First of all, talk about textbooks.

(A), a brief analysis of teaching materials

"Translation and Rotation" is the content of Unit 2 in the second volume of Grade Three Mathematics of Beijing Normal University Press. It is based on students' understanding of front and back, up and down, left and right, and simple figures, which lays a foundation for further learning translation and rotation and related geometric knowledge. Translation and rotation is to explore and understand space and graphics from the perspective of motion change. The textbook pays attention to excavating and using rich and interesting examples around us, fully perceives the different characteristics and universality of translation and rotation, and feels the geometric characteristics of translation through the three mathematical activities of "moving, saying, filling and drawing" to further develop students' spatial concept.

(2) Analysis of academic situation

Students have some perceptual knowledge about translation and rotation in their life, but they can't really understand their characteristics. 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. Most students regard the distance between two pictures as the translation distance.

(C), teaching objectives

According to the above teaching material analysis, considering the existing cognitive structure of students, I will determine the teaching objectives of this lesson as follows:

1. Combine students' life experience and examples, perceive translation and rotation phenomena, and intuitively distinguish these two common phenomena.

2. Let students experience learning activities such as observation, operation and cooperation, so that they can draw simple figures with horizontal and vertical translation on grid paper.

3. Stimulate students' enthusiasm for learning mathematics and feel the close connection between mathematics and life.

(4), teaching emphasis and difficulty:

Teaching emphasis: Perception of translation and rotation.

Teaching difficulty: understanding the distance of translation.

(5) Preparation of teaching AIDS and learning tools: multimedia courseware, mobile boat and grid diagram.

Two. Speaking and teaching methods

According to the above teaching objectives, the focus and difficulty of teaching, in order to let students experience the process of abstracting mathematical models from the real background and geometric figures from the real life space, I mainly adopt the following two teaching methods.

1, Situational Teaching Method: Mathematical situation is an important source for students to master knowledge, form ability and develop psychological quality, and it is a bridge between real life and mathematics learning, concrete problems and abstract concepts. "Translation and rotation" is a common phenomenon in life. In this class, I mainly use life examples to create life situations for students, so that students can feel in the situations; Create an activity situation for students to experience in the situation; Create problem situations, let students explore in situations, and gradually realize the construction of mathematical concepts and methods.

2. Multimedia demonstration method: Teachers use multimedia to dynamically present the translation process, which is convenient for students to observe and understand the direction and distance of translation and break through the difficulties in a vivid way.

Third, theoretical study.

While choosing teaching methods reasonably, we should pay more attention to the guidance of students' learning methods. Let students not only learn, but also learn. In this class, I mainly guide students to learn the following two methods:

1, operation discovery method: educator Suhomlinski put forward: "Children's wisdom is at your fingertips." It can be seen that students' thinking can not be separated from practical activities. In this lesson, it is difficult for students to understand the translation distance. To this end, teachers organize students to operate. Through operation, observation and comparison, students are guided to discover that observing the translation process of a graph only needs to observe the translation process of any point on the graph.

2. Group cooperation and communication method: Cooperation and communication is one of the important ways for students to learn mathematics. In this class, in view of the teaching difficulties, teachers organize students to cooperate in groups twice to provide students with opportunities for communication. Students can fully demonstrate their own thinking process in the group, and at the same time compare their own ideas with others' methods in listening, and discover the rules while understanding and adopting different opinions and methods.

Fourth, talk about the teaching process

(A), the creation of the situation, the initial perception of translation and rotation.

1, class begins, the teacher's dialogue is introduced.

"Son, have you ever been to an amusement park? There are many interesting amusement projects in the amusement park. Today, the teacher will go and have a look with everyone. Courseware display: some dynamic pictures in the amusement park. )

Please observe carefully how these amusement projects have changed. "

2. After the students observed, the teacher then asked: Are these objects moving in the same way? Please classify them according to the way they move and explain the reasons.

The last question, I will let the students communicate in the group first, and then report the communication to the whole class.

3. According to the students' communication, the teacher makes a summary.

Like the cable cars, slides and trains in the amusement park above, they all move along a straight line, which we call translation (blackboard writing: translation); Just like a spinning hut and a windmill (talking and mapping), they all rotate around a fixed point. This movement is called rotation (blackboard writing: rotation).

Today we will learn "translation and rotation" together.

Design purpose: Let students perceive the translation and rotation phenomena in the scene. As advocated by the new curriculum standard, mathematics teaching should be closely linked with students' real life, and vivid and interesting scenes should be created according to students' life experience and existing knowledge, so that students can acquire basic mathematics knowledge and skills and experience the value of learning mathematics.

(2) Further understanding translation and rotation with practice.

In the first part of the study, students only have perceptual knowledge of translation and rotation. In order to help students accurately construct the concepts of translation and rotation, I designed the following three activities:

Activity 1:

The movements of the following objects are translation painting "-"and rotation painting "O". (Courseware demonstration)

Design purpose: Let students judge the translation and rotation phenomena in daily life, experience the thinking process of observation and comparison, and make students understand the movement characteristics of translation and rotation more deeply.

