I thought that this New Year would be deserted in the prison, but I didn't expect that someone came to the prison on the morning of the fifteenth day of the first month, and it was not relatives, friends and family, but palace attendants.

I didn't say anything, just said that the emperor summoned Wu Yuanqing into the palace to watch the ceremony.

Ceremony?

Wu Yuanqing was a little confused, I haven't heard of any major political events recently, even if today is Shangyuan Festival, the fifteenth day of the first month, there is no need to do any celebrations, not to mention that his current identity is still a prisoner.

After asking more questions, the chamberlain shut up and did not speak. I entered the palace in a daze and came to the outside of the Taiji Palace, and saw from a distance that there were many people in the empty field around a huge thing covered in colored silk and busy.

didn't have time to take a closer look, followed the inner attendant and already came to a side hall, there was no one in the side hall, and Wu Yuanqing was not closed by the inner attendant from the outside after entering.

I'll go, didn't Nima come to watch the ceremony, why did he lock up Lao Tzu again, and changed from the prison to the palace, is this Nima considered a felon, detained in a different place? You can't be locked up in the palace.

was locked up in this palace for half an hour, and when it was almost noon, the chamberlain came to release Wu Yuanqing, and then took him to the outside of the Taiji Palace.

Before, some people were still busy from a distance, but now they are still busy here, but there are more civil and military officials, as well as concubines, princesses, princesses, and even the emperor Li Yuan, who has not appeared for a long time, has appeared on the high steps.

And when he got closer, Wu Yuanqing finally saw the true face of Lushan with the huge thing that had been removed from the tarpaulin.

"I'll rub, this Nima is...."Wu Yuanqing's surprised words were not finished, and he was already laughing behind him and took over his unfinished words and said: "Hot air balloon, I made it. Well, to your surprise, I didn't think I could actually do it."

With the words, Li Tai's chubby fleshy face appeared in front of Wu Yuanqing.

Air has mass, and the volume of hot air is greater than that of cold air with the same mass. In other words, the mass of hot air is lighter than that of cold air for the same volume.

To put it simply, the hot air is lighter than ordinary air, and the hot air will rise automatically.

This is a knowledge point that Wu Yuanqing talked about when he taught physics to Li Tai before, and told him that if he knew this, he could create a device that made people fly to the sky.

And the possibility of being able to fly to the sky is also the most important reason why Li Shimin was willing to let Li Tai learn from Wu Yuanqing.

For the flying sky, the ancient Chinese have been tirelessly pursuing.

In addition to the mythical gods ascending, the ancients were also making tools that could fly to the sky.

Legend has it that the carpenter's grandfather, Lu Ban, according to "Mozi. Lu Wen recorded: "The male loser cuts bamboo and wood for kites, and flies into it, and it does not fall for three days." Pen? Interesting? Pavilion wWw. ｂiquge。 ｉｎfo

Of course, the exact facts of this are unknown, maybe it is true, or maybe it is just a legend.

However, it can be seen that the sages who made things that could fly into the sky began to experiment a long time ago.

In addition to this unknown wooden bird, the ancient Chinese also invented many flying tools. For example, kites, after Cai Lun improved papermaking in the late Eastern Han Dynasty, there were kites made of paper, called "paper kites", and by the time of the Northern and Southern Dynasties, kites began to become a tool for transmitting information.

In addition to kites, there are also Kong Ming lanterns, commonly known as wishing lanterns, also known as prayer lanterns, which are often used to fly and pray for blessings in later generations.

But the early Kong Ming lanterns were used to convey messages in the military. The origin of the Kong Ming lantern is said to have been invented by Zhuge Liang during the Three Kingdoms. Back then, Zhuge Liang was besieged in Pingyang and could not send troops out of the city for help. Kong Ming calculated the direction of the wind, made a floating paper lantern, tied a message for help, and escaped the consequences of the danger, so later generations called this kind of lantern Kong Ming lantern.

There is also a kind of bamboo dragonfly, a toy that Chinese children often play with, which can also be classified as a flying machine invented by the ancients.

The bamboo dragonfly was made by the Chinese in 500 BC and has been a toy in the hands of Chinese children for more than 2,000 years. It was introduced to Europe in the eighteenth century, inspiring people's thinking, and George Kelly, an Englishman known as the "father of aviation", was fascinated by bamboo dragonflies all his life. His first aeronautical research was in 1976 when he imitated and modified the "Bamboo Dragonfly", and thus realized some of the working principles of the propeller. His research drove the development of the aircraft. And brought inspiration to Western designers to develop helicopters.

These are all to make objects go to heaven, and the first one to make people go to heaven is to talk about the ten thousand households of the Ming Dynasty.

Wanhu is a personal name, a celebrity, and an official name. Wanhu's original name was Tao Chengdao, he used firearms to help Zhu Yuanzhang who was still the king of Wu to open the world, and Zhu Yuanzhang awarded him Wanhu official with the yuan system.

In his later years, Tao Chengdao tied forty-seven homemade rockets to a chair, sat on them, held two large kites in both hands, and then asked someone to light and launch. It was envisaged to fly using the thrust of the rocket, coupled with the power of the kite. Unfortunately, the rocket exploded, and Wanhu also gave his life for it.

Tao Chengdao was the first person in the world to think of and implement the use of rockets to fly into the sky, although his efforts failed, but his idea of lifting off with the help of rocket thrust was the first in the world, so he was recognized by the world as the "real ancestor of spaceflight". In order to commemorate Tao Chengdao, the ancestor of the world's aerospace industry, the world's scientists named a ring volcano on the moon "Wanhu Mountain".

These all prove the ancients' yearning for flying, Wu Yuanqing told Li Tai about the principle of the Kongming lantern, and casually said that it is possible to realize the dream of flying by making a large enough device according to the Kongming lantern.

Wu Yuanqing just said it casually, but he didn't expect Li Tai to really put it into action. In the past two years that he has been away from Chang'an, Li Tai has been researching, starting with the Kong Ming lantern at the beginning, and then making it bigger step by step, and then trying to carry things under the Kong Ming lantern. From a pen at the beginning, to a bag of pastries later, to a heavier stone.

Kong Ming's lantern is getting bigger and bigger, and he is carrying more and more things, and Li Tai is also encountering more and more problems.

The first is the tightness of the paper, with the larger the Kong Ming lantern, the worse the sealing, and due to the size of the paper, the larger the Kong Ming lantern, resulting in more places where the paper needs to be glued and pasted. If the sealing is poor, the hot air cannot be completely contained, so the upward buoyancy exerted by the hot air to the Kong Ming lantern is insufficient.

If the buoyancy is insufficient, the things that can be carried will not be heavy, otherwise they will not be able to fly high, or even fly.

Another is the thing that is heated underneath, generally because of the small size and light reason of the Kong Ming lantern, the lower side is lit and heated with pine resin, and it can be lifted into the air.

But the back of Li Tai's Kong Ming lantern is getting bigger and bigger, and simple heating of pine resin is no longer enough to make it rise into the air.

For this reason, Li Tai was so worried that everyone lost weight.