my golden fishing village

Chapter 150 The Magical Tides

"Is the tide high?" Zhao Hao was taken aback.

"No way?" Han Hanhua looked at him with wide eyes, and asked incredulously, "You don't even know the ebb and flow of the tide, do you?"

"Really?"

Li Fangfang and the others all looked over.

"Who, who said it!" Zhao Hao said immediately after hearing the words: "Isn't it just the ebb and flow of the tide? Have I never eaten pork or seen a pig running? This is the first time I saw it with my own eyes."

"But the tide is high, is it dangerous?"

"Aren't you talking nonsense?"

Han Hanhua said speechlessly: "The tide is rising, do you think it is dangerous?"

"So what's going on with the high tide?"

"This…"

Han Hanhua was stunned for a while.

Zhao Hao's question really stumped him, yes, what is going on with this high tide?
"It seems to be related to the moon, right?" Ji Yun thought for a moment and asked.

"Let's get out of here first."

Chen Fan didn't rush to explain, and said: "When the tide rises, people will fall easily, and if they are not careful, they will be dragged into the sea water, and they have nowhere to use their strength to stand up."

"Row."

Several people walked towards the village.

While walking, Chen Fan explained, "Aren't you curious about tides? Now I will explain it to you, and the principle is not difficult to understand."

"Ji Yun, you just said that the rising and falling tides have something to do with the moon?"

"Well, isn't it?" Ji Yun narrowed his eyes.

She clearly remembered seeing it in the textbook.

"Hehe, that's right, but without the sun, to be precise, the tides are related to the sun and the moon."

"It has something to do with the sun and the moon?"

"gravity?"

Qian Ning said suddenly.

"Yes."

Chen Fan smiled and nodded, "Tide is the periodic movement of sea water under the gravitational force of the sun and the moon. People call the vertical fluctuation of the sea surface a tide, and the horizontal flow of sea water is called a tide. Our ancestors In order to indicate the moment of tide, the high tide that occurs in the morning is called tide, and the high tide that occurs in the evening is called tide, which is the origin of the name of tide.”

"The ones during the day are called tides, and the ones at night are called tides. Together they are called tides. So that's what happened." Zhao Hao suddenly realized.

"Then what is the principle?"

Qian Ning did not forget to ask, "Let's just say it is the influence of the sun and the moon, but how exactly is it affected?"

"Here, you have to listen carefully."

Chen Fan glanced at him and continued: "At the beginning, people did not realize that tides are the result of the dual effects of the moon and the sun, because it is impossible to explain only the gravitational effect of the moon. Tidal phenomena will occur at the same time. In the two areas of the earth's sea surface closest to the moon and the sea surface farthest from the moon, the spherical sea surface becomes a spindle, and the same is true for the sun."

"What do you mean? I don't quite understand..." Zhao Hao said awkwardly.

"... "

Li Fangfang hesitated to speak.

"That is to say, the distance between the side of the earth facing the moon and the side facing away from the moon is different. According to the calculation of the gravitational force formula, the gravitational force received is also different. Time should be different."

"Qian Xueba is still very good." Ji Yun praised.

"Beauty Ji, please stop making fun of me. This is the real top student." Qian Ning didn't know whether to laugh or cry.

Chen Fan smiled, and continued: "Later, scientists came up with another theory, which is now generally accepted. If the earth and the moon are regarded as particles, and the moon moves in a circle around the earth, it is actually not the case, because the moon also moves in circles. The ones that have mass are the moon and the earth, and they move in a circle around their common center of mass, but the earth's circular orbit is much smaller."

"Is it because the mass of the moon is smaller than that of the earth?" Han Hanhua asked.

"It's much smaller."

Chen Fan nodded: "If there are two planets with similar masses, then their circular orbits are approximately equal."

"I see."

"With the center of the earth as a non-inertial reference, the earth's particles are subject to the universal gravitational force of the moon's particles, which is the centripetal force of the earth's particles moving in a circle around the common center of mass. The inertial force corresponding to this centripetal force is equal to and opposite to this centripetal force, so the earth's particles are subject to The gravitational force of the moon particle and this inertial force cancel each other out.

Since the earth is regarded as a particle, the motion trajectories and dynamic laws of objects on the earth can be regarded as exactly the same as those of the earth. In this way, the gravitational pull of the moon and the corresponding inertial force of the object cancel each other out.
But in fact, the volume of the earth is very large. The orbital radius of the object on the ground nearest to the moon and the common center of mass of the earth and the moon is obviously smaller than the orbital radius of the earth’s particle, and the gravitational force of the moon on the object will be greater than that. Under the corresponding inertial force, these two forces can no longer cancel out, and the resultant force is opposite to the direction of the universal gravitational force of the object, which makes the gravity of the object significantly smaller.

If the "object" in question is the ocean water here, then there is a high tide happening here.

Using the same method to study the objects on the ground farthest from the moon, the gravitational force of the moon on the objects here is smaller than the corresponding inertial force, and their resultant force is opposite to the direction of the gravitational force of the earth on the objects here, which also makes the objects Gravity is significantly smaller, so there will also be high tides in the part of the sea farthest from the moon at the same time, which makes the sea level that should be spherical slightly present a spindle shape. "

Zhao Hao and others could understand it at first, but the following words about centripetal force and inertial force were confused.

On the contrary, it was Ji Yun and Qian Ning who could listen to the spirit.

Qian Ning's eyes lit up, and said, "The sun is the same for the earth?"

"Yes, the study of the sun's effect on the tides is the same as the study of the moon's effect, so I won't go into details.

Ground tides, sea tides and air tides are all caused by the above reasons, and the three influence each other.

However, because the moon is closer to the earth than the sun, the ratio of the tidal forces of the moon and the sun is 11:5. For the ocean, the lunar tide is more significant than the solar tide.The elasticity and plasticity of the crust at the bottom of the ocean lead to tidal deformation, which will cause corresponding ocean tides, that is, for ocean tides, there is a ground tide effect; and the migration of seawater quality caused by ocean tides changes the load on the crust, making the crust Repeatable changes occur.The air tide is above the ocean tide, and it acts on the sea surface to cause additional vibrations, making the changes in the ocean tide more complicated.

This energy passes through the friction between the shallow sea area and the coastal area. At the new moon, the sun and the moon are on the side of the earth, so there is the greatest tidal force, so it will cause a "big tide". Near six, the sun and the moon are on both sides of the earth, and the tidal force of the sun and the moon will also cause "spring tide" if you push and pull;
When the moon phase is the first and last quarters, that is, the eighth day and the 23rd day of the lunar calendar, the tidal force of the sun and the moon cancel each other out partly, so a "neap tide" occurs. Everywhere you see the beach". "

(End of this chapter)