20 years of teaching

Chapter 99 What is Physics

All of them pricked up their ears, they didn't expect so much knowledge of physics to be blown out between blows and blows.

It was quite hot in the classroom. At this time, Lin Feifan noticed that Wang Jiaxin, the class monitor, was fanning his face with an exercise book and said, "Wang Jiaxin, stand up."

Wang Jiaxin quickly put down the exercise book and stood up in a panic.

In the first physics class, I was a little flattered to be called out by such a handsome teacher.

Just use the exercise book to fan the wind, do this little trick, is it possible to be criticized?

Do you still want to stand still?
Lin Feifan said kindly, "Student Wang Jiaxin, please do what you did just now."

It turned out to be to assist the teacher to do experiments together.

Wang Jiaxin immediately understood, picked up the exercise book with a smile, and quickly fanned the wind towards his face.

The wind blows her hair flutteringly, and her youthful face is especially beautiful, full of compelling vigor.

"How does it feel?" Lin Feifei asked.

"Cool!" Wang Jiaxin shook her head, enjoying herself.

"Can you answer the specific reason?" Lin Feifan asked.

Wang Jiaxin stopped fanning, stuck out her tongue, frowned and thought for a while, and replied: "This is the phenomenon of heat absorption by evaporation, because... because the speed of evaporation is related to the speed of air flow near the surface of the liquid, I fanned it, The faster the air flow, the faster the evaporation and absorb more heat, so it feels cooler."

"Very good. The wording is scientific and standardized. It is completely correct. Full marks! Please sit down." Lin Feihua clapped and said.

"This is fanning someone's face, not a water fan." Some students muttered.

Lin Feifan heard doubts and asked a question by the way: "When describing women as gentle, they would say that women are made of water. May I ask students, what are men made of?"

Wow wow wow, that's really interesting!

The issue of men and women is also discussed in physics class, which is my favorite discussion.

"Men are made of iron."

"It's not iron, it's steel."

"Men want steel, and only women like steel."

"It's made of mud."

"Meat, firm lumpy meat."

"Ms. Lin made it with pimple meat, and the fat cat in our class is made with fat,"

……

After the students discussed for a while, Lin Feifan said, "Actually, we men are also made of water."

The deliberate gentleness of the voice makes goosebumps all over your body.

Hahaha……

Everyone in the classroom was excited, so excited!

Lin Feifan waved his hand to signal everyone to be quiet, and said, "The water content of a normal adult's body accounts for 70% of the body weight, and the water content of infants and young children can be as high as 80%. The surface of the human skin contains a lot of water. The wind will naturally speed up the evaporation of water. This is also a way for our body to regulate body temperature. When you exercise, you will sweat, and the sweat will evaporate and absorb heat, which acts as a cooling effect, so that the body temperature will not rise excessively and will maintain a constant temperature. Stable state. We should drink plenty of water every day to make up for the water lost by the human body, especially after exercising, we must replenish water in time, 360 days a year, and we must take the initiative to replenish water. Don’t wait until you are thirsty to drink water. Drink water when you are thirsty Watering is equivalent to watering after the seedlings have been wiped out, it will be too late, and the damage has already been caused.”

The classroom became very quiet again, which seemed quite practical.

"In fact, physics is not far away from us, it is very close to us, and it is closely related to our lives." Lin Feifei raised his hand and touched the Adam's apple, "When we touch this place and talk, we will feel the vibration, which means that the sound is produced by the vibration of an object."

Ahhh.

quack.

Haha.

……

……

All kinds of strange voices rang out in the classroom, and everyone touched their throats.

"Okay, everyone stop shouting now, and continue to listen to me." Lin Feifan patted the desk, motioning the students to quiet down, "The sound came out, how did it reach your ears? I don't emit light, but you Why can you see me? We are in a colorful world. Sunlight is white light. How can it be decomposed into different colors of light such as red, orange, yellow, green, blue, indigo, and purple? There is also an installation in this classroom The light bulbs and all the electrical appliances in our homes are what we study in physics class, and the thermal aspects we talked about earlier, and the mechanical aspects that we will learn later, are also part of the study of physics. So, what is physics?"

All the people looked at the teacher intently and listened with great interest, but when the teacher asked questions, they all lowered their heads.

What is Physics?This question is too deep.

Lin Feifan asked with a smile: "What is Chinese? What is mathematics? What is English? And how are subjects such as politics, history, geography, music, and physical education defined?"

Everyone looked at each other in blank dismay, pinching their fingers and counting carefully. They have all studied Chinese and mathematics for seven or eight years. They really don’t know what is Chinese and what is mathematics. The Chinese teacher and the mathematics teacher have never talked about it.

Lin Feifan turned around and wrote a line on the blackboard.

【Physics is a science that studies the laws of various physical phenomena such as sound, light, heat, electricity, and force, and the structure of matter. 】

A few students were taking notes, but most of them didn't start writing. They looked at the teacher happily, waiting for the teacher to talk about something more interesting.

"Take notes, the definition of physics in textbooks is not so detailed." Lin Feifei tapped on the blackboard and reminded, "This is the only knowledge point that I ask students to memorize in this class. Can you do it?"

"Yes!" The voice was very uniform and loud, and then he quickly picked up the pen and took notes.

……

……

Lin Feifei further added: "Physics is not only interesting, but also allows us to see the world more clearly. There was a breakdown and there was a power outage, and we were able to use what we learned about electricity to figure out why and solve the problem pretty well.”

"Biao... Biao... Mr. Lin, after finishing junior high school physics, can we work as electricians?" Yao Xiaodong raised his hand and asked.

"Theoretical knowledge is enough, and the proficiency in operation needs to be strengthened." Lin Feifei glanced at Yao Xiaodong, then glanced at the whole class, and said loudly, "Your goal is not just to be an electrician, you have to establish lofty ideals , To become a scientist, use what you have learned, make great inventions and create, and make contributions to the country.”

Lin Feifei paused and asked, "Do you know which discipline has made the greatest contribution to mankind in the [-]th century?"

"It must be physics." There were almost no objections in the classroom.

Some people have heard of this problem before, and those who have not heard of it can guess it.

When the physics teacher asked this question, he definitely wanted to emphasize the role of physics.

With a serious expression, Lin Feifei said solemnly: "In the entire 100 years of the twentieth century, no subject can compare with physics in terms of benefiting mankind. The invention of generators and electric motors, electric lights, telephones, Various electrical appliances such as televisions and refrigerators, steam engines, diesel engines, gasoline engines, rocket engines, modern information technology, aerospace technology, nuclear technology and other great inventions and creations are all fruits of the painstaking efforts of physicists. It can be said that there is no physics Without the contribution of science, there would be no modern human civilization, and we would not have the beautiful and happy life we ​​have today.”

So tall!
A newly opened physics course involves so many new things and great achievements of scientists.

The classroom was quiet, and the previous excitement on everyone's face turned into longing and yearning.

(End of this chapter)