Interstellar Industrial Age

Chapter 9, How to Calculate the Mass of the Earth

"It's all a group of people who don't do their jobs properly, but they are so arrogant that they have nothing to say."

Qin Yi shook his head helplessly and started looking for books.

The library of Huaxia University has a very rich collection of books. In the whole of China, it is estimated that only the Imperial Capital University can surpass the collection of Huaxia University.

The entire huge library has everything from the most basic books to the books in the professional field, and all the books are numbered. The location of the books can be accurately found in the internal library network, which is very convenient to find.

After more than ten minutes, Qin Yi returned to his seat with a pile of books. There were more than ten books, including mathematics, physics, chemistry, biology, and even literature, art, music, etc. It was very miscellaneous. In other words, reading should be changed to read, so that it will not be tired and it will be easier to absorb.

"Encyclopedia of high school mathematics knowledge~"

Qin Yi picked up a book and began to look seriously. Although he said that he started learning from basic things, Qin Yi couldn't learn the content of elementary school and junior high school. At least naturally, he started to learn from high school.

In high school mathematics, Qin Yi learned very well, and he almost got a full score in the college entrance examination, so when he learned this complete high school mathematics knowledge, it was also very easy, without a trace of difficulty.

"My memory has improved a lot, and I can almost never forget it."

Soon, Qin Yi discovered a huge change in himself. Although he had studied mathematics in high school for three years, he didn't know how many questions he had done, and he remembered many things very firmly.

But after all, I am also a junior now, and I haven't learned these things for a few years, but I read the book very fast, almost ten lines at a glance, but I remember the content of the book clearly, never forget it, and then combine it The experience of studying in high school in the past quickly made things clear.

"It seems that the old man really didn't brag. This genetic optimization solution is really amazing. It can really develop the brain, and my physical fitness has increased a lot."

Qin Yi sighed at the magic of genetic optimization fluid while reading the book.

"Bragging, I have to brag~"

In his mind, inside the technology tower, the old man couldn't help blowing his beard and staring.

In less than 10 minutes, a thick book of high school mathematics knowledge was read.

"Reviewing the old and learning the new, what the ancients said is still very reasonable. If you learn the mathematics knowledge in high school from scratch, your understanding of mathematics is much deeper."

"Many people think that mathematics is useless, but in fact mathematics is the real foundation of modern scientists. Without breakthroughs in mathematics, there is no way for scientists to achieve in-depth development in other fields."

"The real effect of mathematics is not reflected in the test-oriented education, but in the future mental thinking. Learning mathematics is a process of thinking exercise from simple to complex. Many people think that mathematics knowledge will be useless in the future. It is true that if you are not in the future. Basically, you don't need much mathematics to do related academic work."

"On the other hand, people who are good at mathematics tend to have clear thinking, coherent logic, and better subjective initiative in dealing with many things. Many people solve problems with stupid methods, they can often use their own thinking to hit the nail on the head. And it is very useful to have all kinds of reverse thinking and transformational thinking as the accumulation grows.”

Qin Yi closed his eyes and kept recalling the knowledge of high school mathematics in his mind. He also thought about many of his classmates in high school. People with good mathematics scores often think that they have good grades in science, because science requires continuous thinking. It's easy to understand, hard to understand.

People with poor math scores often choose to study liberal arts. Many things like liberal arts are rote memorization, which is very different from the activity of science.

"It seems that I still need to study more mathematics in the future.

I need to exercise my thinking ability more. At first, I felt that learning advanced mathematics in mathematics is basically out of the realistic needs. Now it seems that my understanding is still too superficial. "

Qin Yi put down the math gently, picked up the detailed explanation of high school physics knowledge, and continued to read it. Qin Yi also studied physics in high school quite well, and he also got a very high score in the college entrance examination that year.

Revisiting the physics knowledge in high school again, Qin Yi learned it very quickly, turning a page in ten lines at a glance, and reading a thick detailed explanation of high school physics knowledge.

"Qin Yi, did you gain anything after reading it?"

In his mind, the old man was a little bored to chat with Qin Yi. After Qin Yi read the physics knowledge in high school, the old man naturally knew very well the level of civilization development on this side of the earth.

"The harvest is okay."

Qin Yi smiled and nodded.

"Then I will test you. Do you know how to calculate the mass of the earth?"

The old man smiled and said, turning his eyes.

