Daming: If I find a great-grandson, I will teach an emperor through the ages

Chapter 1 Can you fly to the sky?
Hongwu 25 years.

In a small courtyard on the outskirts of Yingtian Mansion.

"Father, be careful."

A handsome young man wearing coarse clothes looked worriedly at Cao Wei, who was climbing up to the roof.

It was mid-August at this time, and the weather was unbearably hot. Everywhere I looked, there were heat waves churning and glaring reflections of the sun.

Naturally, Cao Wei climbed up the roof in the bright sun not because of any masochistic tendencies, but because he wanted to prove something to his son...

After he climbed onto the roof, he carefully stepped on the sloping tiles on the roof to the edge of the eaves, and took out two stones, one large and one small, from his bulging arms.

"How about it? I'll give you one last chance now. Do you still think the big one will hit the ground first?"

Cao Wei stretched out his arms and shouted downwards.

Cao Ying shook his head. Although there was worry about his father standing in a high place in his eyes, he still insisted on his idea.

How could the big stone and the small stone fall to the ground at the same time?

Isn't the big stone much heavier than the small stone?
If both would hit the ground at the same time, wouldn't the extra weight of the big stone over the small one be meaningless?
"Father, the big rock must have hit the ground first. The two rocks are not the same weight, so how could they hit the ground at the same time?"

Cao Wei looked at the innocent Cao Ying below and grinned: "That person needs to see clearly."

As he spoke, he shook the two stones of different sizes in his hand.

"three."

"two."

"one!"

Cao Wei suddenly opened his hands, and the two stones fell down quickly.

Cao Ying's eyes, which were slightly squinted because of the glare of the sun, suddenly widened, staring at and following the two falling stones without blinking.

quickly,

With a "plop", two stones fell to the ground.

Cao Ying looked at the incredible scene in front of her and was speechless.

He could see clearly that two stones really fell to the ground at the same time!

Why is that?
Aren't big rocks heavier than smaller ones?
Or is there something special about the two stones in father's hand?They look different in size, but they are actually the same weight?

He raised his head and looked at his father who was smiling at him from the rooftop, his eyes full of doubts.

"Did you see clearly?"

"See clearly, they are... two landing at the same time."

Cao Wei nodded, and then carefully climbed down the ladder from the roof.

Cao Wei is not a weakling. The reason why he looks so clumsy and laborious going up and down the roof is because he is afraid of heights.

His house is not tall, but for Cao Wei who is afraid of heights, it is really terrible.

Until his feet touched the ground again, a sense of security instantly enveloped him, his waist was no longer sore, and his legs were no longer weak.

Cao Ying could no longer suppress her curiosity. She went over to pick up the two stones and weighed them in her hands, only to find that they were two of the most common stones. They could be seen everywhere on the roadside, and their weights were also very different.

Now, he was even more confused, and there were a hundred thousand reasons in his heart.

Seeing Cao Wei coming over, Cao Ying couldn't wait to ask: "Father, this...why is this? They are obviously not the same weight, why do they fall to the ground at the same time?"

Cao Wei showed an inscrutable smile, "Because the gravitational acceleration exerted on them by gravity is the same."

"Gravity?" It was obviously the first time Cao Ying heard this name, and there was only confusion in his eyes. “What is gravity?”

Cao Wei dragged him to the cool shade under the eaves, took two stones from his hand and threw them out.

"Jump."

"what?"

"I told you to jump."

Cao Ying nodded silently, then jumped up.

"Jump again."

Cao Ying:? ?

There was no other way, Cao Ying could only use her legs to jump up again, this time higher than the last time.

"Jump again, use your strength!"

Cao Ying exerted all her strength and jumped hard.

This time it was his limit, and he jumped even higher than the previous time.

"Look, no matter how high you jump, you will eventually fall. Why do you fall instead of flying directly?"

Cao Wei was very relaxed and casual, saying words that Cao Ying couldn't understand and felt a little funny.

"Father, I don't have wings, how can I fly? Only birds can fly." Cao Ying felt that Cao Wei's question was too childish and couldn't help but answer with a smile.

Cao Wei smiled and nodded: "You're right, only birds can fly, but they will also fall to the ground or branches to rest when they are tired."

"But... have you ever wondered why the sun in the sky never sets? Whether it is the sun, the moon, or the stars, they hang in the sky for thousands of years and never set."

Cao Ying was stunned for a moment, the smile on his face quickly disappeared, and he frowned and began to think.

After a while, he raised his head and looked at Cao Wei: "Father, why is this?"

He didn't want to understand.

Seeing the strong desire for knowledge in Cao Ying's eyes, Cao Wei was very pleased, and then he spoke seriously:

"Everything in this world has a gravitational force that attracts each other. We call it universal gravity."

"Just like magnets, there is nothing between them, but there is an attractive force that can attract both sides, but if the two magnets are placed too far away, the gravitational force between them will become weak and they will not be able to attract each other."

"Gravity is also a type of gravity. What we feel is called gravity. It is a component of gravity. It is invisible and intangible, but it does exist and allows you to stand firmly on the ground."

"Gravity has an attractive effect on all objects, which means that you will not fly away when you jump, birds will get tired after flying for a long time, and stones will fall from high places."

"And this attraction has the same effect on the acceleration of each object, so two stones of different sizes will fall to the ground at the same time."

Cao Wei pointed to the top of his head and continued: "There is also gravitational attraction between the sun, moon, stars in the sky, and the earth. However, they rotate and fly too fast in the universe, and the centrifugal force generated overcomes the gravity. At this time Gravity is like a rope pulling them tightly, and if gravity disappears, centrifugal force makes them fly away."

"You jumped up just now because you generated centrifugal force, but when the centrifugal force was exhausted, gravity pulled you back."

At this moment, Cao Ying's bright eyes were full of shock!
In his eyes, the whole world now seems to be different from what it used to be. For the first time, he looks at this world with a thinking eye.

In the 18 years since he was a child, he learned for the first time that there is such a thing as gravity in the world!

It's invisible, intangible...but it's definitely there.

He won't fly away when he jumps, birds will get tired after flying for a long time, and stones will fall. This is all because of gravity...

The sun and moon do not set because they have centrifugal force, which overcomes gravity...

Gravity exerts the same force on all objects…

Cao Ying lowered his head to look at the ground, then raised his head to look at the sky. The scorching sunlight made him squint his eyes slightly.

Then, another question came to his mind, he turned his head to look at Cao Wei, his eyes were full of excitement:

"Father, tell me, if a person is strong enough, jumps high enough, and has enough centrifugal force, can he fly to the height of the sun and the moon?"

Cao Ying's inference made Cao Wei very much recognize that his son was smart since he was a child.

He nodded and said, "Yes, enough centrifugal force can overcome the gravitational constraints of the earth's center, but no matter what, a person can't jump that high."

"Oh." Cao Ying's eyes dimmed slightly.

However, Cao Wei's next words made his eyes shine brightly again.

"But I have a way to send people to heaven."

"Really?!" Cao Ying was extremely excited again.

Can people really overcome gravity and fly to the sky?

"Father, how can we..."

In the middle of his words, Cao Wei stopped him with his hand.

"I'll talk to you again when you come back."

Cao Ying nodded heavily, his eyes burning, as if there was a warm little sun in his eyes.

Cao Wei smiled, entered the room and began to pack things for Cao Ying.

After a while, Cao Ying picked up a small package, opened the courtyard door, turned around and saluted Cao Wei.

"Father, the child has gone."

"Go ahead and wait for your good news." Cao Wei waved to him.

Afterwards, Cao Ying walked further and further away under Cao Wei's gaze.

(End of this chapter)