied: "Uncle is worthy of being a famous general of our Datang!" The ability to draw inferences from one another, the little nephew can't beat the horse! Listening to his uncle's words, the little nephew realized that if he could build a steel warship, then who else could beat our Tang Dynasty on the water?! They drive wooden boats, let's drive iron boats, if they hit us, I'm afraid that he will fall apart. Don't be afraid to set fire, where can steel burn? Don't be afraid to shoot arrows, arrows can't hit the hull of a ship at all, let alone shoot rockets! ”

"Not bad! Not bad! Yes, extremely! Li Xiaogong was taken aback, immediately laughed, and said: "In this way, if you can really make a steel warship, it will be a big deal!" Good! The old man attacked Liang in the south of the Yangtze River back then, trained sailors, and built warships, so he really has a good shipbuilder in his hands! The virtuous nephew can rest assured, at this time, it will be wrapped up in the old man, and he will definitely find the best craftsman to assist the virtuous nephew in trying to make a boat out of steel! (To be continued.) )