"Bang Bang~" Chen Xu slapped the podium a few times, and after everyone in the classroom was quiet and turned their eyes, he gritted his teeth and said, "Do you really want to see the real barometric test?" ”

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

"Well, two days later is the Mid-Autumn Festival, Ben Hou conducted an unprecedented air pressure experiment in Keju Square, everyone has the experience of using clay pots to draw water, when the clay pot is put into the water, there will be bubbles coming out of the mouth of the can, these bubbles are the air in the tank, in fact, you can see it, but you don't pay attention to it on weekdays, the gas in the tank can only be filled with water after discharge, this is also common sense in life, right?"

"Hou Ye's words are relatively clear and clear, and this is true!" Many nodded their heads in agreement.

"So that means that there is air in the jar first, and when it is filled with water, the air inside is squeezed out, and if we have a way to fill an airtight container with water, and then empty the water, then there should be neither water nor air in the container, right?"

"Yes!"

"What happens to an airtight container with neither water nor air?" Chen Xu asked loudly.

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

This phenomenon is not noticed on weekdays, it stands to reason that nothing should happen in a sealed container without water, but there will indeed be bubbles when the clay pot is filled with water, that is to say, there should be some invisible gas in the clay pot, the reason why many people are unwilling to believe and admit is that there is only one reason, that is, this so-called gas cannot be seen and touched, so it means that there is nothing, so it is called air.

But Hou Ye said that air is not really empty, but a very complex gas mixture, and there is a strong pressure like water, so the question is, how to observe this pressure.

"You don't know, right, that Ben Hou told you, if it is an ordinary glass container, it will be instantly squeezed by the atmospheric pressure outside the container, if it is a container made of iron sheets, it will also be deformed because of the pressure, only the container is strong enough, it can resist the strong air pressure, but this pressure can not be resisted even by several strongest horses......"

"Master Hou, I don't know if the horse can resist, you can just say it, how to do this experiment, we will help prepare the experimental materials." One of the instructors shouted to his feet.

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

"Well, you can arrange for someone to go to the experimental factory outside the city, and ask the machine factory to help make two hollow hemispheres with a diameter of three feet and a pull ring, one of which has a small hole left for filling water, and the other hemisphere has a water outlet and a closed faucet. Note that the two hemispheres must be the same size, the edges should be polished flat and smooth to be able to be stitched together, and by the way, the craftsman must make a sturdy water pump, and the water poured into the two hemispheres must be pumped out at that time, and the figure will look like this......"

Chen Xu drew as he spoke, and soon drew two simple hemispherical devices, and then without saying much, he dropped the chalk and left the laboratory.

In the junior high school physics of later generations, there were two classical physics experiments, one was the gravitational acceleration test in which two iron balls landed at the same time, and the other was the Magdeburg hemispheric atmospheric pressure test.

Both of these tests are not too complicated, although the Magdeburg hemispheric test is relatively difficult, but according to Daqin's current industrial manufacturing strength, it is easy to make equipment that meets the experimental conditions.

Not long after Chen Xu left the College of Engineering, the news that Qinghehou was going to conduct another large-scale experiment on the Keju Commercial Plaza during the Mid-Autumn Festival also spread with the mouths of the students and craftsmen who participated in the lecture, and soon became a topic of conversation among the people of Xianyang.

In fact, three years ago, the experiment of two copper balls landing at the same time still has not come out yet, and the enthusiasm of the Academy of Sciences and the people has slowly subsided, and Chen Xu has never said the real reason why the two copper balls landed at the same time.

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

But not to mention that there are also benefits, at least under the continuous pursuit of Zhang Cang and some other scholars who are interested in mathematical physics, they have begun to understand that there is a stable force between heaven and earth that cannot be resisted, although it is not clear the reason and theory for the existence of this force, but at least it has begun to move in the right direction.

The hemispheric test process that Chen Xu wants to carry out, which was once called Magdeburg, will later be recorded in the history books of mankind as the Xianyang Keju Square test, which will prove the existence of atmospheric pressure to human civilization, so as to slowly unveil the mystery of the air that human beings breathe every day.

Two days passed in a flash.

Chen Xu arranged for someone to send the collected petals to the chemistry laboratory every day, and then transported the distilled essential oil and alcoholic distilled water back to the Qinghe Courtyard, where a group of wives and maids such as Ying Shiyan and Meng Wanshui Qingrou prepared their favorite perfumes to match the designed perfume packaging.

In order to ensure that the two hemisphere tests 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 hemisphere, but obviously his worries are superfluous, the two hemispheres were successfully cast to the completion of the polishing, it only took one day to complete, in order to meet Chen Xu's requirements that must be completely sealed after closing, the craftsman also used a lathe to drill threaded holes in the casting hemisphere, used raw silk as a raw material belt, and installed the latest faucet developed at present, and for the sake of beauty, The time and place of the experiment were also inscribed on the two hemispheres.

