As soon as the stupid big man said this, the big girl was busy pulling him next to him: "Silly big man, Brother Guo told us about the pressure of water before, the deeper the bottom, the greater the pressure, the bottom of the nine oceans is afraid that it must not be thousands of meters deep, the pressure of the water is extremely huge, and the big black will really be pressed into a meat patty." ”

Guo Dalu glared at him stupidly: "You kid, you must not have listened to the class well that day, and you don't know how to review when you go home, so you will be punished for going back and reciting the pressure of water chapter 500 times!"

The black bear spirit looked at Guo Dalu: "The pressure of the water? What is that? I know that there is great power in the depths of the ocean bottom, and that is because I have dived to the bottom of the sea and tried it myself, you are just an unknown cultivator in this poor and remote land, how do you know about this? When a cultivator enters the sea, he usually uses the trick of secluded water, and the sea water cannot touch his body, unlike me and other monsters, who enter the sea in the flesh, so he does not know the magical power of the sea. ”

Guo Dalu put on a picture of a master in the world: "I know what is so strange about water pressure, and I also know that there is pressure in the air." Using air pressure, I can make ordinary people fly in the air, and even travel thousands of miles in the air in a day. How's it going? You know how good I am, why don't you quickly recognize me as the master?"

The black bear spirit laughed: "You mountain and wild cultivators, you are really talking nonsense, this qi runs between heaven and earth, everywhere, how can there be any pressure, pressure." If the qi is also strong, then if we stand under the nine heavens, will we still be carrying the nine heavens? Look at this ground, there are ants crawling everywhere, is it possible that even this ant is carrying the nine heavens, if this is the case, this ant has not been flattened earlier?"

Guo Dalu sighed: "You bear spirit, I pity you for your successful cultivation, you can be a person, and you have no blood debts, so I will say a few more words to you, but you are so ignorant." That's it, I'm going to show you the magic power of science!"

Brother Hao, Da Niu and even Chen Qingdai, etc., all looked at Guo Dalu curiously, Guo Dalu had only talked about water pressure before, but he hadn't talked about air pressure, water pressure was actually easy to understand, put a cup of water in his hand, feel the weight in his palm, you can understand that water also has pressure, drilling to the bottom of the water is like carrying the water on his back, but this gas is unpredictable, where does the pressure come from.

Guo Dalu beckoned to the second and third girls: "Do you know how to make Kong Ming lanterns?"

The second girl and the third girl nodded: "During the Tangram Festival, our daughter's family will put river lanterns, put Kong Ming lanterns, use the lightest bamboo paper to make Kong Ming lanterns, and after lighting the fire, you can fly to a very high place in the air." Whose daughter makes Kong Ming lantern the highest and farthest, then her wish written on the paper will be heard by all the gods and help her achieve her wish. The eldest sister made the best Kong Ming lantern and flew the highest. "--Kong Ming in the mouth of the second and third girls is not Zhuge Liang, but a skilled craftsman named Kong Ming in the Great Li Dynasty, and this flying lantern was invented by him.

The speaker has no intention, the listener has a heart, and the big girl blushed next to her: "Brother Guo asked you something, what are you doing with me." The reason why she lost her temper was because during the Tangram Festival, the Kong Ming lantern she made with her own hands had a person's name written on it, the name of a black young man who brought a new life to Houlong Village. I don't know if the gods in the sky saw this lamp and had a kind heart to help her achieve her wish to spend her life with that person.

Where did Guo Dalu know this little child's thoughts, he said: "You just make a Kong Ming lantern, don't be too exquisite, as long as you can fly after ignition." ”

The second girl and the third girl are really skillful, and soon pasted a Kong Ming lantern, although Guo Dalu told not to be too exquisite, but the girl's family loves beauty, and wants to show off in front of everyone, the Kong Ming lantern is hung with tassels, and the bamboo paper also uses a pencil to outline the eight immortals across the sea, this lamp is put in the air, and it turns in the wind, like a marquee.

Guo Dalu didn't pay attention to the subtlety of Kong Ming's lantern at all, and really called the pretty eye to show the blind man, he took the lamp, held it in his hand, and said to the black bear: "Does this thing have weight?"

The black bear spirit opened his eyes like little black beans: "Are you a loose cultivator, deliberately playing tricks on my old bear?" Although this lamp is delicate, it is also made of bamboo strips and paper, and there are candles in it. ”

Guo Dalu nodded: "It turns out that you actually gave yourself a surname, surnamed Xiong, I said, why don't you have the surname dog, it seems that although you are a mountain and wild monster, you also know what is good, and you don't want to give yourself a name that you don't like." Since you know the shame, you can't deliberately dismiss it when you see the subtlety of my scientific knowledge. ”

The black bear spirit said angrily: "My old bear is also a cultivator, since he was born in his mother's womb, he has obtained the essence of the sun and the moon, and he has cultivated qi and spiritual wisdom, why did you humiliate me? What trick do you want to play in front of me, do it quickly." If it makes sense, I'll submit myself to you. ”

Guo Dalu didn't say much, and handed the Kong Ming lantern to the second girl: "Light the fire and put the lamp." ”

The second girl lit the fire neatly, held the Kong Ming lantern in her hand, and in the flickering light of the candle, the Kong Ming lantern floated gently, drifting higher and higher, and a gust of night wind blew, fluttering upward, turning into a red dot in the night sky.

