Physical phenomena in China's poems

Nature is rich and colorful, and ancient poets left a well-known poem when they experienced life, observed and appreciated the beautiful scenery of nature. And because physical phenomena are everywhere in nature. Therefore, some physical phenomena inevitably appear in ancient poems. Specifically, these seemingly chaotic phenomena belong to different branches of physics, including the most common light phenomena and sound phenomena. Of course, some phenomena are closely related to classical mechanics and kinematics. The poet's meticulous description of life makes these scientific phenomena hidden between the lines of the poem, which triggers our thinking today. Light is the most common phenomenon, and it is believed that light is closely related to our lives, whether ancient or modern. Let's talk about the phenomenon of light first.

The second part (light phenomenon in ancient poetry)

Humans began to observe and study light very early, and gradually accumulated rich knowledge, making optics one of the earliest branches of physics. Mojing was written 2400 years ago and is the earliest optical work in the world.

The most basic property of light is linear propagation. "Until I raise my cup, I ask the moon to bring me my shadow, so that the three of us can drink with the moon" is one of Li Bai's words. When the poet was drinking, a little moonlight reflected his shadow, as if there were three. In the psychedelic of light and shadow, the relationship between them can be faintly seen. How can the "bright moon" become an "opposite shadow" and how can there be "three people"? Due to the linear propagation of light, the light emitted by a point light source (here we roughly regard the "bright moon" as a point light source) shines on an opaque object (person), and the object is irradiated on the surface of the light, forming a dark area behind the backlight surface that cannot be irradiated by light, which is the shadow of the object. Of course, because the luminous surface of the "bright moon" is relatively large, every luminous point on the luminous surface can be regarded as a point light source, and they all produce a shadow area behind the object. Some areas of these shadows are completely unaffected by light, which is called umbra. There is also an area around the umbra that can be illuminated by part of the light emitted by the light source, which is called penumbra. Therefore, the phenomenon of "bringing my shadow to me and making us three" is caused by umbra and penumbra. Li Bai not only has the heroic spirit of "raising a glass, I ask the bright moon", but also observes and sees "bringing my shadow to me and making us three" in detail. This poem is the concrete unity of the poet's thoughts and feelings and scientific phenomena. Du Fu also combined light, shadow and starry sky perfectly in Pavilion Night. "Stark blows the fifth watch, challenging the gongs and drums, and the stars and Tianhe pulse across the three mountains", which reminds people of the beautiful Milky Way and the steep scenery of the Three Gorges.

The refraction and reflection of light is also a phenomenon of light that people realized earlier. The poet Li Bai also observed the refraction and reflection of light.

Phenomenon. A poem "Lushan suggestion and Lu Xuzhou" wrote: The beautiful scenery of "Jiudieping Scenic Resort" and "Yunjin", the mountain seat containing phosphorus and the clouds in the sky are reflected in the mirror-like water, and the lakes and mountains are full of interest. The reflection of mountains and clouds in water is the result of light reflection. Whether it is a transparent object or an opaque object, its surface should reflect some light. When a plane is illuminated by parallel light, the reflected light is also parallel. This kind of reflection is specular reflection. Here, we can take the "Ming Lake" in the poem as a mirror. The light emitted from point S, after being reflected by a plane mirror, seems to be emitted from point S', which is called the image of S. The "shadow" and "looking at the light" seen by the poet from the water are the images of the lake reflecting the mountains and clouds. To the observer on the water, it seems that there is a reflection point S' underwater, but in fact, S' does not exist. Of course, this kind of poems describing the reflection of light also include Li Bai's Song of Autumn Pu, Autumn Frost in the Mirror, and Harmony between Little Blue Island and Heaven.

"Sailing alone, the sky has gone, only the Yangtze River flows in the sky." This is a famous sentence in Li Bai's Farewell to Meng Haoran on the way to Yangzhou. The poet's infinite concern for his friends is pinned on Lonely Sail and Far Shadow. The "blue sky" in the atmosphere is the result of light refraction. When light enters another medium from one medium, at the junction of the two media, part of the light enters the latter medium, changing the original propagation direction, which is the refraction of light. The closer the atmosphere covering the earth's surface is to the ground, the greater the density and the higher the refractive index. In this medium with uneven density distribution, light does not travel in a straight line. We can generally think that the air on the surface of the earth is composed of many horizontal gas layers, and the density of each layer is different. Of course, the closer the plane is to the horizon, the more obvious the deflection of light in the atmosphere. So Li Bai said it was "exhaustion of the sky".