In the midst of the busyness, the Mid-Autumn Festival came as scheduled, and after breakfast, Chen Xu came to the jubilant Keju Square with a large family of people such as Shui Qingrou and Ying Shiyan Mengwan.

Hundreds of acres of Keju Square has long been overcrowded, the Qin people and Hu people are bustling, but most of the people are blocked outside by the forbidden army, the closest to the center of the square, the five major colleges and experimental factories and the newspaper hall are thousands of people gathered together, everyone has a nameplate representing their own department on their chests, one by one looks excited and excited, and in the crowd, there are many rich people and princes in gorgeous clothes.

Zhang Cang, vice president of the Academy of Sciences, Zhao Qing, the supervisor, Sun Shuyi, the secretary, several highly respected professors of the College of Engineering and a group of Mo tutors who are proficient in institutional skills, the vice president of the College of Agriculture, and Tang Ting, the hemp pole of the experimental factory, were all present, and even the two untouched departments of the Health Center and the College of Liberal Arts had a lot of people coming, and a group of editors-in-chief such as Chen Ping, the general affairs secretary of the newspaper, and Fu Anqiucheng, were also listed, and even a group of gentlemen such as Meng Yun were also crowded in the front, all of them were watching the two beautifully made and strange iron hemispheres placed on the ground at this time.

"Hurry up, Master Hou is here!"

With the shouting, the crowd dispersed on both sides, Chen Xu was wearing a brocade robe and a jade crown, and he walked with a group of wives under the escort of the guards.

"Master Hou, you finally remember to come to do the experiment!" Qi Laosan jumped in front of Chen Xu and shouted loudly.

"Sister-in-law, don't waste time, this is going to be done with two iron scoops!" Meng Yun also tugged on Chen Xu's sleeve excitedly.

"Don't worry, let me check the test equipment first!" Chen Xu was staggered and dragged in front of the two hemispheres by a group of stumbling gentlemen, and without tidying up his clothes and hair, he squatted down and carefully moved them away and looked at the two semicircular spheres.

Cast in fine iron, the ball wall is half an inch thick, there are pull rings on both sides for installing ropes, the water inlet and drain faucet are also very finely installed, and the pumping cylinder has been prepared.

Chen Xu asked the two craftsmen to put the two hemispheres together and observe it carefully, and felt that there was almost no problem, so he looked around and said with a smile: "This experiment is very simple, everyone should already know what Ben Hou wants to prove, so at the moment Ben Hou is not enough to say, please get out of the way, go and lead a few horses, the bridles and reins are all loaded, and the experiment will start immediately!" ”

"Let it go, back off...... Go back ...... again"

Under the reprimand of a group of teachers and craftsmen from the Academy of Sciences and the College of Engineering, the five academies and some onlookers with status and status also cooperated and began to retreat, but the ordinary people watching outside did not know, and saw that there was movement inside, so they all began to squeeze inside desperately, trying to see how the so-called atmospheric pressure experiment was.

"Don't squeeze, squeeze and flog again~~" As a leader of the forbidden army roared, many soldiers showed their leather whips on their waists, and the noisy and crowded situation subsided slightly.

And Chen Xu didn't pay attention to the noise of the civilians, most of these ordinary people came to see the excitement, and the people who are really knowledgeable and literate are almost all concentrated in the five colleges at the moment, so the people of this experiment can only watch a sound, and they don't expect them to think out any profound truths, so Chen Xu didn't want to put this simple experiment in the Keju field, which would not only be troublesome, but also destroy the turf of the Keju field, and the gains outweighed the losses.

"Master Hou, it's all ready!" After more than ten minutes of hustle and bustle, a teaching report was made at the School of Engineering, which was in charge of the experiment.

"Okay, close the hemisphere and start filling the water!" With a wave of Chen Xu's big hand, a group of craftsmen swarmed up, and soon put a sealing gasket made of sheepskin between the two hemispheres, carefully put the two hemispheres together, and then tied the two hemispheres together with hemp rope and began to inject water into them through the water inlet hole.

The process of closing the two hemispheres and filling water Chen Xu has told the factory that he has already done experiments, so this step is very familiar to a group of craftsmen, and it was completed quickly, and the volume of this huge iron ball with a diameter of three feet has been roughly estimated by Chen Xu to reach about 0.13 cubic meters, so it is enough to fill it with more than 100 kilograms of water.

After filling it with water, Chen Xu instructed the craftsmen to bolt the water injection hole around the raw silk and screw it in to completely block it, and then carefully observed that the iron ball filled with water was indeed not leaking, and then turned around and looked at the surrounding crowd again: "Everyone, you can see clearly now, this iron ball has been filled with water, if the water in it is emptied now, there will definitely be nothing in it, including the air that everyone says on weekdays, right!" ”

"Yes~~" There was a lively commotion all around.

