Was the Kongming lantern in the Lantern Festival custom really invented by Kongming?

"Mom, look! These lanterns can float up to the sky!" Xinxin pointed at the TV screen and shouted, "How spectacular and beautiful!"

"Haha, that's a Kongming lantern, also called a sky lantern. On the fifteenth day of the first lunar month, the Lantern Festival, people will release sky lanterns to pray for blessings. This custom exists in many places in our country." Mom explained.

"Why is it called Kongming Lantern?" Xinxin asked curiously.

"There are two versions about the invention of Kongming lanterns. One is that during the Five Dynasties and Ten Kingdoms period, a woman named Shen Qiniang, who followed her husband to fight in Fujian, used bamboo strips to make a square frame, pasted paper on it, and made a large lantern. She placed burning rosin on the chassis and it would fly into the sky. The shape of this rosin lantern is very similar to the hat worn by Zhuge Liang during the Three Kingdoms period, so it is called Kongming lantern." Mom introduced, "The other version is naturally that it was invented by Zhuge Liang during the Three Kingdoms period. It is said that Zhuge Liang led his army to an expedition and was besieged in Pingyang by Sima Yi. In order to solve the dilemma, Zhuge Liang invented this lantern and set it off in the sky to attract the attention of the Wei army. When the Wei army led troops to chase the lantern, the Shu army was able to escape. Zhuge Liang, whose courtesy name was Kongming, later generations called this lantern Kongming lantern. Regardless of which version is true, Kongming lanterns were actually used for military purposes at the beginning."

"Then when is it used for praying?" Xinxin asked.

"Well, probably during the Qing Dynasty. At that time, many people in mountainous areas would hide in the mountains when bandits robbed them. When the bandits left, the people who stayed behind would release sky lanterns to represent safety! So the sky lanterns changed from alarm signals to safety signals, and have evolved into the use of praying for blessings today." Mom explained, "In many places, during the Lantern Festival, people will write their wishes on lanterns and release them into the sky, praying that their wishes will come true. This is called releasing sky lanterns."

"But aren't lanterns made of paper? Won't they catch fire? And besides, lanterns can't just fly into the sky by lighting a candle, right?" Xinxin had so many questions!

"Haha, there are so many questions! Then let me tell you about the method and principle of making Kongming lanterns." Mom smiled and touched Xinxin's head. "The structure of Kongming lanterns is roughly divided into three parts: the main body, the bottom ring and the fuel. The main body of the Kongming lantern is the lampshade. Since ordinary paper is not resistant to high temperatures and can be easily ignited, the main body of the Kongming lantern needs to be made of flame-retardant paper; the bracket of the base of the Kongming lantern is generally made of bamboo grates or iron wire. Generally, Kongming lanterns are cylindrical with the opening facing downwards; finally, the most common fuel for Kongming lanterns is small white wax blocks made of asbestos and wax oil."

"So what is the flying principle of the Kongming lantern?" After understanding the structure, Xinxin repeated the question in her mind before.

"The principle of how a Kongming lantern is launched is the same as that of a hot air balloon. When a Kongming lantern is lit, the air inside the lantern will expand according to the principle of thermal expansion and contraction, and some of the gas will flow out of the lantern, making the density of the air inside the lantern less than the density of the outside air. As the density decreases, the total weight of the lantern becomes less than the original buoyancy, so it will rise!" Mom explained with a smile.

"Oh, I understand. At the beginning, the Kongming lantern is full of cold air, which is heavy and naturally cannot fly. But after being heated, the hot air makes the Kongming lantern lighter, so it flies!" Xinxin repeated the principle with understanding.

"Yes. The invention of the Kongming lantern was much earlier than the hot air balloon. It can be said that the ancients had a lot of experience in studying 'flying vehicles'!" said my mother with a smile.

【Knowledge Card】Flying Lantern

Every year during the Lantern Festival, many places in my country have the custom of writing blessings on sky lanterns, lighting them and releasing them into the sky. This sky lantern that carries people's wishes is called the Kongming Lantern.

There are two theories about the origin of Kongming Lanterns: one is that during the Five Dynasties and Ten Kingdoms period, Shen Qiniang released sky lanterns as a military communication signal, and the lanterns were named because they looked like Zhuge Liang's hat; the other is that when Zhuge Liang was besieged in Pingyang by Sima Yi, he invented Kongming Lanterns to attract the enemy's attention. Regardless of which theory, Kongming Lanterns were first invented for military purposes. Later in the Qing Dynasty, people used Kongming Lanterns to report safety, and from then on, they gradually became used for praying for blessings.

The principle of a Kongming lantern is the same as that of a hot air balloon. When the air inside the lantern becomes hot due to combustion, according to the principle of thermal expansion and contraction, the volume of the hot air expands, and part of the gas is discharged from the lantern, causing the gravity to be less than the buoyancy, causing it to rise into the sky.