Zhang Nan thought about it, so he decided to use a scientific experiment that modern middle school students know to explain this problem to Sun Simiao. That's right, what Zhang Nan thought was the experiment of the guinea mouse, which was to put the mouse in a closed container, and then put a lit candle in the container, and when the candle went out, the mouse died.

This indirectly proves that it is oxygen that breathes.

Zhang Nan thought of this, so he said to Sun Simiao: "Since Sun Zhenren wants to know, then I will tell Sun Zhenren what oxygen is." After Zhang Nan finished speaking, he looked at the surrounding environment and found that everyone was still in Du Mansion, so he said.

"Your Majesty, Sun Zhenren, Lord Du has just rested, why don't we go to another place and do experiments." After Zhang Nan finished speaking, Li Er nodded noncommittally, after all, he was doing experiments in the patient's house in such a grand manner, although Li Er was the emperor, others would not say anything, but if Li Er did this, he would feel that his face could not be hung up.

"Well, let's go to the military academy then, I can just go and visit Cheng Qian." Li Erdao, although Li Chengqian is now locked up, and it was ordered by Li Er himself, but after all, he is his own son, and Li Er is also a little distressed when he has locked Li Chengqian in a small black room for so long.

After a short time, the three of them came to the military academy, and the experimental site was placed in Sun Simiao's small courtyard, and after all the experimental equipment was ready, Zhang Nan found that Li Er also asked Liu Bing to move a chair for himself and sit in the courtyard.

"Huh? Your Majesty, aren't you going to see the crown prince? Zhang Nan looked at Li Er, who was still and asked.

"Don't be in a hurry, Cheng Qian can go to see it at any time, I want to see what this oxygen is first." Li Er waved his hand impatiently, signaling Zhang Nan to stop grinding and start the test quickly.

Zhang Nan had no choice but to pick up a sealed porcelain jar and said: "Nachen will start now, and the next thing is the moment to witness the miracle." Although Zhang Nan's line was an old-fashioned sentence, it still stunned Li Er and Sun Simiao.

Since he couldn't find a transparent container, Zhang Nan reluctantly replaced it with a clay pot, although Zhang Nan could completely change two glass containers from the system, but Zhang Nan didn't want to waste this point, after all, this thing can't be used once, anyway, if you can't see it, it won't affect the results of the experiment, so Zhang Nan decided to be a grande and talk about it.

It's hard to find mice in the military school, because the houses in the military school are cleaned every day, and even if they don't live in people, they have to be cleaned every day, so there are fewer mice in the military school, but there are fewer mice and more voles.

The military academy has its own vegetable patch, so Cheng Huaimo, who was ordered to catch mice, didn't take much time to catch a string of voles for Zhang Nan.

After tying up the vole's legs and putting them into the clay pot where the candles had been lit, Zhang Nan clapped his hands and said, "Okay, it's done." ”

Li Eryi heard that Zhang Nan's experiment was finished, and asked strangely, "It's over?" ”

"It's over."

"It's ....... What about oxygen? Li Erdao.

"It's not like a vole breathing in it, and after a while the vole will die." Zhang Nan said.

"And what does the death of the vole mean?" Sun Simiao asked.

"If you die, it means that the oxygen is exhausted, which proves that everything lives on oxygen, and everyone inhales oxygen and exhales carbon dioxide." Zhang Nan said as a matter of course.

"It's just such a clay pot, won't the vole suffocate to death after staying in it for long?" Sun Simiao frowned and said, obviously Sun Simiao did not understand the purpose of Zhang Nan's experiment.

"Yes, yes, it's similar to suffocation, except that suffocation is to make the vole not breathe oxygen, and I'm just using up the oxygen." Zhang Nan said with a smile.

"Is there any difference between the two?" Li Er asked.

"This ...... Judging from the results, it is no different. Zhang Nan scratched his head, after all, using up the oxygen is suffocating the vole, and there is really no difference between the two.

"Then what's the point of you showing me this?" Li Er said with a look of contempt that what Zhang Nan did was to prevent the vole from breathing, but he didn't prove what this oxygen was at all.

"Damn, I actually let Li Er despise me." Zhang Nan said in his heart, after all, Zhang Nan came back with the common sense accumulated in later generations for more than a thousand years, and now he actually made Li Er despise, how could this make Zhang Nan speechless.

"But what kind of oxygen is, you still haven't made it clear, little friend." Sun Simiao looked like he was digging into the roots, and Zhang Nan was very big-headed.

"You're going to dig into your ancestral grave." Zhang Nan secretly complained in his heart.

"Oxygen is the breath we breathe into our body, the breath we exhale is carbon dioxide and other gases, if we are in a house without oxygen, we will die like that vole, it's that simple, understand?" Zhang Nan said.

"But how do you prove that we're taking in oxygen and we're spitting out that dioxide? If we inhale dioxygen or something, how can this be explained? ”

“......”

Zhang Nan wasted all his strength, but still didn't explain to Sun Simiao and Li Er what the gas contained in this air composition was, and finally Zhang Nan gave up, and Li Er also left to find Li Chengqian with infinite contempt for Zhang Nan with an expression of listening to nonsense.

And Sun Simiao stayed in the courtyard because Sun Simiao wanted to see what the electronic blood pressure monitor that Zhang Nan had been putting next to him was.

After this incident, Zhang Nan understood that it is impossible to step from ancient science to modern science, just like people can't take too big a step when they walk, because if they take too big a step, it is easy to pull eggs.

Now Zhang Nan feels like he has pulled an egg.

"Rome wasn't built in a day." Zhang Nan lamented.

"Little friend, what kind of horse is this mule horse? Is it a horse born of a mule and a horse? Sun Simiao heard a new term from Zhang Nan's mouth again, and couldn't wait to ask.

"The mule is not fertile because it is a combination of a horse and a donkey and has reproductive isolation." Zhang Nan still knows this common sense.

"What is reproductive isolation?"

“...... Oh my God, kill me, I'm not going to sell knowledge anymore. ”

"Eh, Xiaoyou, you have to make it clear, it's not good to say half of it, isn't it clear when you say the old way? Haven't you always been unclear if you don't talk about the old way? So you still have to make it clear to Lao Dao, you don't make it clear that Lao Dao can't sleep well this night, Lao Dao has been taught by you today, as if he has seen through what the Tao has been pursuing, Xiaoyou, you have to make it clear. ”

Seeing that Sun Simiao had been chattering in front of his eyes, Zhang Nan seemed to see the Tang Seng in "Journey to the West" who couldn't stop for a moment.