A: It's called Kongming Lantern. First of all, the sky lantern looks a bit like the hat worn by Mr. Kong Ming. Second, it is said that when Kongming was besieged by Sima Yi, the whole army was at a loss. Zhuge Liang came up with a clever plan and ordered people to take thousands of blank sheets of paper and paste them into countless sky lanterns. Then, they are taken away by the upward smoke attraction, and the sky lanterns rise one after another. Another person in the camp shouted: "Mr. Zhuge, the sky lamp is broken!" Sima Yi actually believed it and was cheated. This plan saved Mr Zhuge's life.

Q: What are Kongming lanterns used for?

A: Modern people often regard Kongming Lantern as a blessing. The wishes of men, women and children to write blessings by hand symbolize the bumper harvest and happiness every year. So it is also called wishing lamp or sky lamp! There are many folk customs in many places. When you get married and have children, you should light the lamp of peace! Sky lanterns can be used to organize spring outing parties, weddings, birthdays, festivals and young people's dates to show their love and advertisements.

Q: Why does this lamp fly into the sky?

A: The principle of Kongming Lantern is the same as that of modern hot air balloon. The air in the lamp is heated and expanded due to combustion and is taken away. But why does hot air float? We can use Archimedes principle to explain that when an object has the same volume as air, but its weight (density) is less than air, it can fly, which is the same as the buoyancy of water. When the air in the ball is heated, due to the expansion of the air, part of the air in the ball will flow out of the ball, making the density of the internal air less than that of the external air, so that the ball filled with hot air will fly.