"Baba~" Chen Xu slapped the podium a few times. After everyone in the classroom calmed down and his eyes turned, he gritted his teeth and said, "Do you really want to see the real air pressure test?"

"I want to see~" countless answers rang out in the classroom.

"Okay, two days later it is the Mid-Autumn Festival. I am in Cuju Square to conduct an unprecedented air pressure experiment. Everyone has the experience of using a clay pot to fetch water. When the clay pot is put into the water, bubbles will emerge from the mouth of the can. These bubbles are the air in the water tank, which is actually visible. You just don't pay attention to it on weekdays. Only after the gas in the water tank is discharged can you fill it with water. This is also common sense in life, right?"

"The Marquis said this clearly and clearly, it is true!" Many people nodded in agreement.

"So that means there is air in the jar first, and when it is filled with water, the air inside is squeezed away. If we have a way to fill a closed container with water and then evacuate the water inside, there should be neither water nor air in the container, right?"

"right!"

"What will happen to that airtight container without water or air?" Chen Xu asked loudly.

Everyone looked at each other, feeling a little confused in their minds.

No one pays attention to this phenomenon on weekdays. Logically speaking, a sealed container without water should not happen, but bubbles do appear when the potted pot is filled with water. In other words, there should be some invisible gas in the pot. The reason why many people are unwilling to believe and admit it is still only one reason, that is, this so-called invisible gas is invisible and intangible, so it means nothing, so it is called air.

But the Marquis said that air is not real empty, but a very complex mixed gas, and it also has strong pressure like water. So the question is, how should this pressure be observed?

"Everyone doesn't know, right? Then Benhou tells you that if it is an ordinary glass container, it will be instantly squeezed out by the atmospheric pressure outside the container. If it is a container made of iron, it will also be deformed due to pressure. Only when the container is strong enough can it resist the strong air pressure, but this pressure cannot resist even the strongest horses..."

"Marty, I don't know if the horse can resist. Just tell me how to do this experiment. Let's help prepare the experimental materials." A teacher stood up loudly.

If you don’t believe it or not, everyone wants to see how Chen Xu proves the existence of air pressure.

"That's good. You arrange for someone to go to the experimental factory outside the city and ask the machinery factory to help make two hollow hemispheres with three feet in diameter and pull rings. One of the hemispheres has a small hole for water injection, and the other hemisphere has a water outlet port and a closed faucet is installed. Note that the two hemispheres must be the same size, and the edges must be polished and smooth, so that they can be tightly sewn together. By the way, the craftsmen must also make a solid pumping tube, and then the water poured into the two hemispheres must be pulled out. The figure is roughly like this..."

Chen Xu talked and drew, and quickly drew two simple hemisphere devices. Then, he didn't say much, left the chalk and left the laboratory.

There are two classic physics tests in later junior high school physics, one is the gravity acceleration test of two iron balls falling to the ground at the same time, and the other is the atmospheric pressure test of Madberg hemisphere.

Both tests are not too complicated. Although the Maddleborg hemisphere test is relatively difficult, according to Daqin's current industrial manufacturing strength, it is easy to make equipment that meets the experimental conditions.

Shortly after Chen Xu left the Institute of Technology, the news that Qinghehou was going to conduct another large-scale experiment on Cuju Commercial Plaza during the Mid-Autumn Festival was spread as students attending the lectures and craftsmen, and soon became a topic of relish for the people of Xianyang.

In fact, there is still no conclusion on the experiment of two copper balls landing at the same time three years ago. After a wave of enthusiasm among the Academy of Sciences and the public, Chen Xu has never explained the real reason why the two copper balls landed at the same time.

It’s not that he doesn’t want to, but that it’s useless to say it.

But it is also beneficial not to say it. At least with the continuous pursuit of some alchemists such as Zhang Cang who are interested in mathematics and physics, they have begun to understand that there is a stable force between heaven and earth that all things cannot resist. Although they are not clear about the reasons and theory of this force, they have at least begun to move in the right direction.

The process Chen Xu was going to conduct, once called the Madberg hemisphere test, will be recorded in human history books as the Xianyang Cuju Square test, from then on, and will prove the existence of atmospheric pressure to human civilization, thereby slowly uncovering the mystery of the air that humans breathe in daily life.

Two days passed in a flash.

Every day, Chen Xu arranged for people to send the collected petals to the chemistry laboratory, and then transported the distilled essential oil and alcohol distilled water back to Qinghe Villa, and taught Ying Shiman and Meng Wanshui Qingrou to make their favorite perfumes, so as to match the designed perfume packaging.

