Brief analysis of teaching materials;

Translation and rotation are the new contact contents for students. Mastering these knowledge is of great significance for students to establish the concept of space and master the mathematical thinking method of transformation. From the cognitive development of children's spatial perception, it is from static spatial perception to dynamic spatial perception of perceptual translation and rotation. The translation and rotation of objects are not unfamiliar in students' life, but as a mathematical concept, it is the first time to meet students. Therefore, the teaching of this course should start with a large number of perceptual and intuitive life examples, so that students can perceive the movement characteristics of translation and rotation on the basis of past life experience, and then master the translation method through observation and thinking, and operate the proven learning method, which will pave the way for learning parallel lines and deducing geometric knowledge such as basic plane figure area calculation formula in the future.

Object analysis:

Students have had some perceptual knowledge of translation and rotation in their life, but they don't know these two special terms, and they won't consciously understand their characteristics. Teaching should guide students to perceive the characteristics of translation and rotation from their favorite life scenes, which can stimulate students' interest in learning. Because the students in this period are in the stage of intuitive thinking, they are often confused by superficial phenomena when observing the translation of graphics.

Teaching objectives:

1, through the observation of life cases, let students understand the translation and rotation of graphics. And can correctly judge these two transformations of graphics. Combined with the actual life of students, the phenomenon of translation and rotation is initially perceived.

2. We can correctly judge the direction and distance of graphic translation on grid paper, and draw the graphic after simple plane graphic translation on grid paper as required, so as to cultivate students' observation ability and hands-on operation ability.

3. Understand the close relationship between mathematics and life and the value of learning mathematics. Preliminary infiltration and transformation of mathematical thinking methods to develop students' concept of space.

Teaching focus:

1. Let students distinguish translation and rotation on the basis of perception.

2, can correctly judge the direction and distance of graphic translation on the grid paper, and can draw the graphic after simple plane graphic translation on the grid paper as required.

Teaching difficulties:

1, which can correctly judge the direction and distance of graphic translation on grid paper.

2, according to the requirements on the grid paper to draw a simple plane graphics after translation.

Teaching preparation: multimedia courseware, "translation" and "rotation" cards, square paper for students' experiments, small house paper, and exercise paper for students' drawing. A schematic diagram of the house moving.

Teaching process:

First, the initial perception of translation and rotation

1, Teacher: Students, many teachers are coming to class with us today. Look how much they care about us! What should we do to them before class? Now listen to the teacher: say hello later.

Student: Hello, teacher!

2. Teacher: What a warm greeting. What sports did you all do just now?

Health: turn around ...

Teacher: Actually, people's life lies in exercise. In our life, many objects are also moving, but in different ways. Let's enjoy the pictures of several objects moving and think while watching them: how do they move? At the same time, let's imitate the appearance of objects in motion and prepare your little hands!

Teacher: Please look at the big screen. (showing pictures).

Students imitate by hand.

4. Teacher: Good. The teacher saw your enthusiasm for learning from the students who just moved here.

Question: Are their movements the same? (Some are the same, some are different) Then please classify them according to the different exercise modes. Talk to each other first.

Students exchange and discuss at the same table.

5. Let students talk about the results and reasons of classification, and establish the representation of translation and rotation.

Teacher: Why is it classified like this?

Student: Put the cable car, elevator and window in the same category, because they all move in a straight line, while the propeller and windmill of the plane rotate.

Health: We classify rotating things into one category. ...

Teacher: Are you the same as this classmate? Watch carefully! Then please give your applause to this classmate and yourself.

6. Teacher's summary: The straight and flat action like just now is a translation phenomenon (showing the card "translation"); Rotating phenomena such as propeller, windmill and rotating chair of an airplane are rotating phenomena (show the card "rotating").

7. Reading theme: translation and rotation.

Design intention: To connect with real life, create familiar life scenes for children, guide students to observe and discover, and fully stimulate students' interest in learning and desire to explore. In the process of classifying according to the different movement modes, students can experience the thinking process of observation and comparison, so as to have a deeper understanding of the movement characteristics of translation and rotation and initially form a clearer representation.

7. Teacher: I heard that everyone has strong imitation ability, so can you demonstrate a translation and a rotation respectively? You can use something else.

Let the children think quietly about how the object moves when it is translated and how it moves when it is rotated. )

8. I want to be a good classmate and stand up as an interpreter. Students come out to show, and other students observe and summarize the characteristics of translation: after the object is translated, its direction and size have not changed.

Students demonstrate the translation movement.

Question: After the object is translated, does its direction and size change?

Health: No change.

