When it comes to the Qiantang River, everyone is familiar with it, it is located in Zhejiang Province on the mainland, and the Qiantang tide is famous all over the world, and many tourists come to watch it every year. There are even more poems: "Qiantang looks at the waves, and the tide is in front of you in an instant." It seems that in the ordinary river water, the energy can be shocking. It can be seen how magnificent the tide of the Qiantang River is, and the momentum is amazing.
How is the tide of the Qiantang River formed, and is it the same principle as the rising tide of the sea?
01, gravitational force is not equal to tidal force
Seeing that someone used gravity to calculate the gravitational effect of the sun and the moon on gravity, and came up with the moon's effect on the earth is only 1/270, I thought about it carefully, and it seems that this way of calculating is unreasonable.
Because, gravitational force is not equal to tidal force. When it comes to tides, there should be another thing, called the tidal force, which requires a separate calculation: the tidal force acting on a celestial body is directly proportional to the diameter of the celestial body and inversely proportional to the cube of the distance at which the gravitational pull is generated by another object.
The tidal force acting on an astronomical body, such as the Earth, is directly proportional to the diameter of that astronomical body and inversely proportional to the cube of the distance from another body producing a gravitational attraction, such as the Moon or the Sun.
Therefore, when calculating, you need to choose a cube instead of a square. In this calculation, it is just the other way around, the tidal force caused by the sun is really not as good as that of the moon, and the tidal force of the moon is about 2.2 times that of the sun.
02, how the tides are formed
The formation of tides is mainly due to the gravitational pull of the sun and moon. Many times, we think that the tide seems to be the wave, so we think that the tide is caused by the wind, but in fact, people who live by the sea must be familiar with the fact that no matter how big or small the wind is, the sea water rises and falls regularly, which shows that the tide has other influences. And this influence is the celestial body.
I believe that when we study physics, we all understand the formula for calculating gravity, but it is difficult for us to feel the difference in gravitational force brought to us by celestial bodies, for example, between day and night, we do not feel the obvious change in gravitational force. But when this scale is magnified to an astronomical scale, then the gravitational effect is obvious. The two major planets, the Sun and the Moon, have a huge gravitational pull on our Earth, and this gravitational pull acts on the ground, which is the tidal phenomenon of the oceans.
Of course, this tidal phenomenon is already very large, if it is bigger, you have seen "Interstellar", the tidal force in it is so big that it can directly destroy everything.
03, Why is the tide of the Qiantang River so spectacular?
If the above is to say that the existence of tides is universal, then why is the tide of the Qiantang River so good? The answer is that the time and place are favorable.
First of all, the time of the tide, the time of the tide of the Qiantang River is basically the same every year, why? Because at this point in time, the sun, the earth and the moon are roughly on the same line, so it will bring great tidal force, and the tide caused by it is naturally large.
Secondly, the geographical advantage, the unique topography of the Qiantang River, which exacerbates the expressiveness of this tide
When a large amount of water gushes in, the shrinking structure of the Qiantang River is called a trumpet, and the amount of water remains the same, as the river continues to narrow, it forms a more and more ferocious tide of the Qiantang River.
According to the previous forecast, we can also see that during this period, the ups and downs of the tide of the Qiantang River are indeed the most violent