The second volume of the fourth grade mathematics "Axisymmetric" teaching plan (1) I. Teaching objectives
Knowledge and skills
Can draw an axisymmetric figure, master the methods and steps of drawing: draw several key symmetrical points first, and then connect the lines.
Second, the process and methods
Through observation, operation and other activities, an axisymmetric figure can be completed on grid paper.
Third, emotional attitudes and values
Let students further enhance their hands-on operation ability, develop the concept of space, cultivate aesthetic concepts and interest in learning mathematics in the process of exploration.
Second, the difficulties in teaching
Teaching emphasis: master the methods and steps of drawing.
Teaching difficulty: You can draw the other half of an axisymmetric figure on a square paper.
Third, teaching preparation.
Square paper, courseware.
Fourth, the teaching process
(a) review of imports
Teacher: Students, yesterday we met an axisymmetric figure. Who can talk about its characteristics?
Default value: the distance between the corresponding point and the axis of symmetry is equal.
(2) Explore new knowledge
1, draw an axisymmetric figure.
Teacher: according to the axis of symmetry, complete the following axisymmetric figure.
Teacher: What can I do to draw the other half smoothly? What is the basis?
(Group discussion, classroom communication)
Premise: We have just learned the characteristics of symmetrical points of axisymmetric figures, and we can draw them in this way.
Teacher: Good. How to find some? Did you find all the points?
Default: not counting, only counting the distance from the key point to the symmetry axis; Point out the symmetry point of the key point on the other side of the symmetry axis; Connect the points drawn in sequence.
Teacher: Who can show the other half of the axisymmetric figure you drew?
Students show their works.
2. Report the query results.
Teacher: Students, what did we learn today?
Preset: when drawing the other half of an axisymmetric figure on grid paper, first determine the axis of symmetry, find out the key points, count the distance from the key points to the axis of symmetry, then point out the corresponding points of the key points, and finally connect the corresponding points in turn to draw the other half of the axisymmetric figure.
Teacher: Can you briefly outline the steps of drawing the other half of an axisymmetric figure on it?
Student: after determining the axis of symmetry, find the key points; Calculate the distance by two; Three corresponding points; Four lines.
The design intention leads students to think: the supplementary method of completely axisymmetric graphics is the difficulty of this lesson. After students' full discussion, students can summarize and refine methods through their own practice, which will make their memories more profound.
The second volume of the fourth grade mathematics "Axisymmetry" teaching plan (2) teaching objectives 1. Knowledge and skills:
Further understand the symmetry axis of the graph, and draw the symmetrical graph of the graph on the grid paper.
Second, the process and method:
Through observation, the position of symmetry point is determined, and the characteristics and properties of graphic symmetry are explored.
Third, emotions, attitudes and values:
Let students feel the beauty of axial symmetry in life and know that there is mathematics everywhere in nature.
The focus of teaching is to understand the symmetry axis of graphics and draw axisymmetric graphics.
Teaching difficulties determine the position of symmetry point.
Multimedia courseware for preparing lessons
Teaching methods include observation, explanation, cooperation and communication, and inquiry.
On the Interaction between Teachers and Students in the Teaching Process
First, create a situation
Show an axisymmetric picture
Teacher: Are these pictures nice? Why is it beautiful? There are many objects in our life that make people feel beautiful because of symmetry. Today we will study these beautiful symmetrical figures together. (blackboard writing: axisymmetric figure)
Second, review old knowledge.
1. What other axisymmetric figures have you seen?
2. What is the axisymmetric figure?
3. Look at the pictures in the book and draw the symmetry axis.
Third, explore new knowledge.
1, for example 1 Take a look and count. What did you find? (Guide students to observe)
(1) cooperative exploration
Is this picture symmetrical?
② What does this straight line in the middle mean?
(3) Point A and Point A are two corresponding points in this diagram, and their distance to the symmetry axis is () square.
(4) Point B and Point () are corresponding points, and their distance to the symmetry axis is () square.
⑤ Point C and point () are corresponding points, and their distance to the symmetry axis is () square.
⑥ I found that in an axisymmetric figure, the distance between the opposite points on both sides of the axis of symmetry and the axis of symmetry ().
(2) Reporting and communication:
① In an axisymmetric figure, the distance between opposite points on both sides of the axis of symmetry is equal.
② We can use this property to judge whether a graph is symmetrical or not. Or draw symmetrical figures.
2. Example 2
(1) Guide students to think:
First, how to draw? What to draw first? Draw what again?
B.how long should each line segment be drawn?
(2) On the basis of thinking, try to draw with a pencil.
(3) Summary:
① Find out the key points of a given graph.
② Statistic or measure the distance between the key points of the figure and the symmetry axis.
③ Find the symmetry point of the key point on the other side of the symmetry axis.
(4) According to the given figure, connect the points in turn to draw an axisymmetric figure of the given figure.
Fourth, classroom exercises.
P84 Do the second question.
Verb (abbreviation of verb) course summary
What did you learn from this course?
1. In an axisymmetric figure, the distance between the opposite points on both sides of the axis of symmetry is equal.
2. We can use this property to judge whether a graph is symmetric. Or draw symmetrical figures.
Graphic Motion of Blackboard Design (2) Axisymmetric (1)
The method of drawing axisymmetric figures with known figures on square paper;
1, find out the key points of the given graph.
2. Calculate or measure the distance from the key point of the figure to the symmetry axis.
3. Find the symmetry point of the key point on the other side of the symmetry axis.
4. According to the given figure, connect the points in turn and draw the axisymmetric figure of the given figure.
Teaching reflection This lesson starts with the figure with axisymmetric characteristics and guides students to summarize the definition of axisymmetric figure. Then, by making pine graphics, the characteristics and properties of axisymmetric graphics are found out, so that students can experience the process personally and deepen their understanding of axisymmetric graphics.