Chapter 9: , How to calculate Earth mass

"It's all a group of people who are not doing their jobs properly, but they have nothing to say."
Qin Yi shook his head helplessly and began to look for books.
Huaxia University's library collection is very rich, and in the whole of Huaxia, it is estimated that it can surpass the collection of Huaxia University's collection is only the Imperial University.
The entire huge library has everything from the most basic books to books in the professional field, and all the books are numbered. In the internal library network, you can accurately find the location of the books, 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 books on mathematics, physics, chemistry, biology, and even literature, art, music, etc., very complicated. In other words, you should read books in order to avoid being tired and easier to absorb.
"Encyclopedia of Mathematics in High School ~"
Qin Yi picked up a book and began to look seriously. Although it is said to start from the basics, Qin Yi can not always learn the content of elementary and junior high school, at least naturally from high school.
High school mathematics, Qin Yi learns very well, the college entrance examination is almost full marks, so when learning this high school mathematics knowledge, it is very easy, there is no trace of difficulty.
"My memory has improved a lot, and I can almost remember it."
Quickly, Qin Yi discovered a huge change in himself. Although he had been in high school for three years, he did n’t know how much he had done, and he remembered many things very firmly.
But after all, I am also a junior now, I have n’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 contents of the book clearly, never forget, and combine The experience of studying in high school before quickly made things clear.
看来 "It seems that the old man really did not brag. This genetic optimization solution is really amazing. It can really develop the brain, and my physical fitness has increased a lot."
Qin Yi, while reading a book, lamented the magic of the gene optimization solution.
"Bragging, I need to brag ~"
In the mind, inside the technology tower, the old man couldn't help blowing his beard and staring.
In less than 10 minutes, I read a thick book of high school mathematics knowledge.
"Learning the old and learning the new, what the ancients said is still very reasonable. If you study the mathematics knowledge of high school again from the beginning, you will have a deeper understanding of mathematics."
"Many people think that mathematics is useless, but in fact mathematics is the real foundation for modern scientists. Without breakthroughs in the field of 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 exam-oriented education, but in the mental thinking of the future. Learning mathematics is a simple to complex thinking exercise process. Many people think that learning mathematical knowledge is useless in the future. Indeed, if they are not in the future, It doesn't take much mathematical knowledge to do related academic work. "
"But on the other hand, people with good mathematics often have clear thinking, logical coherence, and subjective initiative. They are better at solving problems. Many people use clumsy solutions to solve problems. And it will have a variety of reverse thinking, transformative thinking, and it will be very useful as the accumulation grows. "
Qin Yi closed her eyes and kept recollecting her knowledge of high school mathematics in her mind. Think again about many of her classmates in high school. People with good math scores often think of good science scores, because science needs to use their brains to think constantly. It's easy to understand and difficult to understand.
People with poor math scores often choose to study liberal arts. Many things like liberal arts are memorized and moved hard, which is quite different from the activity of science.
"It seems that I still have to learn more mathematics in the future and exercise more of my thinking ability. At first, I felt that learning high numbers in mathematics has basically deviated from the actual needs. Now it seems that my understanding is still too superficial. "
Qin Yi gently put down the mathematics, picked up the detailed knowledge of high school physics, and continued to look at it. Qin Yi, a senior high school physics student, also learned quite well.
I revisited the physics knowledge of high school again. Qin Yi learned it very quickly, turning over a page in ten lines at a glance, and reading a thick detailed explanation of high school physics.
"Qin Yi, have you learned anything after watching it?"
In his mind, the old man chatted with Qin Yi a bit boring. After Qin Yi read the high school physics knowledge, the old man naturally knew the level of civilization development on the earth.
"The harvest is ok."
Qin Yi smiled and nodded.
"Let me test you, do you know how to calculate the quality of the earth?"
The old man smiled, his eyes turning.