There is also a special phenomenon in refraction-total reflection. "The moon rises like a mirror, and the sea clouds shine like palaces." Li Baizhen has a good eye. He also saw the phenomenon of total reflection in the air-a mirage. Under the exaggerated style, a looming mirage seems to emerge in front of you. It is also caused by the propagation of light in uneven air. When the air pressure is constant, the air density decreases with the increase of temperature, and the refractive index of light also decreases. In summer, the temperature on the sea surface is lower than that in the air. When the light emitted by distant peaks and pavilions shines into the air, because the refractive index of the lower air is greater than that of the upper air, the light continuously refracts and deviates from the normal direction more and more, and enters the hot air.

The incident angle of this layer is increasing. When the incident angle of light increases to the critical angle, total reflection will occur, and people will see distant scenery hanging in the air.

Above, we saw the appearance of light phenomenon in combination with ancient poems, and briefly explained its principle. The poet combines what he has seen and heard in life with wonderful scenery and sincere feelings, and presents the mystery of nature to us completely. Next, let's take a look at how the sound phenomenon and other phenomena are integrated into the scene of ancient poetry.

The third part (sound phenomenon and other phenomena in ancient poetry)

In addition to the changeable light phenomenon, there are many wonderful sound phenomena and mechanical and kinematic phenomena in life. Poets love life and always pay attention to every detail in life. Of course, they also pay attention to these physical phenomena in daily life and show them in their poems. Everyone is familiar with the poem "Hanshan Temple outside Gusu City, the midnight bell arrives at the passenger ship" in a night berth near Fengqiao. This famous sentence, which has been told through the ages, also contains sound phenomena.

We live in a world full of sound, and people transmit information to each other through sound. As we all know, sound is produced by the vibration of objects. There is a poem in Meng Haoran's Old Tour of Guangling in Lujiang: "Leaves on both sides of Feng Ming." Doesn't that explain this truth? Of course, due to the limited level of science and technology at that time, the ancients did not realize that sound was a wave, that is, sound waves. There is a medium for transmitting vibration between sound waves and human ears-air. The vibration of the sound source changes the density of the surrounding air, forming a longitudinal wave with alternating density, which is the sound wave. The energy of sound wave vibration is introduced into people's ears through sound waves, which makes the eardrum vibrate and people produce it.

Gave birth to the feeling of sound.

Because of the nature of sound waves, wave interference and diffraction will occur, and wave reflection will also occur. The reason why I heard the "midnight bell" was the result of sound wave diffraction. The wavelength of sound wave is between 1.7 cm and 17 m, which can be compared with the size of ordinary obstacles, so we can bypass ordinary obstacles and let us hear the sound on the other side of obstacles.

The reflection of sound waves is a very common phenomenon. When we speak, sound waves will reflect back when we meet obstacles. "Cold rock full of empty forest" is a true portrayal of sound wave reflection.

Matter is in constant motion, so physical phenomena produced by material motion are also widespread in daily life. Poets are people who are dedicated to their lives. These movements cannot escape their eyes and are vividly portrayed in their works. Li Baizhen deserves to be a model in this respect. He wrote: "Moonlight is my escort home." It depicts the relative movement between the moon and people on the hillside. Because all objects are in motion, when studying the motion of an object, it must be assumed that an object is stationary, and the object that is assumed to be stationary for studying the motion of an object is called a reference object. In his poem, Li Bai assumes that the earth is motionless, that is, taking the earth as a reference, people and the moon move in the same direction. "Friends are hard to meet, but as for the stars in the morning and evening" is a famous sentence in Du Fu's "Giving Eight to Wei", which also incorporates the physical phenomenon of chasing sports into the poem. If two objects move in the same direction at the same speed, it is impossible to catch up. In Moonlit Night, Liu Yunping also described the pursuit movement with the stars as the reference, that is, "the moonlight is half full, and the big dipper fights south." .

