Textbook Analysis:

The article "Why Are Flowers So Red" introduces the scientific knowledge about why flowers appear red, explaining that the red color of flowers is due to various conditions of its own and needs, as well as the results of natural, artificial and other factors. The teaching of this article is mainly based on students' self-study, allowing students to grasp the text as a whole and understand the reasons for the "red" flowers. Through cleverly designed questions, students are guided to understand the rigorous and natural explanation sequence of the article, learn to use appropriate explanation methods, and analyze the accuracy, rigor and accuracy of the article. Vivid language features.

Teaching objectives:

1. Perceive the text content as a whole and understand the reasons for "why the flowers are so red".

2. Clarify the structural level of the article and learn how to explain things in a logical sequence.

3. Further understand the basic characteristics of expository writing and master the relevant knowledge of expository writing.

4. Cultivate a concern for nature, love for science, and a spirit of courage to explore.

Teaching focus:

1. Perceive the text content as a whole and understand the reasons for "why the flowers are so red".

2. Clarify the structural level of the article and learn how to explain things in a logical sequence.

Teaching difficulties:

1. Further understand the basic characteristics of expository writing and master the relevant knowledge of expository writing.

2. Cultivate a concern for nature, love for science, and a spirit of courage to explore.

Teaching method: group cooperative inquiry

Teaching media: multimedia

Teaching process:

1. Introduction of interest

< p>Students, nature brings us many beautiful scenery. Whenever spring comes, various flowers in nature bloom one after another, colorful and colorful. Now let's take a look at a set of pictures. (Show pictures) Students, when you look at these beautiful flowers, when you enjoy the fragrance these flowers bring to you, have you ever thought: Why are these flowers so red?

Today, let's study together the explanatory essay "Why the Flowers Are So Red" written by popular science writer Mr. Jia Zuzhang, and let's explore this mystery together.

2. Knowledge Review

Question: Where should we start when learning expository writing?

Clearly:

1. Distinguish the types of explanations

2. Master the explanation objects

3. Grasp the characteristics of the explanation objects

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4. Clarify the order of explanation

5. Judge the method of explanation

6. Analyze the accuracy of the expository language

3. Learning objectives< /p>

1. Perceive the content of the text as a whole and understand the reasons for "why the flowers are so red".

2. Clarify the structural level of the article and learn how to explain things in a logical sequence.

3. Further understand the basic characteristics of expository writing and master the relevant knowledge of expository writing.

4. Cultivate a concern for nature, love for science, and a spirit of courage to explore.

4. Check the preview

Can you pronounce these words correctly?

Burn ( ) hurt naked ( ) wither ( ) secretion ( )

hibiscus ( ) flower ( ) poppy ( ) beauty triangular ( ) mirror

Faded ( ) Citrus ( )

5. Independent learning

Read the text silently. In what aspects does the text explain the question "Why are the flowers so red?"

Material basis (2-4) (2) Principles of physics (5) (3) Physiological needs (6)

(4) Evolutionary perspective (5) Natural selection (8) -9) (6) Manual selection (10)

What is the explanatory structure of the text? (Total - Points - Total)

6. Collaborative exploration

1. Can the order of the six reasons be changed? Why?

Clear: Of the six aspects explained in this article, the first four are internal factors of bonuses, while the last two are external factors. External factors must work through internal factors, so internal factors are the main ones. External causes are secondary. This order of writing according to the inherent priority of things is a commonly used order in explanatory essays. We call it logical order.

2. Can the order of the four internal factors be reversed? Why?

(First of all, it is necessary, and... according to the internal rules, the logical order from primary to secondary.)

3. Read 2- —Paragraph 4, thinking:

Why do flowers appear red, yellow and white?

Safflower: Contains anthocyanins converted from glucose in its cell fluid. When the cell fluid is acidic, anthocyanins appear red...

Yellow: Because it contains carotene in its body.

White flower: Its color is white because there is no pigment in its cell fluid.

4. In paragraph ④, the author gives an example - "Tianse Hibiscus". What are its characteristics?

(Can change color: Every hibiscus flower will go through such a process: white in the morning, red at noon, and dark red in the afternoon.)

Add color hibiscus three times a day Change, why is this example not placed first?