In order to ensure that the two hemispheres will not go wrong, Chen Xu arranged for people to go to the machinery factory several times a day to check the production progress of the hemispheres, but obviously his concerns were unnecessary. The casting of these two hemispheres was successfully completed until the polishing was completed. In order to meet Chen Xu's requirement that it must be completely closed after closing, the craftsman also used a lathe to drill threaded holes in the cast hemispheres, used raw silk as raw tape, and installed the latest faucets developed at present. In order to be beautiful, the experiment time and experimental location were engraved on the two hemispheres respectively.

In the busy life, the Mid-Autumn Festival came as scheduled. After breakfast, Chen Xu brought Shui Qingrou, Ying Shiman and Meng Wan and other family members to the crowded Cuju Square.

The hundreds of acres of Cuju Square were already crowded, with Qin and Hu people bustling, but most of them were blocked by the imperial guards. The closest to the center of the square, thousands of people from the five colleges, experimental factories and newspapers gathered together. Each of them had a nameplate representing their department on their chests, and they looked excited. Among the crowd, there were many rich men in gorgeous clothes and princes and princes.

Zhang Cang, deputy director of the Academy of Sciences, Zhao Qing, secretary Sun Shujiu, several respected professors from the School of Engineering and a group of Mohist tutors who are proficient in institutional skills, vice president of the Academy of Agricultural Sciences, and Magan Gongshusheng from the experimental factory, Tang Ting, were all present. Even the two unrelated departments of the Health Center and the School of Literature, many people came. Chen Ping, general affairs secretary of the newspaper office, Fu Anqiu Cheng and other editors were also listed, and even a group of dandy players such as Meng Yun were crowded in the front. At this time, they were all watching the two exquisitely made and strange iron hemispheres placed on the ground.

"Get back quickly, the marquis is here!"

With the shouts, the crowd was bustling and scattered on both sides. Chen Xu wore a brocade robe and a jade crown, and walked with his eight-character steps and led a group of wives to come with his guards.

"Mr. Marquis, you finally remember to do the experiment!" Qi Laosan jumped to Chen Xu and shouted loudly.

"Don't waste time with my sister-in-law. You need two iron ladles to do anything!" Meng Yun also pulled Chen Xu's sleeve excitedly.

"Don't worry, don't worry, let me check the test equipment first!" Chen Xu was staggered to the front of the two hemispheres by a group of playboys rushing up. He squatted down and moved it carefully and looked at the two semicircular spheres.

The fine iron is cast, the ball wall is half an inch thick, and there are pull rings for rope installation on both sides. The water inlet and drainage faucet are also installed and made very finely. The pumping tube for pumping has also been made.

Chen Xu asked the two craftsmen to put the two hemispheres together and carefully observed them. He felt that it was almost okay. Then he looked around and said with a smile: "This experiment is very simple. Everyone should have known what this marquis wants to prove. Therefore, I am not talking much at the moment. Please let go and lead a few horses to pick them up. The horse bridle and reins are all installed, and the experiment will begin soon!"

"Give it all, retreat... and back..."

Under the scolding of a group of teachers from the Academy of Sciences and the School of Engineering, the five colleges and some onlookers with status cooperated to retreat. However, the ordinary people watching outside were not sure. They saw that there was movement inside, so they all began to squeeze in, trying to see clearly what the so-called atmospheric pressure experiment was.

"Stop squeezing, squeeze and flogging again~~" As an imperial guard leader roared, many soldiers showed their whip around their waists, and the noise and crowding situation subsided slightly.

Chen Xu ignored the noise of the civilians. Most of these ordinary people are watching the fun. People who are truly knowledgeable and educated are now concentrated in the five major academies. Therefore, the people can only watch this experiment and do not expect them to think of any profound truths. Therefore, Chen Xu did not want to put this simple experiment in the Cuju field. This would not only cause trouble, but also damage the turf of the Cuju field, which would not be worth the cost.

"Mr. Marquis, you are all ready!" After more than ten minutes of bustling, a teacher report from the Institute of Technology, who was responsible for the experiment.

"Okay, close the half ball and start pouring water!" Chen Xu waved his hand, and a group of craftsmen rushed up, quickly putting a sheepskin sealing gasket between the two half balls, carefully putting the two half balls together, then tied the two half balls together with hemp rope and then began to pour water into it through the water inlet hole.

Chen Xu had already told the factory to conduct experiments on the process of filling the water with the two hemispheres, so a group of craftsmen were very familiar with this step and it was completed quickly. The volume of this huge iron ball with a diameter of three feet was roughly calculated by Chen Xu to reach about 0.13 cubic meters, so more than 100 kilograms of water were poured into full.

