The title of Lesson 20 [The Illusion of the Setting Sun] in the first volume of the Chinese textbook for eighth graders

The Illusion of the Setting Sun

1. Basic knowledge

1. Please phoneticize the following bold words or write Chinese characters according to pinyin.

Emergency ( ) Gorgeous ( ) Decay ( ) (yān) Red (zhuì) Fall

Dust (āi) (wèi) Blue darkness (hú)

2. Write the words according to their meaning.

(1) The sun is going to set. ( )

(2) Bright and beautiful (mostly used to describe scenery) ( )

3. According to the text, fill in the appropriate words on the horizontal lines.

(1) The sunset is indeed beautiful and varied.

(2) Astronomers have long discovered that the earth’s atmosphere causes light to leak.

(3) When the sun's rays close to the horizon pass through the atmosphere, the distance is much greater than that of the upper layers, so the light entering the lower layers reaches quickly.

4. One of the following sentences that does not use explanation method is ( )

A. Most of these strange scenes are illusions, and the sunset itself does not change at all.

B. Generally speaking, there is more smoke and dust in the air at dusk than in the early morning. Here, the color of the setting sun is different from that of the rising sun.

C. This is because when light passes through the air, its speed slows down by 87 kilometers per second, so the refraction of light also changes.

D. (The sun at sunset) is like a huge jade plate hanging far away from the sky.

5. Read the following materials. What did you find out from them? Write the results of your inquiry.

American biologists once conducted such an experiment: newborn babies were divided into four groups. One group could not hear any sound; the second group played a recorded lullaby; the third group used a metronome to imitate the sound; The group plays a recording of the mother's heartbeat. The results showed that the babies in the fourth group were able to fall asleep peacefully in half the time it took the other three groups. The babies in the first group cried and were restless up to 60% of the time.

2. Overall content

6. This is an article explaining things. Please fill in the table below based on the text content to clarify the order of explanation in the article.

Hallucination at sunset

Causes of hallucination

7. The language of this article is vivid, aesthetic and literary, and it uses description appropriately. The expression method enhances the expression effect of the article. Please extract two such sentences from the text.

3. Key paragraphs

Read the following and answer the questions.

In fact, the sunset is as spectacular, beautiful, mysterious and charming as the sunrise. If you have the opportunity to watch the sunset, it will fascinate you: the sun lies quietly on the western horizon, becomes so big, and its color is so deep yellow and bright red; it falls slowly, and shrinks and becomes flat as it approaches the horizon. If there are clouds in the sky, you will see a brilliant sunset; if there are no clouds in the sky, don't forget to look back. You will find a mysterious blue dark arc in the sky behind you, and there is an obvious bright arc outside the dark arc. While the dark arc and bright arc rise, a charming purple light will appear in the western sky. As the sun sets, the purple light moves downward and disappears when it approaches the horizon. Unfortunately, this beautiful purple light is rare.

The sunset is indeed beautiful, colorful and varied. But viewers would not think that most of these strange scenes are illusions, and the sunset itself does not change at all.

Astronomers have long discovered that the Earth's atmosphere scatters light. In 1871, British scientist Duanli proved that the scattering of short-wave light is much stronger than that of long-wave light. Therefore, the short-wave light in the sun - purple light - is scattered by tiny dust and air molecules in the atmosphere 10 times stronger than the long-wave light - red light. times more than that (which explains why the sky is always blue in the first place). Because at sunset and sunrise, the atmosphere that sunlight penetrates thickens, and yellow and red light have the greatest penetration ability, so the sun looks deep yellow and red at this time. Generally speaking, there is more smoke and dust in the air at dusk than in the morning, so the color of the setting sun is different from that of the rising sun.

Since the earth's surface and atmosphere are both curved, when the sun's light near the horizon passes through the atmosphere, the distance is much greater than that at high levels, so the light entering the bottom layer is rapidly attenuated. In addition, after the sun sinks into the horizon The resulting shadow of the Earth appears as a blue-gray dark arc in the sky; while the upper atmosphere is less dense and light scattering is weak, resulting in a bright arc on the dark arc. This wonderful atmospheric optical phenomenon rises toward the zenith as the sun sets, and disappears as darkness falls. As for the beautiful purple light, it is produced due to the superposition effect of the human eye, which superimposes the red light passing through atmospheric dust and the blue scattered light of the purer air in the upper atmosphere.

8. The first paragraph mainly uses the expression of . The advantage of writing this way is .

9. The second paragraph belongs to in structure and plays a role in content.

10. What explanation method is used in the underlined sentence in the third paragraph? What are the benefits of writing this way?