The fourth part (summary)

Above, when we read ancient poems, we discussed some common simple physical phenomena in life. When we walk into the wonderful artistic conception depicted in ancient poetry, we also enter the unfamiliar material world. If ancient poetry is a pot of wine, then physics is the best appetizer. After "drinking" and "eating", I also learned a lot and improved my literary accomplishment. Reading more ancient poems can cultivate sentiment, learn knowledge and arouse thinking, which is very beneficial. China's poems are rich and colorful. As long as we deeply explore its mystery, we will enter a rich and colorful world.

How to explain the "smoke" in the poem "Purple Smoke from Rizhao Incense Burner"

Wanglushan Waterfall

li po

Rizhao incense burner produces purple smoke,

Looking at the waterfall hanging in front of Sichuan.

Flying down from 3,000 feet,

It's been nine days since I suspected that the Milky Way had set.

To annotate ...

1. Lushan Mountain: Located in the south of Jiujiang City, Jiangxi Province, it is a famous scenic spot in China.

2. Incense burner: that is, incense burner peak, in the northwest of Lushan Mountain, named after it is shaped like incense burner and often covered with clouds in the mountains.

3. Hanging Qianchuan: Hanging on the water in front.

4. Nine days: According to ancient legends, the sky has nine weights, and nine days is the highest level of the sky.

Brief analysis

This is a landscape poem written by the poet Li Bai when he lived in seclusion in Lushan Mountain at the age of about fifty. This poem vividly depicts the magnificent scenery of Lushan Waterfall and reflects the poet's infinite love for the great rivers and mountains of the motherland.

The first sentence is "Purple smoke from the Rizhao incense burner". "Incense burner" refers to the incense burner peak of Lushan Mountain. This peak is in the northwest of Lushan Mountain, with a sharp and round shape, like a censer. Because of the waterfall, water vapor transpiration, in the bright sunshine, as if there is an indomitable spirit incense burner, purple smoke rises in Ran Ran. A word "life" brings the scene of smoke rising to life. This sentence set a magnificent background for the waterfall, and also rendered the atmosphere for the following direct description of the waterfall.

The second sentence is "overlooking a thousand waterfalls in Sichuan". The word "overlooking the waterfall" takes care of the title "overlooking the Lushan waterfall". "Hanging thousands of rivers" means that the waterfall is like a huge white practice, hanging straight from the cliff to the river ahead. The word "hang" changed from dynamic to static, and Visha wrote about the waterfall in the distance.

The first two sentences of the poem outline a panoramic view from the big picture: purple smoke fills the air at the top of the mountain, white practice hangs in the mountain, and rapids rush down the mountain, forming a magnificent picture.

The third sentence "Flying down three thousands of feet" is a detailed description of the waterfall at close range. "Flying Flow" shows that waterfalls come out in the air and spew out. "Straight down" not only describes the steepness of the rock wall, but also describes the rapidity of the water flow. "Three thousands of feet" is an exaggeration, describing towering mountains.

In this way, the poet felt that the majestic momentum of the waterfall had not been fully displayed, so he went on to write a sentence, "It is suspected that the Milky Way has fallen for nine days." It is said that this waterfall "flew down", which makes people suspect that the Milky Way poured down from nine days. A "doubt" is ethereal and lively. If it is true, it makes people daydream, which adds to the magical color of the waterfall.

This poem is very successful in metaphor, exaggeration and imagination, with unique conception, vivid language and bright washing. Su Dongpo appreciates this poem very much, saying that "the emperor sent the Milky Way to fall into the pulse, and there were fallen immortals in ancient times." The "immortal" is Li Bai. Looking at Lushan Waterfall is indeed an example of body description and lyricism.

About the author: Li Bai (70 1-762) was a great romantic poet in the Tang Dynasty. He wrote many poems praising the motherland, exposing the darkness of society and despising the powerful. His poems have a far-reaching influence on later generations.