Chapter 19 Section 19

"Although the basic principles of anti-aircraft fireworks and climbing fireworks are similar, there are actually subtle differences. Speaking of it, anti-aircraft fireworks are actually a kind of cannon. Look at this straw." Tang Chuan held his chopsticks with his fingers Refers to the straw that Gong Ping uses to drink Coke, "You rub the small corner of the napkin into a paper ball and stuff it into the straw, and if you put your mouth to the end of the straw to blow, the small paper ball inside will suddenly come out of the straw. The other end of the straw flies out. As for anti-aircraft pyrotechnics, when the pyrotechnics are installed on the cylindrical launching platform, the gunpowder for launching is loaded under it. With the help of the impact force and air pressure during the explosion, the pyrotechnics In contrast, climbing fireworks use the reaction force of self-detonation and backward ejection of sparks to fly upward. The compressed air and water inside the plastic bottle rocket play the role of gunpowder.”

Yu Chuan kept talking, and the chopsticks in his hands and his mouth also kept moving.Not afraid of choking.Compared with the content of Yu Chuan's words, Kyohei felt that Yu Chuan's actions were more attractive to him. "According to this, the ones we bought just now are not anti-aircraft fireworks, but climbing fireworks?" "That's right. Real anti-aircraft fireworks are beyond the reach of ordinary people. They are governed by the Gunpowder Ban Law, so if you don't have a qualification as a pyrotechnician, you can't buy them." "Ok." On the way back from the beach, the two stopped by a convenience store to buy some fireworks.It's not that Gongping asked Tang Chuan to buy it, but he mentioned that he and his uncle went out to set off fireworks the night before, and Tang Chuan took the initiative to buy some.

After eating the omelet rice, Kyohei was drinking coke, when suddenly, the sliding door of the room was opened, and a man in a hat and navy blue clothes came in to have a look. "Ah, excuse me." The man immediately closed the sliding door. Gongping blinked: "What did that person do just now?" "Looking at the uniform he was wearing, he should be a police appraiser. It seems that they are still investigating the situation." Tang Chuan said. Not long after, Cheng Shi entered the house with tea.Sorry to surprise you just now.Cheng Shi apologized to Yu Chuan. "The police are here again? What the hell are they investigating?"

"Not sure. But they seem to be investigating the source of the fire." "Fire source?" "They went into the kitchen to see if the stove was on." "That's very strange. Didn't they come for that accident in the rocky field?" "No, they said, that's what they came to investigate. It's just that they don't want to say what they did." Tang Chuan took a sip of tea and said, "Well, this is their usual style of doing things." After dinner, the two decided to go out together to set off fireworks.Walking out of the banquet room, a group of people wearing the same clothes as the man just now were wandering around the hotel.

Kyohei and Yukawa walked to the entrance together.He knows where the barrel is. Gong Ping.Someone called Gong Ping.Looking back, I saw that the stairs leading to the basement were open, and Chongzhi walked up the stairs. "Going to set off fireworks?" "Yeah. Lend me the bucket." "It's okay, you can take it..." Shigeji's gaze stayed on the plastic bag in Tang Chuan's hand, "Huh? There seem to be some high-firing fireworks?" "To be precise, it should be climbing fireworks. Can't it?" Shigeji smiled wryly, touched his bald head, and looked at Yukawa.

"We set it off secretly that night. There will be regulations in the town, saying that this kind of fireworks must be set off by the sea. People from the fire department have also come to guide them. Normally, I would not be so stubborn, but tonight……" "I see. It will be troublesome if you go to the neighbor's house. Then, these climbing fireworks will not be released for the time being." Hearing what Yu Chuan said, Kyohei also nodded. Walking out of the hotel, the two walked around to the back of the house.Behind the house is a clearing, and behind the clearing are trees.

Kyohei was about to ignite the small fireworks that were set off in hand, but Yukawa stopped him. "Wait. Do you know how fireworks go off?" "Hey? Isn't it just stuffing a lot of gunpowder inside?" "If it is true as you said, as long as there is a fire, the fireworks will explode." All right.As he spoke, Tang Chuan took out something white from his pocket.After a closer look, I realized that it was a ball of cotton.Tang Chuan put the ball of cotton on the ground, and then took out nails and sandpaper from the other pocket.He rubbed the nail with sandpaper on the cotton, and after a while, the cotton was covered with black iron powder.

"I'll light it up." Tang Chuan moved the disposable lighter in his hand to the cotton. In an instant, the cotton was burning while emitting sparks.Wow.Gongping cried out loudly. "Even metals that are usually incombustible can be ignited when this condition is met. The true face of fireworks is actually metal. It is made by mixing several metals together." "Why mix several metals together?" "Good question. Okay, light the fireworks first." Tang Chuan handed the lighter to Gongping. Kyohei lit the handheld fireworks.In an instant, colorful flames radiated from one end of the fireworks.As time goes by, the color of the firelight gradually changes.

"The blue ones are copper, the green ones are barium, the red ones are strontium, and the yellow ones are sodium. They're all metals. Like this, a certain metal or metal compound, when burned, emits a characteristic characteristic of that substance. This is called the flame reaction." Yu Chuan's light tone was in stark contrast to the gorgeous sparks of the fireworks, "Fireworks uses this—" Having said that, Yu Chuan suddenly stopped and looked up. Two men in Appraisal uniforms are descending the emergency stairs at the back of the building.Seeing Kyohei and Yukawa, they both nodded and greeted formally.

"Where did they go up? Didn't realize it before." "Probably went up to the roof. Isn't the chimney over there?" Among the two appraisers, the one wearing glasses walked up to Kyohei and Yukawa. "Sorry for disturbing the interest of the two of you. Are you a resident here?" The man asked Yu Chuan. "yes." "May I ask you a few questions?" As he spoke, the man stretched his hand into his chest pocket. "I know the two are police officers. What do you want to ask?" Tang Chuan asked. "Did you stay at this hotel the day before yesterday?"

"Yes. I checked in the night before." "I see. When you were staying in this hotel, did you notice anything strange?" Tang Chuan had a puzzled expression on his face, as if he didn't quite understand what the other party meant. "I have heard it said that a traveler here fell to the rocks and died." "No, I'm not talking about that. I just want to ask you, has there been any strange things in this hotel recently? For example, you suddenly feel sick when you stay in the room, or you smell a strange smell some type of." "Disgusting? Smell?" Tang Chuan thought for a while, "I don't remember it." "Really? Okay. I'm sorry to bother you." The man turned around and was about to leave. "Don't you ask him?" Tang Chuan said.Hey?The man turned back. Tang Chuan looked at Gongping next to him, and continued, "It doesn't seem very theoretical if you don't ask the child about the situation?" "Ah. Hmm..." The man looked puzzled, and put his face in front of Gongping, "What about you? Have you ever encountered any strange things?" Gongping silently shook his head.The man nodded, saluted Tang Chuan, then turned and left. Tang Chuan raised his head and looked at the building in front of him.After that, he nodded and asked Gongping, "Where did we talk just now?" "Principles of the color change of pyrotechnics." "Okay. Then let's talk about the principle of the snake-shaped fireworks." After speaking, Tang Chuan reached into the plastic bag and searched for a while.