"What's difficult, according to the law of gravity, 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 finally simplifies M = V ^ 2 R / G, V is the speed of the earth's rotation (you can find the speed by knowing the radius of the earth), you can calculate the mass of the earth by bringing in the data. "
Qin Yi doesn't care. The calculation of the planet's mass needs to use the law of gravity. As long as you know this, it is easy to calculate the mass of the earth.
"Don't read books for reading. You can remember these formulas, numbers, etc., but if you can use this tool to measure the quality of the earth, can you figure it out?"
In his mind, the old man did not seem to be satisfied with Qin Yi's answer, and said with a smile.
Then in Qin Yi's mind, a picture appeared. In the picture, a thin wire lifted an elongated magnetic needle from the middle, and two shots were placed not far from the two sides of the magnetic needle.
"This thing can measure the mass of the earth?"
Qin Yi looked at this thing, suddenly suddenly confused, something is unknown.
"Of course, this thing is still something invented by scientists on your earth to measure the mass of the earth. It's called a" twist scale ". In the 18th century, your scientist on the planet Cavendish relied on this thing to calculate Out of the mass of the earth. "
The old man nodded with certainty, and then began to talk about the origin and role of Twisting Scales.
The basic principle of a torsion scale is to connect two rigid weights of the same mass at a certain height to both ends of a rigid rod, and suspend it with a twisted wire through the center of the rod.
The weighing rod can rotate freely around the twisted wire. When the gravity field is not uniform, the gravity of the two masses is not parallel. A slight difference in this direction causes a small horizontal component of force on the two masses and generates a torque to rotate the suspension system around the twisted wire until it is balanced with the torque of the twisted wire.
In the 18th century, a problem that scientists on the earth have been worrying about is how to calculate the mass of the earth. Until 1798, Cavendish finally used the 'twist scale' to see that the mass of the earth was calculated, which is about 60. Trillion trillion 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 greater mass of the sun, which is 300,000 times the mass of the earth. It is 2 × 103o kg.
Then the masses of other planets in the solar system were also measured one after another. The seemingly simple Twisting Scale was able to calculate the mass of a huge and cosmic celestial body. The fundamental principle is the law of gravity.
原来 "So, why didn't we learn these things in high school?"
After listening to the old man's stress, Qin Yi realized that everything was clear, and then frowned, thinking. With the current high school physics knowledge, it is not a problem to calculate the mass of the earth by himself. It is necessary to know that in the 18th century, scientists could already think Find ways to calculate the mass of the earth.
But I never thought about it, just memorizing it, and constantly calculating in the sea of ​​questions. Although I already know a lot of things, when I really want to calculate the mass of the earth, I am completely discredited. UU Kanshu www.uukanshu.com
"In my opinion, there are actually many problems with your current education in China. The most serious one is exam-oriented education. It only depends on the results of the exams. It doesn't care about other things."
或许 "Perhaps you are all very powerful on the exam, but when you really do scientific research and exploration, you still have to develop more of your own ability to think and do."
只有 "Only in this way can you really produce great scientists, not just nerds who only do the subject."
The old man groaned for a long time. It has been connected to the entire earth's network for a long time, so it is very clear that the education situation in various countries and regions around the world. For the education model of Huaxia, it also quickly found many problems.
Today, just relying on Qin Yi, many problems were immediately exposed. As a student of a top academic institution such as Huaxia University, I will not mention the practical ability first. This ability of independent thinking and exploration alone makes it very Disappointed.
"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 opinions to refute the other party, he combined with everything he had experienced and was speechless.
When I was in high school, I was very nervous. If I did n’t take the exam, the teacher would simply choose not to speak. If I did n’t take the exam, such as music class or physical education class, other teachers would habitually occupy it. Lessons and so on, all this is enough to show that the education now is exam-oriented education.
I can't say that this kind of education has no benefits and advantages, but the disadvantages it brings also need to be looked at directly. Many things can't be avoided at all, and the impact is very far-reaching.
PS: Once the contract is signed, everyone can support a wave ~~~