After filling the water, Chen Xu ordered the craftsman to wrap the water injection hole with bolts and twist it in and completely block it. Then he carefully observed that the iron ball filled with water did not leak water. Then he turned around and looked at the crowd around him again: "Everyone, I have seen it clearly now. The iron ball is filled with water. If the water inside is drained now, there will definitely be nothing inside, including what everyone says on weekdays, right!"

"Yes~~" There was a lively noise around.

In fact, the content of Chen Xu's lecture at the Institute of Technology two days ago and the siphon test have been circulating among the five major academies and the folk alchemists. Because the siphon test is extremely simple, many people who are watching the fun have even done the siphon test themselves. Therefore, they are more interested in Chen Xu's large-scale experiment and want to see how the immortal disciple Qinghehou proves that the empty air is also under pressure.

"That's good, turn on the faucet to drain the water!" Chen Xu nodded and instructed the craftsman to turn on the faucet. As the faucet was opened, the water that had just filled up was flowing out again.

Many people have already understood the meaning of this process, that is, Chen Xu wants to keep the iron ball neither water nor air in it, and to keep it truly empty.

Because of the atmospheric pressure, the water in the iron ball could not flow out without much water. Chen Xu asked the craftsman to use a water pump to connect it to the outlet to pump water. After each pumping one, he turned off the faucet to ensure that there was no external air in. After this repeated dozens of times, it was not until several craftsman blushed and used their strength to pull out the pull rod of the craftsman, Chen Xu ordered to completely turn off the faucet and let everyone stop.

At this time, the water inside the iron ball had almost been drained. As long as the iron ball did not leak, the air pressure outside was enough to press the two hemispheres tightly together.

"Unlock the hemp rope!" Chen Xu waved his hands calmly, and soon the hemp rope tied outside the iron ball was untied. Chen Xu kicked the iron ball, and saw that the iron ball, which was originally two halves, was rolling out more than one meter away like a whole, but there was no sign of separation at all.

"Hiss, it's strange, what's the principle?" Everyone onlookers were staring blankly at the same time.

"Marty, this is unscientific. It is obviously two halves. According to the understanding, they will separate the ropes!" Chen Ping squatted in front of the iron ball with an incredible face and murmured to himself.

"That's right, the two halves should be separated!" Meng Yun also kicked the iron ball a few times, and found that the two halves were not moving at all, just like a whole iron ball.

"It's unscientific, too unscientific!" A group of playboys also yelled at the popular mantra of the moment and kicked the iron ball around.

"Who says it's unscientific? It's scientific if you can't kick it away. If it's not scientific if you kick it away, it's not scientific. If it's the same as you usually think, why should I do such a big battle to do this experiment!" Chen Xu waved his hand with a smile, and instructed the craftsmen to bring two horses, tie the traction rope of an inch of thickness to the handle of the iron ball.

"Everyone is optimistic, the test below of this marquis is the most powerful support for proving the existence of atmospheric pressure. You think that the air is empty, but in fact, it is not the case. In addition to the water vapor mentioned earlier, air is an extremely complex mixed gas. The reason why the air and water in this iron ball are emptied but can be combined is because it is pressed by the air from the outside world. It is like a person who feels pressure when diving. The deeper the diving, the heavier the body is. Although this pressure is invisible and intangible, it can be felt. Now I will use these two strong horses to pull these two hemispheres, so that you can see how strong the atmospheric pressure is. Start~"

After Chen Xu said the order, the two grooms began to scold and beat the two strong horses. The two horses also pulled hard to both sides. The hemp rope was thicker than inch and made a creaking sound, but no matter how the grooms beat and how the two horses tried, the iron ball hanging in the middle showed no sign of separation.

"Take two more horses..."

Chen Xu waved his hand and a groom brought two equally strong horses again. After putting on the reins and traction rope, the four horses pulled them hard to both sides, but the big iron ball still did not move at all.

"Add two more horses!"

A few minutes later, Chen Xu spoke again, and as the six horses worked hard together, everyone who watched the scene was stunned and his chin was almost dislocated.

But soon, the number of horses increased to ten.

"Click~"

Under the crazy pulling of ten strong horses, the iron ball finally couldn't withstand the huge pulling force. With a cracking sound, the huge iron ball separated and was pulled and flew out. All the ten strong horses suddenly lost control and rushed out neighing. The leading horses even lost their hooves and rolled to the ground. The chaos scared the crowd around them and fled in all directions. It took a while for a while to calm down.
Chapter completed!