Guo Dalu asked the black bear spirit: "Do you see it?"

The black bear spirit sighed: "Put a lamp, what's so beautiful, you put lights every year, some of the lights flew to Fengshen Mountain, fell down, ignited the grass and trees, and caused me to take my subordinates to fight mountain fires everywhere." ”

Oh, this black bear spirit is actually a volunteer mountain forest firefighter, Guo Dalu's impression of it is a little better, and he said patiently: "This Kong Ming lantern uses air pressure to fly into the sky." ”

The black bear spirit stared at Guo Dalu in a daze, suddenly burst into laughter, and slapped the ground with a bear paw: "You cultivator, you are really crazy! Crazy! This Kong Ming lantern is flying in the sky, and what air pressure does it have to do with Lao Shizi?"

Guo Dalu was not angry, and waited for the black bear spirit to stop laughing, and then said lightly: "You just admitted in person that Kong Ming Lantern has weight. ”

"That's right, my old bear naturally recognizes this sentence. ”

"The Kong Ming lantern has weight, so if it wants to fly, it has to have another force to carry it into the air. ”

"Well, that's, it seems to be the truth. ”

"Kong Ming Lantern is helpless, and it's not that I have used my mana, but the power to fly to the sky has another place. ”

"That's true. ”

"That's why I said, this power of flying comes from air pressure. ”

"Nonsense!

"Okay, then you say, where does this flying power come from?"

"Of course it's from--from--"

Guo Dalu and the black bear spirit asked and answered, and the children and villagers of Yixue next to them were also fascinated, Kong Ming lantern is the most common children's plaything, but no one has ever asked, why does Kong Ming lantern fly?

At this time, hearing that Ai Ai couldn't answer Guo Dalu's seemingly simple question, everyone also fell into deep thought, and Brother Hao rolled his eyes: "I know, it's the fire, it's the flame of the candle, and it flew up with the Kong Ming lantern." ”

The black bear spirit was thinking hard, and when he heard Brother Hao'er's words, he didn't care that he and himself were actually hostile, as if he had grabbed a life-saving straw, and said in a loud voice: "That's right! That's right! It's the flame of the candle." Before lighting a candle, the lamp doesn't fly, but when it lights a candle, it flies. That's right, that's the truth, haha, it's too simple, it's the flames flying, it's the flames flying!"

Guo Dalu said lightly: "Why do flames fly?"

The black bear spirit shouted, "Why does the flame fly? It, it could fly, yes, the flame could fly!"

Although Chen Qingdai fought with the black bear for a long time, she was tired and half dead, and she was punched several times by it, but she also nodded at this time: "The flame itself does fly, and I sometimes breathe fire - well, that is a fire, and sometimes there will be fireballs rising in the air, so this flame can really fly." ”

Guo Dalu put his hands behind his back: "In this world, birds that can fly have wings, and in addition, cultivators cast spells, but this flame has neither wings nor spells, why can it fly on its own?"

The group was dumbfounded, and the black bear spirit snorted, "You, you are quibbling! Flames can fly, it is an innate ability--" It spoke, its voice lowered, for even it knew that it could not justify itself. This flame is not a living creature, and the so-called innate ability is a big joke.

Guo Dalu said: "Let me tell you why this flame flies, and then fly into the sky with Kong Ming lanterns." Between heaven and earth, there is air, which I call air. Air not only has its own pressure, but also has the characteristics of cold air sinking and hot air rising. The candle flame in the Kong Ming lamp heats the air on the upper part of the lamp, and after the hot air rises, the cold air around it naturally squeezes over under the action of pressure to fill the position left by the rise of the hot air. This is why when the flame of the candle becomes smaller or even extinguished, the Kong Ming lantern will fall down, and even cause a mountain fire, because there is not enough hot air to heat, and the pressure of the cold air squeezed around is insufficient. ”

The people around were stunned, the knowledge involved in Guo Dalu's words was too difficult, and even the children who had learned the pressure of water were a little half-understood, but Guo Dalu's words were self-contained, and they could be called self-justifying, and they really couldn't find the problem.

The black bear spirit lowered his head and thought for a while before he said, "I can't understand a lot of what you said, but I can't tell what is wrong with it, it seems that there is really some truth." Because, apart from your words, I can't explain the reason why Kong Ming's lantern will fly. ”

Guo Dalu chuckled and said: "If you submit to my door, learn more scientific knowledge, and understand the principle sooner or later, in fact, if I get a hot air balloon, it will be more intuitive for you to understand the air pressure, well, there is also a vacuum ball, after that thing is pumped into a vacuum, under the pressure of the surrounding atmosphere, even if you and Da Hei pull together from both ends, you can't pull it away." How about you? Will you submit to me?"

However, the black bear spirit shook his head: "I don't want to be a human slave anymore, if you coerce me with the Natal Yuan Pill, I would rather die." (To be continued.) )