11. What does the underlined “this wonderful atmospheric optical phenomenon” in the fourth paragraph refer to?

4. Expansion training

Exploration questions

12. Comparison: Understand the difference in the expression effects of the two sentences in each group.

(1) People love to watch the sunrise and all admire the spectacular scene when the sun rises.

People love to watch the sunrise and admire the spectacular scene when the sun rises.

(2) Unfortunately, this kind of beautiful purple light is rare.

But this beautiful purple light is rare.

13. The hallucination mentioned at the end of the article does not give the reason for the hallucination. Can you try to explain it based on your accumulated knowledge?

Reading questions

Read the following and answer the questions.

Why does the bottom of the rocket look like a trumpet?

Why should the nozzle of the rocket engine be shaped like a trumpet? Let’s start with the special structure of the rocket engine.

The reason why the Fire Simple Engine can produce powerful propulsion is because of the special structure of the rocket engine.

The thrust chamber is the core part of the rocket engine and generally consists of the head, combustion chamber and nozzle. The function of the head and the combustion chamber is to make the combustion agent flow through the combustion chamber and the inner sleeve of the nozzle, cool the combustion chamber and the nozzle, and then spray the combustion agent from the nozzle and the combustion chamber outer sleeve through the nozzle into the combustion chamber, and It is fully burned under the action of the oxidant injected from other nozzles at the same time, converting all the chemical energy of the propellant into thermal energy, producing high-temperature and high-pressure gas of 2200°C-3500°C in the combustion chamber; the function of the nozzle is to transfer the high temperature of the combustion chamber The high-pressure gas accelerates from tens of meters/second to several kilometers/second, thereby converting the thermal energy of the gas into the kinetic energy of the gas, obtaining direct reaction force, and the greater the push.

So, how does the rocket engine obtain such a high injection velocity of gas flow? This is a design science, which is to make the nozzle part of the thrust chamber into a trumpet shape that first converges and then diffuses. The upper end of the convergence section is smoothly connected to the lower end of the combustion chamber. This structure allows the speed of the gas flow to change due to changes in the cross-sectional area of ??the nozzle, allowing the air flow to accelerate from subsonic speed to sonic speed until it accelerates to sonic speed. Therefore, people call this trumpet-shaped nozzle a supersonic nozzle. Since it was invented by the Swede Laval, it is also called the "Laval nozzle".

Let us analyze the principle of Laval nozzle. The gas flow in the rocket engine is used backward through the nozzle under the pressure of the combustion chamber and enters the contraction section of the nozzle. At this stage, the gas movement follows the principle that "when fluid moves in a tube, the flow velocity is high in small areas and small in large areas." On the contrary, the larger the cross-sectional area, the faster the flow rate. In the expansion section, the speed of the gas flow is further accelerated to 2-3 kilometers/second, which is equivalent to 7-8 times the speed of sound, thus generating huge thrust.

Now you should understand that the Laval nozzle actually acts as a "flow rate increaser". In fact, not only rocket engines, but also missile nozzles are in the shape of a trumpet. Therefore, Laval nozzles are widely used in weapons.

(Selected from "China National Defense News" on July 6, 2002)

14. The explanatory object of this article is , and the author adopts the order of explanation.

15. The whole text uses the structure to explain the characteristics of things. The first and second paragraphs are , and the third, fourth and fifth paragraphs are .

16. The selected article introduces things that are not common to us. Can you understand it? Try to talk about the characteristics of article language from one perspective.

17. Setting off fireworks during the Spring Festival is a traditional habit of the Chinese nation. Based on the introduction of this article and your existing knowledge, let’s talk about the principle behind how fireworks can take off and explode.

Interesting questions

18. Idiom pairs.

(1) In order ( )

(2) Impregnable ( )

(3) Help in times of need ( )

(4 ) Last forever ( )

(5) Carefully crafted ( )

(6) Sharp-tongued ( )

Synchronized high school entrance examination

Read below and answer the questions.

If you can watch the sea glow at night, it is quite magnificent. It looks like thousands of stars, like a patch of milky light, and even more like colorful fireworks. People call this phenomenon "sea fire". Who caused this fascinating scene? Whose masterpiece is it?

There is a kind of sea luminescence that appears in the spray foam around and at the stern of sailing ships. This is mainly caused by luminescent plankton with very small particles. It itself is mostly rose red, and usually, it can shine slightly with the help of a fatty substance in its body.

The characteristic of luminescence is that it consists of countless white, light green or light red flashes. But they are usually only noticeable when there are mechanical disturbances in the sea surface or when they are chemically stimulated. When sea waves push them toward the gravelly shore, they are even more triggered to glow. The light emitted is like a bunch of sparks flying around, falling like "fire rain", one after another. Such sea glow is called spark-type sea glow.