(After introducing the flowers of three colors before, let’s take this flower that changes color, from general to special, showing the strictness of the explanation.)

7. Focus on study

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The article not only uses a rigorous and natural order of explanation to explain things, but also uses explanation methods.

1. Read paragraph 10 aloud, find out the explanatory methods used in this paragraph, and talk about their role in the text.

Give an example: clearly, truly and powerfully explain the results achieved by artificial selection in a relatively short period of time.

Column numbers: Accurately and specifically describe the results achieved by manual selection in a relatively short period of time.

For comparison: it highlights the results achieved by artificial selection in a shorter period of time.

2. For example, peonies are wild original species that took hundreds of millions of years to create. Their flowers are single-petaled and only pink in color. After artificial cultivation, just for the period in the middle of the Northern Song Dynasty (eleventh century), it took several decades to... wait for different postures.

Understand the expressive role of "only" and "only" in sentences.

("Only" emphasizes that it is limited to the pink variety. The word "only" indicates a very short time, indicating that artificial selection speeds up the process of bonus. The word "just" emphasizes that artificial cultivation takes place in a very short period of time. Create colorful and colorful flowers in a short period of time)

(Language characteristics: accurate and strict)

3. This is a popular science explanatory article to popularize scientific knowledge and let the readers know more about it. Readers like to read, so it must be vivid. Where is vividness reflected? (The first paragraph is the title of the article)

8. Summary

After studying this popular science expository article, what knowledge have we learned about expository writing?

Explain the structure total - points - total

Explain the sequence from inside to outside, from primary to secondary logical order

Explain the method and give examples and numbers for comparison

Explanation language is accurate, rigorous and vivid

9. Expansion and extension:

1. Why are the flowers so red? What does "red" mean? (Referring to the colorful colors of flowers) Why does the author use red to represent colorful flowers? (Red is a passionate color, it is strong, unrestrained, and invigorating.)

2. What rhetorical techniques are used here? (Clearly: asking questions) The author asks "Why are the flowers so red" many times in the text? What is its purpose?

(The question appears 7 times in the article, with repeated intervals, making the center prominent, the context clear, and the rhythm bright, adding to the beauty of the language and the artistic color of the article.

There are three The role of aspects: First, it raises questions by grasping the familiar characteristics of flowers, which helps to reveal the center of the article; second, it sets up doubts and interest and is attractive; third, the main part of the article focuses on six aspects Explain the reasons why the flowers are so red, starting with "Why are the flowers so red", which makes the article clear and fast-paced, adding artistic interest)

3. The text title is borrowed. This is the name of an interlude in "Visitors from the Iceberg". Do you think this is a good title? Can you give any other similar examples?

(1) As a title:

Clearly: first, it reminds the content to be explained in the text; second, it arouses the reader's interest in reading and curiosity.

This method of formulating topics gives us inspiration for formulating topics when writing essays. We can quote poems, lyrics, famous quotes, etc. to formulate topics to attract readers' attention and stimulate reading interest.

(2) Quotes: "Looking from side to side, a ridge becomes a peak", "Passing by with a smile", "Go home often", "How can you see a rainbow without going through wind and rain", "Happy Hometown", "I love my home" 》

Translations: "It's all the fault of the wind and sand", "We share the same journey with wind and rain", "Worrying about water in vain", "Success is precious, but the price of education is higher"

Quote or transliterate Using familiar poems, song titles, lyrics, famous sayings, sayings, book titles, film and television drama titles, advertising titles, etc. as the title of the article can make the title of the article appear novel and unique, and produce a unique charm.

Students must learn to use this question-writing technique.

4. Jia Zuzhang is a biological science popularization writer. He explains to us a "why" in nature. Students must have read books like "One Hundred Thousand Whys", and you must also know many "whys" in nature.

The teacher will give a few examples: Why can bats fly at night? (Because bats fly not by eyes, but by ultrasound.) When it rains, why do we often see lightning first and then hear thunder? (Because sound travels slowly.) There are many whys in life. You can find information after class or ask relevant professionals to answer them.

10. Homework

1. There are many "whys" in life. Please tell your classmates the "why" that interests you most and feels novel. Search for information after class. listen.

2. Read "One Hundred Thousand Whys·Plant Volume".