In fact, the content of Chen Xu's lecture at the College of Engineering two days ago and the siphon test have now been spread among the five major colleges and the folk group of monks, because the siphon test is extremely simple, and many people who are watching the excitement at the moment have even done the process of the siphon test themselves, so they are more interested in Chen Xu's large-scale experiment, and they all want to see how the immortal disciple Qinghehou proves that the empty air is also stressful.

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

Many people have also understood the meaning of this process, that is, Chen Xu wants to keep the iron ball free of water and air and keep it truly empty.

Because of the existence of atmospheric pressure, the water in the iron ball could not flow out without much put, Chen Xu asked the craftsmen to use a water pump to connect to the water outlet to pump water, and after each full pump, close the faucet to ensure that there is no outside air to enter, and so on dozens of times, until several craftsmen blushed and their necks were thick and could not pull out the lever of the water pump, Chen Xu ordered to completely close the faucet and let everyone stop.

At this time, the water in the iron ball has almost been emptied, as long as the iron ball does not leak, the air pressure outside is enough to press the two hemispheres together.

"Untie the twine!" Chen Xu waved his hand calmly, and soon the hemp rope tied to the outside of the iron ball was untied, Chen Xu kicked on the iron ball, only to see that the iron ball, which was originally two halves, was like the whole at this time, and rolled out more than a foot away, but there was no sign of separation.

"Hey, that's weird, what's the principle?" All the onlookers were pulling their beards in a daze almost at the same time.

"Master Hou, this is not scientific, it is obviously two halves, according to the Tao to understand the rope, they will be separated!" Chen Ping squatted in front of the iron ball with an incredulous face and muttered 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 of the fit did not move at all, as if it was a whole iron ball.

"It's not scientific, it's so unscientific!" A group of gentlemen also shouted and kicked the iron ball around with a popular mantra nowadays.

"Who said that it is unscientific, it is scientific if it can't be kicked open, and it is not scientific if it is kicked open, if it is the same as what you think on weekdays, why would Ben Hou make such a big battle to do this experiment!" Chen Xu smiled and waved his hand, and instructed the craftsman to bring two horses and tie the traction rope with a thickness of more than an inch to the handle of the iron ball.

"You are optimistic, the following test is the strongest support to prove the existence of atmospheric pressure, you think that the air is empty, but in fact, it is not, in addition to the water vapor that Ben Hou also said before, the air is an extremely complex mixture of gases, and now the air and water in this iron ball are emptied but the reason why they can be combined is because they are suppressed by the air outside, just like people feel pressure when diving, the deeper the dive, the heavier the body is the same reason, although this pressure can not be seen and touched, But I can feel it, and now I will use these two healthy horses to pull these two hemispheres, and let you see how much force the atmospheric pressure is, and start~"

After Chen Xu finished speaking, the two horsemen began to scold and whip the two strong horses, and the two horses also pulled hard to both sides, and the more than an inch thick hemp rope made a creaking sound, but no matter how the horsemen whipped and how the two horses worked, the iron ball hanging in the middle did not show the slightest sign of separation.

"Bring two more horses to ......"

Chen Xu waved his hand, and the groom once again brought two equally strong horses, and after putting on the reins and leashes, the four horses pulled together on both sides, but the big iron ball still did not move.

"Two more horses!"

A few minutes later, Chen Xu spoke again, and with the six horses working together, the jaws of the people watching the scene were all stunned.

But soon, the number of horses increased to ten.

"Click~"

Under the crazy pull of ten strong horses, the iron ball finally couldn't bear the huge pull, with a cracking sound, the huge iron ball split into two halves and was pulled and flew out, and the ten healthy horses all suddenly lost control and neighed and rushed out, and the leading horses were even more hooves and rolled to the ground, and the chaotic situation frightened the surrounding crowd and fled, and it took a while to calm down.

"Everyone, it is said that hearing is false and seeing is believing, whether you understand this experiment or not, whether you think it clearly or not, but I need everyone to understand that atmospheric pressure is real, and it is very powerful, just to pull away such a small two halves of iron balls requires ten healthy horses to succeed, and the airtight container that is exhausted of air Ben Hou calls it a vacuum, and it is also a real nothing, and in a vacuum environment, no life can survive, so what is placed in a vacuum container will not rot and deteriorate, so, From now on, you will never say that the air is empty......"

The shepherd said

Recommend my friend Bianmo's interstellar sci-fi "Predatory Starry Sky", friends who like sci-fi and steam genres can go and take a look, and friends passing by also please collect and support it by the way, thank you!

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