"What's so difficult about this, according to the law of universal gravitation, F=GMm/R^2, where G=6.67*10^(-11), M is the mass of the earth, m is the mass of an object, and R is the radius of the earth. F= m*V^2 /R is finally simplified to M = V^2*R/G , V is the speed of the earth's rotation (the speed can be obtained by knowing the radius of the earth), and the mass of the earth can be calculated by bringing the data in. "

Qin Yi didn't take it seriously. The calculation of the planet's mass needs to apply the law of universal gravitation. As long as you know this, you can easily calculate the mass of the earth, which is not difficult for Qin Yi at all.

"Don't study hard, you remember these formulas, numbers and the like, but if you use this tool to measure the mass of the earth, can you calculate it?"

In his mind, the old man didn't seem satisfied with Qin Yi's answer, he said with a smile.

Then, in Qin Yi's mind, a picture appeared. In the picture, a thin wire hoisted a slender magnetic needle from the middle, and two lead balls were placed on both sides of the magnetic needle not far from each other.

"Can this thing measure the mass of the earth?"

When Qin Yi saw this thing, he was at a loss, and he didn't know why.

"Of course, this thing is still invented by your scientists on earth to measure the mass of the earth. It is called a 'torsion balance'. In the 18th century, your scientists on earth, Cavendish, relied on this thing to calculate out of the mass of the Earth."

The old man nodded affirmatively, and then began to talk about the origin and function of the 'torsion balance'.

The basic principle of a torsion balance is to connect two weights of the same mass at a certain height at both ends of a rigid rod, and hang them with a torsion wire through the center of the rod.

The scale rod can rotate freely around the torsion wire. When the gravitational field is not uniform, the gravitational force on the two masses is not parallel. This slight difference in direction induces a small horizontal component of force on the two masses and creates a moment that rotates the suspension system around the torsion wire until it is balanced with the torque of the torsion wire.

In the 18th century, one of the problems that scientists on earth have been worrying about is how to calculate the mass of the earth. Until 1798, Cavendish used the 'torsion balance' to finally calculate the mass of the earth, which is about 60 trillions of tons.

Because the measurement calculated the mass of the earth, scientists soon calculated the density of the earth. Soon, scientists used the same method to measure the even greater mass of the sun, which is 300,000 times the mass of the earth. For 2 × 103o kg.

Then the masses of other planets in the solar system were also measured one after another. The seemingly simple 'torsion balance' was able to calculate the mass of the enormous cosmic celestial bodies. The fundamental principle is the law of universal gravitation.

"I see, but why didn't we learn these things in high school?"

After listening to the old man's instructions, Qin Yi became enlightened. Then he frowned and pondered. Among them, with the physics knowledge in high school, it is not a problem to calculate the mass of the earth by himself. You must know that in the 18th century, scientists were already able to think about it. Come up with a way to calculate the mass of the earth.

But I never thought about this issue, I just memorized it by rote, and kept calculating in the sea of ​​questions. Although I already knew a lot of things, when I really wanted to calculate the mass of the earth, I was discredited.

"In my opinion, there are actually quite a few problems with your current education in Huaxia. One of the most serious ones is exam-oriented education, which only depends on the results of the exams. As for other things, you don't care at all."

"Maybe in the exam, you are all very good, but when you really come to scientific research and exploration, you still need to cultivate your ability to do and think more."

"That's the only way to really produce great scientists, not nerds who can only do problems."

The old man pondered for a long time. It has long been connected to the entire earth's network, so it is very clear about the education situation in various countries and regions around the world. Regarding the education model on China's side, it also quickly discovered many problems.

Today, just relying on Qin Yi, immediately exposed a lot of problems. As a student of a top institution like Huaxia University, I will not talk about the practical ability. The ability of independent thinking and exploration alone makes it very disappointment.

"It's true~"

After listening to the old man's words, Qin Yi thought for a long time and had to nod his head to admit it. Although he could find a lot of points to refute the other party, he was speechless based on everything he had experienced.

When I was in high school, I was very nervous about studying. If I encountered something that was not tested, the teacher would simply choose not to teach it. When I encountered a class that did not require testing, such as music class, physical education class, etc., other teachers would habitually come to occupy it. Classes, etc., all this is enough to show that the current education is exam-oriented education.

It cannot be said that this kind of education does not have any benefits and advantages, but the drawbacks it brings must also be looked at directly. Many things cannot be avoided at all, and the impact it brings is also very far-reaching.

PS: After signing the contract, everyone can strongly support a wave~~~

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