9. Demonstrate the rotary motion again.

Teacher: What are the characteristics of an object when it rotates?

Health: rotating around a point ...

10, Teacher: You really learn, so let's judge which phenomena are translation and which are rotation. Do you have confidence? (Do the third question in exercise 10)

Teacher: Listen carefully to the teacher's request first. I hope you can tell the teacher quickly with words and gestures. Is the little hand ready?

1 1, that's nice. What other translation and rotation phenomena exist in our life? For example.

Health: Trains, rising rockets, doors moving left and right … are all translation phenomena, while steering wheels and faucets are all rotation phenomena. Design intention: Let students make an action to express translation and rotation, which is actually to put students in the main position and let them express the characteristics of these two sports modes with original body language, so as to gain positive experience and fully perceive these two sports modes. Through the operation, judgment and discovery of translation and rotation phenomena in life, students can understand the concepts more deeply and accurately, and can correctly distinguish the characteristics of these two mathematical concepts in geometric space, thus breaking through the difficulties in the process of knowledge construction.

Second, hands-on operation, verify the conjecture.

The teacher brought two friends today, red ant and black ant. They are also exercising. Please look at the big screen.

(1) Introduce a short story: "Ants Move" (video courseware, teacher: They move houses in tandem. )

(2) Let the students guess: Which ant walks longer?

Health: ...

Teacher: Why do you count the squares that red (black) ants walk through?

Teacher: I really think it is to find out its corresponding point.

Teacher: The teacher has another question: In which direction did the house move a few squares? what do you think?

Let the students demonstrate on the blackboard.

① Guide students to find the corresponding points before and after translation.

(2) Teamwork, using your favorite method to verify the conjecture.

③ Methods and results of student report verification. Pay attention to the completeness of students' answers. )

(4) Review the method of square number and optimize the learning method. Let students intuitively perceive the translation process of small houses.

(5) Summary: Because in the process of translation, every point in the graph moves the same distance in the same direction. So to know how many squares the figure has moved, just find the corresponding point and count how many squares there are between the two points.

Design intention: Introduce short stories to stimulate students' interest in inquiry. Through the operation verification, let the students know that the distance traveled by each point of the object in the translation process is the same. Knowing how many squares the object has moved, we can grasp the feature points and count how many squares there are between two corresponding points. Let students guess boldly and verify their guesses by themselves, so as to prevent students from mistakenly thinking that the distance between two pictures is the translation distance.

Third, practical experience, consolidate and improve.

1, exercise on page 43 of the textbook 10 question 1.

(1) Teacher: Look carefully and tell me which ship it is. How did you find it?

Student: Translation direction.

Student: Find a corresponding point and count the number of squares moved.

……

(2) Teacher: Why not the other two?

Health: One is that the moving direction and distance are wrong, and the other is that the moving distance is wrong.

Summary: When translating an object, pay attention to the direction and distance of movement, and the distance is determined by the corresponding point.

(Exercise on page 43 of the textbook 10, question 2. ) The small trapezoid moves up 3 squares before drawing. A student came out to design an exhibition.

Teacher: What do you think? Why do you paint in this position?

Health: Go up and find a spot.

Health: Count the squares to find other corresponding points. Then connect each point as it is.

3. Draw a picture after the small trapezoid is translated 8 squares to the left. A student came out to design an exhibition.

Teacher: What do you think? Why do you paint in this position?

Health: ...

Students draw a picture independently and evaluate it with projection.

Summary: When we want to draw the translated object, we must first determine the positions of the points after translation, and then connect the points as they are.

Exercise 4 on page 44 of the textbook 10. Which of the following fish can overlap with red fish through translation? Colour them.

(1) Teacher: Which fish can overlap the little red fish by translation?

(2) Teacher: Why can't others overlap with Xiaoyu through translation?

Design intention: let students solve problems with what they have learned in a pleasant environment and improve their enthusiasm. Let students perceive the process of translation again by manual means. By judging which direction the object has moved a few squares and drawing a picture, we can consolidate our understanding of the translation direction and distance and develop students' concept of plane space transformation.

Self-evaluation, summary internalization.

What did you learn from today's study? What do you think of your study?

Design intention: to create a platform for students to reflect and review, so that students can learn to master the main points of knowledge and develop good study habits. Teachers reflect on the achievement of teaching objectives in listening, so as to obtain more information and serve for improving classroom teaching in the future.

The teacher's summary of the class: Indeed, translation and rotation have brought us a lot of convenience and are closely related to our lives. For example, artists use translation and rotation to draw beautiful patterns; Dancers, with translation and rotation to jump out of the beautiful dance; Engineers have created many great miracles through translation and rotation.