Looking at the dark crowd in the auditorium of the Academy, Li forget worry, the initiator, was unexpected.

He did not expect that when more than 2000 people crowded into the auditorium of the Academy, it would be like this... The degree of crowding was almost comparable to the railway station during the Spring Festival transportation of later generations.

The originally spacious walkway is now dark and full of people.

Xu Jingzong really took Li\'s orders seriously and carried them out.

Originally, Xu Jingzong was worried that these famous officials, scholars, eminent monks and eminent monks would be furious and lead to many incidents when they learned that the Academy arranged them to sit on the aisle floor.

But what Xu Jingzong didn\'t expect was that none of the more than 1000 people objected. They all obeyed the arrangement of the academy and sat on the floor without complaint.

In fact, Xu Jingzong is completely worried.

These people are more worried that they have annoyed Li forget worry and are unable to listen to the knowledge handed down by his ancestors. Therefore, for them, even sitting on the floor listening to the lecture is enjoyable.

The students of the Academy were surprised to see so many strangers appear.

Fortunately, the students of the academy have seen the world.

In particular, those students in the second grade get along with Prince Li Chengqian and others day and night, and all have developed a big heart.

A few days ago, this group of students of the Academy saw the emperor weiguangzheng with their own eyes. Even the outstanding students of the Academy were cordially received by Li Er, the dean of the Academy

Therefore, in the face of these famous scholars, scholars, eminent monks and many officials in Chang\'an, the students did not show timidity.

However, the students of the academy are only Mongolian children aged six or seven after all. Even if the doctors and teaching assistants of the academy have been maintaining order, they can not help whispering and whispering to each other, making the auditorium of the Academy very noisy.

When Li forget you appeared on the podium of the Academy auditorium, the noisy auditorium suddenly quieted down. Everyone stood up respectfully and bowed to Li forget you.

Even those famous scholars, scholars and eminent monks with white hair and beard, like the teachers and students of the Academy, all stood up respectfully, held their disciples\' rites and bowed to them, which made Li forget his worries feel a little uncomfortable.

Like the pupils of later generations, these great Confucians sat solemnly back on the futon on the floor, spread paper and pen in front of them, and listened carefully and were ready to take notes at any time, which made Li forget worry feel ashamed.

But to be honest, it\'s such a feeling of being respected. In fact... It\'s cool!

The sullen man restrained his mind, coughed and started today\'s course.

Crowded into the auditorium of more than 2000 people, it suddenly became silent. Everyone was absorbed and listened carefully.

"Zhu Sheng, we learned about the composition of light in the last class. I\'m going to teach you what temperature is in this class?" Li forgot to worry as he said, turning around and writing the word "temperature" on the blackboard behind him.

The reason why he is going to teach about temperature today is that he wanted to explain the plateau temperature with Li Er a few days ago, but he can\'t speak.

Since ancient times, it is too unscientific to describe temperature only by subjective words such as cold, cold, cool, warm, hot and hot.

He wanted to get the thermometer out, but it was difficult for a skillful woman to cook without rice.

Without glass, it is difficult to carve and polish a thermometer by relying on crystal. Therefore, the thermometer is only a resentment in Li\'s heart.

But unexpectedly, he spent a lot of money and invited those craftsmen who fired glass to bring great good news a few days ago.

According to Li\'s instructions, they used quartz sand and added soda and lime to burn a transparent object like crystal.

After the craftsmen presented their achievements, Li forgetful and Su Changqing were immediately surprised.

Glass!

Li Qieyou dared to bet that the fist size, transparent irregular crystal in front of him, if it weren\'t for glass, he would immediately crash into the tofu.

Su Changqing was equally excited, holding the piece of glass that was not beautiful, and in which there were many bubbles, he looked up and down carefully. It\'s like a valuable diamond in her hand.

In fact, it is not wrong to regard it as a "diamond".

Being able to burn glass in Datang is even more valuable than a diamond mine!

Since Zhang Qian emptied the western regions, the glassware produced by the Roman Empire began to be introduced into the Central Plains in large quantities, which was a luxury for the nobles.

The value of glassware introduced into the Central Plains through the silk road can be exchanged for gold of the same weight.

But in this era, no matter the Persians or the Roman Empire, the glass made is not so pure and transparent.

In Li\'s house, there are also "imported" glassware sent as gifts. From the critical point of view of him and Su Changqing, these glasses are far from those of later generations, at most between glass and colored glass.

Glass was difficult to burn in ancient times, mainly because the melting point of sand was too high.

With today\'s technology, it is very difficult to reach such a temperature.

However, Li forgets to worry that adding soda to the sand can reduce its melting point to more than 800 degrees. However, the glass burned in this way is a disposable product and will dissolve with water.

Therefore, lime needs to be added to it so that the fired glass can be used.

This knowledge was dug out of various pieces of knowledge in their memory after Li forgetful and Su Changqing almost wanted to break their heads and discussed with each other.

Now the craftsmen really use this method to burn transparent and colorless glass, which naturally makes them overjoyed.

As for glass blowing, in fact, these craftsmen who fired colored glass in the Tang Dynasty can do it. There is no need for Li forgetful to show off his shallow common sense.

Glass blowing was invented by the ancient Egyptians as early as 1000 BC. Later, the Romans learned this technology and spread it to the Central Plains with the introduction of Western glassware into China.

Li was overjoyed to learn that the craftsmen even knew how to blow glass. He immediately ordered the craftsmen to blow some glass tubes for him to make thermometers.

Below the glass tube, there is a circular sphere.

Fill the glass tube with mercury, and then close the nozzle with liquid glass. A thermometer is made.

As for measuring the temperature, it is not difficult to mark the temperature on the thermometer.

Boiling boiling water is 100 degrees, ice water mixture is zero degrees, and the middle is divided into 100 equal parts.

A thermometer that is not a standard but is sufficient to measure the approximate temperature is considered to be completed.

It is precisely because of the thermometer that Li forgot to worry about temporarily modifying his plan and preparing to popularize the concept of "temperature" in Datang in advance.

"We all know that water is hot and cold, and the weather is hot and cold. But have you ever thought that there are units of measurement for length and weight, and why can we only express cold and heat in terms of temperature, hot and cold? Everything should have a degree. Therefore, the Taoist ancestor called the degree of cold and heat as temperature! What I want to teach students today is temperature!"

Li\'s words about forgetting to worry fell into the ears of many college students, but they didn\'t feel much. After all, they are still young and have little knowledge. They don\'t understand the mystery.

However, the famous scholars, scholars, eminent monks and officials who were listening in were shocked and could not help straightening their backs