Comment on the advantages and disadvantages of rain

The rain in the poet's eyes is poetic, however, the rain in nature is endless. It can wash away bridges, flood and destroy crops, and bring disaster to mankind. Next, please talk about the different situations of rain from a scientific point of view.

1. Tell an example of rain flooding.

In ancient times, Dayu controlled water and Bangladesh was flooded.

2. List the strange phenomena related to rain: plum rain, Yu Qian, mud rain, acid rain and so on. Talk about the causes of their formation and the disasters they bring to mankind.

(1) Meiyu:

From the middle and late June to the early summer of the first half of July, the narrow area from the middle and lower reaches of the Yangtze River (or Jianghuai Basin) to southern Japan often has a continuous rainy period, with frequent precipitation processes and frequent heavy rains. At this time, it is the mature period of plums in Jiangnan, so it is called "Meiyu". The ancient poem "It rains at home in Huangmei season, and frogs are everywhere in the grass pond" vividly depicts the natural scene of the local rainy season. Because of the high humidity and temperature in the rainy season, clothes are easy to get moldy, so it is also called "mildew rain".

(2) Yu Qian:

(1) phenomenon:

Speaking of Yu Qian. According to the materials published in People's Daily, "One day in 1994, there was a sudden shower with a large number of ancient copper coins in Gorky State of the Soviet Union, which was called the copper coin rain". In China, there are many such examples. According to Ren Fang in the Southern and Northern Dynasties, in his book Strange Tales, "During the week, it rained all day in Xianyang." "When Wang Mang was young, it rained five baht in Weiyang Palace."

"In the Han Dynasty, the family expenses of Yingchuan people were very high." According to the Records of the Song Dynasty and the Five Elements, "In July of the second year of Shaoxing, money rained or stones flowed out." There is also such a record in the Collection of Ming History: "Chenghua made friends on June 9, when it rained heavily in the capital, he often made money in the rain." Yu Qian is not a miracle.

Besides, we also know that there is golden rain. "Bamboo Chronology" contains: "Yu Xia eight years in summer and June, Xiayi rain gold." Later, Ren Fang wrote: "Confucianism said: It rained for three days in the era of Xiaxia. There is a saying in ancient poetry: "You can get peace and rain, and make it as low as earth. "... yes. "He wrote in Shuo Wen Jie Zi:" When Zhou Chengwang was in office, Xianyang paid gold. There is rain and gold in Xianyang today. " "In the second year of Emperor Hui of Han Dynasty, there was gold and black tin in the palace." "In the Han Dynasty, Weng Zhong's Confucianism was a masterpiece of poverty, and he lived in Weichuan. When it rains, his home is ten times. " I wonder if there is such a golden rain abroad?

And Grain Rain. Ren Fang said: "When King Huan of Wu was in power, Jinling gave food to the poor, and the rich did not rain." According to him, it seems that God can distinguish between the rich and the poor. Of course, this is an incidental meeting. Liu's Other Gardens in Song Dynasty

It also reads: "Zhang Jun, a native of Liangzhou, whose name is Gong Yan, spent nine years in Wuwei, stewed and planted." There is a drop of rice in the grain. For example, Cui Bao in the Jin Dynasty wrote in Notes on Ancient and Modern Times: "In the third year of Huidi, rice and rain fell in Guigong and Yangzhai." There are also rice reduction. Cui Bao also wrote: "In the four years of Yuankang in Xuan Di, Chang 'an was rainy and black millet. "History of Song Dynasty" and "Records of Five Elements" also said: "In June, it rained in Yuan You, Tujing Town, Linjiang County; It was rainy and dark in July. "Similarly," History of the Yuan Dynasty and Five Elements "contains:" In October of the eleventh year of the Yuan Dynasty, it rained like millet in the northeast of Quzhou; Shao Wuyu black millet, such as reed; Xinzhou is rainy and dark, and there are many counties and townships. People take it and eat it. "There is rain millet again. Cui Bao said: "In the fourth year of Jianyuan, it rained heavily." "Xuandi Festival for three years, Chang 'an rain black millet." Of course, there are also rain wheat. Zhang Hua's "Natural History" in the Jin Dynasty contains: "When Emperor Wu of the Han Dynasty, wheat fell in the county." There are many similar records in local county annals. I haven't checked them one by one, so I won't list them here.

If you only read the books mentioned above, you can't find all kinds of other interesting stories about rain. Actually, twenty.

There are countless materials in the five history notes novels. Then open the History of Han Dynasty and the Records of Five Elements, which wrote: "In August of the second year of Yong Guang, it rained grass in Yuan Di, but the leaves were cemented as big as a projectile." This can be called grass rain.

In addition, Cui Bao also said: "Han Emperor Yonghe Zhong, Chang 'an Yu Mian, are all white." He also said: "Xuan Di Yuankang was born in Nanyang for four years.

Rain bean. "History of Song Dynasty" and "Records of Five Elements" also contain: "In June of the second year of Yuanfeng, Zhongzhou was in the capital; In July, Wu Jia, Yudu, Nanbin County. " These examples of rain, bean rain and so on can show that when it rains, there are still many things that can fall with the rain, not just what we are talking about.

② reasons

So, how to explain this phenomenon? Are these supernatural phenomena? Obviously not. These phenomena are actually caused by cyclones. Cyclone, also known as return air, has long been known by the ancients.

Li, an astronomer in the Tang Dynasty, was quoted in the book "The Outline of Peeping" in the Ming Dynasty: "The return air suddenly rises, but turns like a horn, turns upward, and those who rise from top to bottom or grind the ground are collectively called return air." When the return air blows, sand and stones fly, rise from the ground and go straight to the sky. So things on the ground are often blown to the sky, far away, and then fall to the ground. In this way, the so-called strange phenomena such as Yu Qian and Jin Yu have been formed.

In fact, the reason for these phenomena is very simple.

When we go to the countryside, we often see a whirlwind rolling up sand and turning it into a yellow dragon. It is said that if people are in the center of this tornado, it is very dangerous. Even the birds in the sky can't escape when they meet this tornado. Therefore, "History of the Song Dynasty and Five Elements" said: "In December of the second year of Qingyuan, a million copper coins flew to Jin 'e Township, Wuxian County. "Of course it was blown away by the whirlwind." "Continued Literature General Examination" contains: Ming Dynasty, Hongwu eight years, Ku Qianfei. At that time, there was money on the houses of the people in Nantai, and every bamboo, or ten or twenty, was money. Jiang Yikui's Chang 'an Hakka Dialect in the Ming Dynasty also wrote: "The old tower in Zhuozhou is in Sanggan River, which is a famous town tower. In the first year of Jiajing, the tower collapsed and there were ancient coins in it, all of which flew empty. " When these records are connected with the examples mentioned above, the truth of the problem is very clear.

From the anecdote of rain, we can easily know that there are many strange phenomena, and there are some reasons as long as we study them carefully. Therefore, we should not erase all kinds of records left by the ancients, even including many records of supernatural beings, but should look for useful things from them.