Since Wu Linfeng and Tang Ao had a "duel" for Song Huiqin, Song Huiqin didn't want to get entangled in these "boring" things, so he drew a line with them. She should devote herself to her own studies and not delay her studies for the sake of these children's personal affairs. In her opinion, her life and destiny are in her own hands, and she does not need to rely on others, do not need to bother others, and does not need to be disturbed by others.

Since studying "Introduction to Mao-Zedong Thought", Song Huiqin has already understood the "class" she is in, and she can only rely on her own efforts to cross this "class" without the charity of others. She set high ideals for herself, and she wants to realize them slowly. However, ideals can't be eaten, for the sake of the current life, and in order to reduce the burden on her parents, Song Huiqin found a tutor. The employer is a building materials store owner, also surnamed Song, known as Boss Song, who is busy with business all day and is unable to take care of his children's studies. The child was in his first year of high school and his physics grades were not good, so Song Huiqin specially tutored him in physics. At that time, the real estate market was hot, the building materials business was booming, and Boss Song made a lot of money. Boss Song said that as long as Song Huiqin gets the child's grades, in addition to the normal remuneration, he will also give her a bonus.

Going to class, studying, and being a tutor, the days passed like this, and Song Huiqin lived a very fulfilling life. Being a tutor did not affect her learning, on the contrary, some of the questions raised by the students in the learning process induced her to think deeply. She found that she hadn't asked a university professor a question for a long time during her studies, and they all crammed for whatever the professor said. Over time, their critical spirit of scientific research slowly disappeared.

In the blink of an eye, in June, Song Huiqin took the CET-4 test for college English. Hu Kehao mobilized the entire applied physics students, and the registration rate of English level 4 reached 90%, and those who hoped to pass were registered, and those whose academic performance was too poor came again next time, anyway, there were two opportunities for the exam a year. For Song Huiqin, although she is a battle-hardened exam master, after the exam, she is also uneasy in the process of waiting for the results. She is a member of the study committee of the class and a role model for the whole class, if she has not passed the exam, she will not be able to pass the face, how will the classmates look at her with colored glasses?

Every weekend, the traffic outside the gate of U City Polytechnic University is bustling and lively. There are students who go out to dinner, there are other schools who come to meet friends of the opposite sex, and there are parents who come to pick up their children. Song Huiqin had dinner early, returned to the dormitory to pack her bag, and wanted to be a tutor. Chen Qiuhe also dressed up in the bedroom, wearing eye shadow, eyeliner, eyelashes, eyebrows, lipstick, and perfume. Song Huiqin knew that Chen Qiuhe had a date every weekend and dressed herself up as a goblin. There are two bags on the table in the bedroom, one is a bag of about 100 yuan carried by Song Huiqin, and the other is a high-end LV bag carried by Chen Qiuhe. Song Huiqin's bag is "millet plus rifle", and Chen Qiuhe's bag is "plane plus tank", and they are facing each other there. Song Huiqin and Chen Qiuhe have different consumption concepts, and they can't talk about it together, so Song Huiqin didn't pay attention to her.

Song Huiqin came out of the dormitory, came to the school gate, got on the bus, changed the bus again, and came to the house of Boss Song, the employer of the Cuihu Harbor Community. Cuihu Harbor is an upscale community with swimming pools, fountains, basketball courts, garden landscapes, pavilions, and amusement facilities, and is a wealthy area where high-end white-collar workers, bosses, and nouveau riche all live.

Boss Song's son Song Xiaotao learned to love to break the casserole and asked in the end, I don't know if this is an advantage or a disadvantage. Many times, the teacher can't answer the questions he asks. The teacher said that you just need to know what it is now, and as for the "why", we will talk about it later. Scientists can't understand the deep-seated problems, and now they only need to be able to do them.

Song Huiqin tutored Song Xiaotao to learn the law of gravitation in physics - that is, any two objects in nature are attracted to each other, and the magnitude of gravity is proportional to the product of the masses of the two objects, and inversely proportional to the square of the distance between the two objects.

"Teacher, I can memorize the law of gravitation, and I can calculate the data given to me. But I don't understand the essence of this law. Song Xiaotao said.

"What don't you understand?" Song Huiqin asked.

"Why is there a 'gravitational force' and not a 'universal repulsion' between objects? Why can it only be attracted, not repelled? Song Xiaotao asked.

"This was discovered by scientist Isaac Newton by observing an apple falling to the ground, and it has been verified in astronomy. You see it as a proven truth. ”

"I've read some popular science articles that say that the universe is expanding at an accelerated rate. If there is gravitational attraction between planets, then the direction of gravity is opposite to the direction of the expansion of the universe, according to Newton's second law, the expansion of the universe should be slower and slower, why do scientists observe that the universe is expanding faster and faster? Song Xiaotao asked.

"There may also be a force acting in the opposite direction, opposite to the direction of gravity, which acts as a repulsion, so the universe is expanding faster and faster." Song Huiqin said.

"Is this force a universal repulsion?"

"Scientists don't call it universal repulsion, but it works against gravity. Scientists call it 'dark energy,'" Ms. Song said.

"It's called 'dark energy' because it's dark and hasn't been discovered yet?"

"Yes, these things don't emit light, they don't interact with electromagnetic forces, and with current technology, people can't observe them, they are like ghosts in the universe. When you become a scientist, you can study these problems, so now you need to raise your grades. Song Huiqin said.

"How do I become a scientist?"

"I've heard them say that when you have a lot of national-level projects, a lot of awards, a lot of SCI articles, a lot of funding, a lot of titles, and preferably academicians, you become a scientist." Song Huiqin said.

"What if you don't have those?"

"Without these, at most he is a citizen scientist, and his research results are not recognized by the academic community."

According to the data in the title of the study guide, Song Xiaotao either calculates the gravitational force between the planets, the mass of the planets, or the distance between the planets, and the calculation method is not complicated.

"Why are there so many gravitational constants?" Song Xiaotao asked again.

"This is data that scientists have measured with precise experiments." Song Huiqin said.

"What would happen to the world if the gravitational constant was a little bigger, or a little smaller?"

"I don't know. Maybe the world won't be stable, and you won't be able to ask questions here. Song Huiqin said.

"Could it be that this data was designed by a supreme 'god'?"

"I don't know. Newton probably didn't know it either, and it is said that he spent his later years studying 'God'. Don't think about it so much, you just need to be able to do the questions now," Song Huiqin said.