Activity 2:

Illustrate translation and rotation in life with examples.

Design purpose: to make students further understand the essential characteristics of translation and rotation, feel that translation and rotation are everywhere in life, and deepen their understanding that mathematics comes from life.

Activity 3:

Try to do an action that means translation or rotation.

For this activity, I will let the students do it in groups first, and then select representatives to perform for the whole class.

Design purpose: In fact, my design requires students to express the characteristics of translation and rotation with original body language. Deepen the understanding of translation and rotation characteristics.

(3) Hands-on operation to further explore translation.

This link is divided into three steps:

1. Create situations and perceive the direction and distance of translation.

(1), show the courseware to students for observation. (Courseware shows: Rabbits cross the river. )

(2) The teacher asked: What is the motion mode of the ship? What kind of translation is it? How many squares have you translated? The third question, I'll let the students talk in the group first. Then report and communicate with the whole class.

In the communication, students may say that the ship moved 3 squares to the left; It can also be said that the ship moved seven squares to the left. ...

2, hands-on practice, understand the translation distance.

When students have different views on the number of translation grids, I don't give a positive or negative answer in time, but guide students to understand the translation distance through two operation activities.

Business activities 1:

(1), group activities.

Students take a movable boat in the group and reproduce the process of the boat's translation on the grid diagram.

Teacher's question: What did you find?

(2) Through students' operation, observation and comparison, students may find that:

(1) When the boat moved, the rabbits on board moved with it.

② Both red and yellow rabbits moved 7 squares;

The ship moved seven squares, and so on.

For every discovery of the students, I give them an appropriate encouraging evaluation, so that they can experience the joy of success.

(3) After the students draw a conclusion, the teacher demonstrates the process of boat translation again with courseware to verify the students' findings. The courseware shows the process of the ship moving.

Guide the students to draw the conclusion that the translation distance of the rabbit on the ship is the translation distance of the ship.

Through the activity 1, students have got a preliminary understanding of the translation distance of objects. At this time, the distance that students translate the object only stays in the real thing. In order to let students further understand the geometric characteristics of translation, I used a plane figure instead of the real thing and designed the second operation activity.

(1) Operation Activity 2: "Let's talk" (courseware demonstration)

Q: How many squares has the triangle moved down? how do you know Students can draw a conclusion according to the downward translation distance of a point or a line segment on a triangle: the triangle has been translated downward by 1 grid.

Q: Which method do you think can be used to judge the number of squares of triangle translation quickly and well?

Through communication, it is concluded that the lattice number of triangle translation can be obtained quickly and well according to the lattice number of any vertex translation on the triangle. In this way, the surface is realized to the point, and the method is optimized.

(2) Ask the students to quickly judge the following two pictures with the optimized method. (Courseware demonstration)

In which direction did the triangle move a few squares?

Let students realize that observing the translation process of a graph only needs to observe the translation process of any point on the graph.

(3) Students independently complete the "Fill-in". (Show courseware) Let students experience the strategy of observing the process of graphic translation by observing a point on the graph again.

Design purpose: Through "learning by doing", let students actively participate in operation activities, experience the formation process of knowledge, cultivate students' observation ability, thinking ability and spatial imagination ability, and break through the teaching difficulties of this course. Realize the transformation of teaching and learning methods and embody the curriculum values based on student development.

3. Feedback exercise:

After the students correctly understood the direction and distance of translation, I designed the following feedback exercises in time.

Exercise 1: Fill in the blanks. (Courseware demonstration)

Design purpose: By finding the direction and distance of the above three graphic translations, students can deepen their knowledge and further understand translation through doing.

Exercise 2: Draw a picture (show the courseware)

In this exercise, I ask students to discuss a reasonable drawing step that can improve efficiency in the group before drawing.

Design purpose: By making students draw translation maps, students can use their translation knowledge to solve practical problems, which reflects the application value of mathematics.

(4), reflect on understanding.

Class summary I asked the students to summarize themselves: "What have I learned?" "How did I learn?" "What's my problem?"

The purpose of the design is to cultivate students' habit of reflection by allowing them to reflect on the learning process and methods independently. Let it make continuous progress in reflection.

(5) Consolidate and deepen, and expand the application.

I designed interesting exercises and open exercises in this class.

1, fun exercise:

Let students appreciate the beautiful patterns designed by translation and rotation in their lives.

2. Open practice:

I ask students to use translation and rotation after class to design beautiful patterns by drawing, cutting, spelling and pasting.

Design purpose: The above exercises are designed in a solid, interesting and creative way, which is suitable for students with different characteristics. In particular, open practice, with large thinking space and flexible methods, extends classroom knowledge to extracurricular activities, providing students with spare capacity with opportunities to show their creativity and better develop their personality. At the same time, it embodies the popular mathematics education thought of "everyone learns mathematics well" and "different people learn different mathematics".

Five, say blackboard writing

My blackboard writing design is dynamically generated in the teaching process, which highlights the teaching focus of this course. Explain that mathematics knowledge comes from life.

(Attached: Blackboard Design)

Translation and rotation