There is also a kind of sea luminescence caused by marine luminescent bacteria. Their luminous intensity is weak, and their characteristic is that no matter what the sea conditions are, and no matter whether there is any external disturbance, as long as there are a large number of these luminous bacteria, a milky white glow will appear on the sea surface. Such bacteria are mostly found in estuaries, harbors, and intersections of warm and cold currents, especially where sewers enter the sea or where sea water is polluted. This kind of sea glow is called diffuse sea glow.

Another type of sea luminescence is caused by larger luminous organisms in the ocean, such as jellyfish, sponges, broodworms, ring worms, and scale clams. There are special light-emitting organs on the body of jellyfish, which will emit a large flash of light when stimulated. Some fish can secrete a special substance in their bodies, which reacts with oxygen to emit light. This kind of luminescence usually appears in isolation, and is more eye-catching when stimulated by mechanical or chemical effects. The characteristics of the sea light they emit are bright and dark, and cycle repeatedly. This kind of sea luminescence, like a flashlight, is called flash sea luminescence.

Hai Guangfa is not only colorful and beautiful, but most importantly, it is closely related to production and construction.

Sea areas with strong sea luminescence can reflect the seascape at night. Therefore, on a moonless night, when a ship encounters sea luminescence, it can cause the captain to have an illusion, leading to sea damage accidents and affecting the safe navigation of the ship. Correctly grasping the sea luminescence can predict the weather. After many years of observation, fishermen in Liaoning and Hebei areas of my country have summarized the folk proverb "Fire is seen in the sea, and wind and rain appear". The sea light produced by the swimming fish exposes the hiding places of the fish, so experienced fishermen use it to catch fish at night.

(Selected from "Chinese Newspaper")

19. Please briefly summarize the causes of the colorful, beautiful and attractive "Sea Shining".

20. What are the characteristics of different types of sea luminescence?

21. Why does "spark-shaped sea glow" appear "in the spray foam around and at the stern of a sailing ship"?

22. What is the close relationship between Haifa and production and construction?

5. Fragment composition

23. Have you ever carefully observed the rising sun or the setting sun? Can you describe this beautiful scenery for everyone with beautiful brushstrokes? Please observe and try to write down what you see and feel. Pay attention to the descriptive techniques of learning articles. No less than 200 words.

(I don’t know if you want the answer, so I’ll give it to you)

Reference answers:

1. yǎn qǐ shuāi Yin Zhui Ai Wei Arc

2. (1) The sun is setting in the west (2) Beautiful

3. (1) Brilliant colors (2) Scattering (3) Attenuation

4. A

5. There is a heavenly and harmonious relationship between the baby and the mother's heartbeat.

6． Briefly

7. Example: ① The sun lies quietly on the western horizon, becomes so big, and its color is so deep yellow and bright red; it falls slowly, and shrinks and becomes flat as it approaches the horizon. ② The sky is cloudless. Don’t forget to look back. You will find a mysterious blue-gray dark arc in the sky behind you. There is also an obvious bright arc outside the dark arc. While the dark arc and bright arc rise, a charming purple light will appear in the western sky. As the sun sets, the harsh light moves downward and disappears when it approaches the horizon.

8． The description is vivid and vivid, making the article more literary

9. Transitional sentences connect the previous and the following

10. for comparison. It clearly and effectively illustrates that short-wave light scatters more strongly than long-wave light.

n． "Due to... bright arc" (beginning of the fourth paragraph).

12. (1) The original text uses a double negative sentence pattern to express a positive meaning. It plays the role of emphasis and emphasizes people's love for the sunrise.

(2) Using "unfortunately" is more emotional than using "but". It can better show attachment to the beautiful scenery and make the article full of interest.

13. Briefly

14. The special structure and logic of rocket engines

15. Total score Overall review Partial review

16. Popular and concise.

17. It is similar to the principle that rocket engines can produce powerful propulsion.

18． (1) Disorganized (2) Dangerous (3) The icing on the cake (4) Infamous for eternity (5) Shoddy work (6) Clumsy tongue

19. ① Caused by luminescent plankton with very small particles. ② Caused by marine luminescent bacteria. ③ Caused by larger luminous organisms in the ocean.

20． ① Characteristics of "spark-shaped sea glow": It is composed of countless white, light green or light red flashes. The light emitted is like a bunch of splashing sparks, falling like "fire rain", one after another. .

② Characteristics of "diffuse sea luminescence"; when a large number of luminescent bacteria exist, a milky white glow will appear on the sea surface. ③Characteristics of "Flash Sea Glow": one light and one dark, cycle repeatedly, just like a flash.

21. Because the particles of luminescent plankton are very small, they only emit bright light when the sea surface is mechanically disturbed or chemically stimulated.

22. ① Affect the safe navigation of ships. ②Can predict the weather. ③It is convenient for fishermen to fish at night.

23. Omitted