I Just Want to Be a Quiet Top Student

The teacher who taught undergraduates at Yanda Mathematics College said to Shen Qi, why are you still in class?

There is no horoscope at Princeton, and Shen Qi's current status is a bit embarrassing. He has obtained an undergraduate degree certificate in mathematics, but he cannot immediately enter graduate school.

Life seems to lack a little passion.

In all fairness, purely theoretical academic research is a boring thing, and after years of boring, it will not rest until death.

Shen Qi also wanted to know how to find some excitement and fresh energy in the long-term theoretical research.

Shen Qi needs to take the initiative and seek passion in the ordinary.

"Li Zhenqiang!" Suddenly, a professor on the podium yelled and reprimanded him severely: "What's the matter with you, a student, you sleep for a long time in my big biology class?"

Li Zhenqiang woke up suddenly with sleepy eyes: "I'm sorry, Mr. Sun, I was wrong!"

The old professor's face darkened: "My surname is Ren, not Sun! The one surnamed Sun is teaching you Gao Dai!"

After the high-level class, the first-year students of the Department of Mathematics took a college physics class in the same classroom, and the teacher was Ren Buqi.

Professor Ren is about to retire, but his temper is very hot: "I can't even remember the last name of the teacher, Li Zhenqiang, your usual grade is 0!"

Li Zhenqiang's name is very domineering, but his personality is not strong, so he admits to being cowardly.

The course of college physics is one of the compulsory courses in the Department of Mathematics. You have me in mathematics and physics, and you in me. It is difficult to draw a clear line between them. Falling in love and killing each other is the norm.

Ren Buqi is a professor in the School of Physics. He teaches college physics courses for non-physics majors.

Professors from the School of Mathematics also teach advanced mathematics courses for non-mathematics majors.

"The final exam will be next month. Your class of mathematics students is the worst class I have ever taught!" Ren Buqi was furious. The School of Physics of Yanda University is powerful, and the style of professors in this school is completely different from that of the School of Mathematics.

Shen Qi is very heartbroken, Professor Ren, you are too unreasonable. The average grades of our mathematics department students definitely beat your physics department. Compared with our physics department, they failed by a quarter in high mathematics. Don't ask me how I know, I have a source.

"And you, Shen Qi." After Ren Buqi scolded Li Zhenqiang, he continued to reprimand Shen Qi, "As a class monitor, your attendance rate in the big object class is less than 50%. If you are a class monitor, just quit." The teachers didn't care much about Shen Qi anymore, but the teachers of the Physics Institute cared about him.

"I really didn't play a leading role." Shen Qi expressed his apology. He was busy writing mathematics papers and defending his degree this semester, so he really didn't pay much attention to physics.

Now that he has a bachelor's degree certificate in mathematics, Shen Qi has made a plan to make great efforts to study physics and seek breakthroughs in the branch of mathematical physics.

"There are more than 30 people in your mathematics department, and the number of people attending this class is 15." Professor Ren's eyes were murderous, "Shen Qi, tell me what to do."

"Should I call them back to class?" Shen Qi asked tentatively.

"No need." Ren Buqi said coldly.

No need, just three words and ten strokes.

The meaning of it is understood by the students present.

"Okay, don't delay everyone's study time, continue to class." Ren Buqi paced back and forth on the podium, as if thinking.

After standing still, Ren Buqi made up a question: "Remove the desks, chairs, podium and all other items in this classroom, leaving only me and you, and ask us the total mass of these people, and the air quality in the classroom. What is the ratio? Just estimate it, it’s a compulsory question.”

Estimation is a method often used in physics. Generally speaking, it is not required that the estimated results be very accurate, and the difference in order of magnitude is enough.

There is often more than one method of estimation, and the method to master is simple and interesting, but if you can't turn your head, you will be at a loss.

This estimation question compiled by Professor Ren does not give any specific data, and asks what is the ratio of human mass to air mass in the classroom.

"It's kind of interesting." Shen Qi writes papers every day, and he gets irritable when he writes too many papers, and occasionally doing quizzes is also a way to adjust his physical and mental health.

Shen Qi quickly scanned the classroom, there were 16 human beings in total, including a teacher and 15 students. One woman, 15 men.

The height of the classroom is about twice the height of the human body, and it can be estimated from the number of vertical columns of tables and chairs in the classroom that the width of the classroom is about 10 times the width of the human body.

From the number of rows of seats in the classroom, including the number of additional rows converted from the podium area, it can be estimated that the length of the classroom is about 45 times the thickness of the human body.

Then, the volume of space occupied by the classroom is about 900 times the volume of a person.

Theoretically speaking, this small classroom can accommodate 900 people at the same time, according to the way of building blocks, until it is full.

Take 16 to 900 to get an estimate of the ratio of human volume to air volume in the classroom.

The volume ratio has been estimated, but a set of density data is needed to obtain the mass ratio.

So the question is, what is the appropriate value for the density of the human body?

People can swim in water, which means that the density of human body is similar to that of water.

The molar mass of water is 18, and the average molar mass of air can be approximately 30.

Considering the close packing of water molecules, the spacing of air molecules is about tens of times the size of air molecules.

Shen Qi finally estimated a value, 10.

It can be approximated that the total mass of 16 people in the classroom is 10 times the air quality in the classroom.

Shen Qi was a little surprised by this estimation result. Is the human being too light or the air too heavy?

The above observations and calculations were all completed in Shen Qi's brain, which took about 15 seconds.

"How much?" Shen Qi asked Ouye beside him.

"10." Ouye also relied on mental calculations to arrive at the estimated value.

That should be right, Shen Qi said to Ouye: "You come to answer Professor Ren's question."

Ouye raised his hand.

Professor Ren: "Ouye, you figured it out, so fast? How much?"

Ouye: "10."

Snapped!

Ren Buqi snapped his fingers: "Student Ouye has a quick mind and her attendance rate is close to 100%. You should all learn from her. That's right, the answer is 10. The combined quality of everyone in this classroom is approximately 10 times the quality of the air." We only need to estimate the approximation of the order of magnitude, and don't have to worry about the accuracy. This is different from your study of advanced algebra and fractions. Physics is broad and profound, comprehensive, flexible, and full of fun. Do you feel the fun of learning physics? "

Shen Qi found that all physics teachers seemed to like to snap their fingers, his high school physics teacher was like that, and his college physics teacher was still like that.

During the break between classes, Professor Ren approached Shen Qi alone for admonition: "I know that you have already obtained your bachelor's degree certificate, so you don't need to come to my big object class, but should you urge other students to attend class?"

"It's because of my ineffective supervision. For students in the mathematics department, physics is of great significance. I will let them attend classes and improve the attendance rate of the whole class." Shen Qi said.

"I heard that you won the CPhO gold medal in high school?" Ren Buqi asked.

Shen Qi nodded: "Yes, the teacher of my high school Wujing team graduated from the School of Physics of Yanda University with a Ph.D. in Astrophysics."

"Oh, what's it called?"

"Teacher Mu Rongmu."

"It turned out to be Xiao Mu, my student." Ren Buqi said calmly, with the demeanor of a famous teacher emerging spontaneously.

Shen Qi trembled, I am Teacher Mu's student, and Teacher Mu is Professor Ren's student, so according to the ranking, Professor Ren is my ancestor!