1. Through a series of activities such as drawing, cutting, observing, imagining, classifying and finding the axis of symmetry, students can correctly understand the significance and characteristics of axisymmetric graphics.

2. Grasping the symmetry of the plane figure you have learned, you can find out its symmetry axis correctly.

3. Cultivate and develop students' experimental operation ability, discover beauty and create beauty.

Emphasis and difficulty in teaching

Grasping the symmetry of the plane figure you have learned, you can correctly find out its symmetry axis.

teaching tool

courseware

teaching process

First, the introduction of new courses:

(1) Enjoy the following graphs and find the symmetry axis of each graph.

(2) students communicate with each other.

What other axisymmetric figures have you seen?

(3) The concept of axisymmetric figure:

If a graph is folded in half along a straight line, the graphs on both sides can completely overlap, and this graph is an axisymmetric graph.

(4) Explore the properties of axisymmetric graphics through examples:

Example 1:

Students use a ruler to measure and calculate the distance between the opposite points on the left and right sides of each axisymmetric figure in the problem and the axis of symmetry. What patterns can you find?

Student exchange

Teacher:? In an axisymmetric figure, the distance between opposite points on both sides of the axis of symmetry is equal? We can use this property to judge whether a graph is symmetrical or not. Or make a symmetrical figure.

Second, practice in class.

1. Determine whether the following figures are symmetrical, and if so, please indicate their symmetrical axes.

Third, teach to draw symmetrical figures.

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 research, let students try to draw with pencils.

(3) Demonstrate the whole process of painting through courseware to help students correct their shortcomings.

Fourth, practice:

Classroom exercises 1- questions 1 and 2.

homework

Finish homework related to exercises after class.

Axisymmetric Teaching Plan (II) Teaching Objectives

1. Further understand the axial symmetry of graphics and explore the essential characteristics of forming axial symmetry.

2. Draw an axisymmetric figure on the grid paper, and initially learn to design the pattern on the grid paper with symmetry method.

3. In the process of appreciating the beauty created by graphic transformation, feel the application of symmetry in life and appreciate the value of mathematics.

Emphasis and difficulty in teaching

[Teaching Emphasis] Explore the characteristics of forming axisymmetric graphics and the methods of drawing axisymmetric graphics. [Teaching Difficulties] Explore the essential characteristics of axial symmetry in painting.

teaching process

First, create a situation to stimulate interest

1, enjoy axisymmetric graphics.

There are some beautiful figures in our life. Do you know what they are? (Play axisymmetric graphics)

Students observe and appreciate

Do you know where its symmetry axis is? What other axisymmetric figures have you seen?

(1). The meaning of axisymmetric graph;

(2). What are the characteristics of this graph?

3. Summary:

(1) If a graph is folded in half along a line, the graphs on both sides can completely overlap, and such a graph is an axisymmetric graph.

(2) The straight line where the crease is located is the axis of symmetry of the axisymmetric figure.

Which of the following figures is axisymmetric?

4, stimulate interest and lead to topics.

Look and say, which of the following figures is axisymmetric?

Should I draw such a beautiful figure? Shall we study together in this class? Axisymmetric? .

5. (The blackboard reveals the topic: axial symmetry)

Point out the axis of symmetry of the following axisymmetric figures. How many are there in each axisymmetric figure?

Design intention: Show all kinds of axisymmetric patterns and plane graphics through courseware, stimulate learning interest, review old knowledge, and pave the way for the study of new courses. By demonstrating the symmetry axis through animation and folding the graphics on both sides, we can initially feel that the characteristics of the symmetry axis are completely coincident along the left and right sides of the symmetry axis, and introduce a new lesson to explore.

Second, explore independently and master new knowledge.

1. Guess the courseware shows half of the axisymmetric figure. Let the students guess what this number is. Can you guess what the other half is? Why do you think so?

Design intention: to stimulate students' interest and guide them to learn independently.

2. Count?

Mark some points on the map. Do they have anything to do with the axis of symmetry? Take a look and see what you find. (the courseware shows a, a? 、B、B？ 、C、C？ )

Talk to the deskmate in the group first.

Reporting communication: a, points a and a? The distance to the symmetry axis is 2 squares, points B and B? The distance to the symmetry axis is three squares, point C and point C? The distance to the symmetry axis is 5 squares. B, a and a? The line is perpendicular to the axis of symmetry, point B and point B? Connect point c and point c? They are all perpendicular to the axis of symmetry.

Summary: A, points A, B and C are mathematically called the origin, and point A? 、B？ 、C？ Call it a corresponding point. B the distance from the origin to the corresponding point is equal to the axis of symmetry, and their connecting line is perpendicular to the axis of symmetry.

Draw a picture

Take out the square paper and draw a picture.

Summary method: first mark the origin, and then find the point corresponding to the origin. Then draw the connection.

Design intention: first, let students try to draw, then guide them to draw, and finally summarize the drawing methods and formal skills, so that students can experience axial symmetry in drawing.

4. Cut, cut, cut, do, work in groups, guess first, then cut, and see who cuts quickly and well.

Design intention: through operation, learning and deepening experience, we can further master the knowledge of axisymmetric graphics.

5. Summary: What knowledge did we learn just now by guessing, counting, drawing and cutting? Third, consolidate new knowledge and enhance knowledge.

1, which objects around you have axisymmetric figures?

Plane graphics (rectangle, square, equilateral triangle, isosceles triangle, isosceles trapezoid, circle, parallelogram, etc.). Ask the students to identify which are axisymmetric figures and find out the axis of symmetry. Focus on students' analysis of parallelogram and draw pictures to explain the reasons.

Design intention: deepen the understanding of axisymmetric plane graphics and understand the essential characteristics of axisymmetric graphics.

2. Can you draw the axis of symmetry of the following axisymmetric figure?

Take out a square piece of paper and design a beautiful pattern according to today's study.

Hands-on design

Show your work to everyone and tell us how you designed it. (Stick the students' works on the blackboard)

3. Judge: Which of the following figures is an axisymmetric figure? How many axes of symmetry do they have?

4. Judge: Which of the following letters is an axisymmetric figure? How many axes of symmetry do they have?

6. Happiness test:

7. Expansion problem

(1), reasoning: Draw the shape of the next figure according to the rules you find?

(2) Thinking: Observe and say the corresponding points A and A on both sides of the symmetry axis in the figure below. , b and b? Are the distances to the symmetry axis equal?

Design intention: to create and experience the beauty of mathematics by using axisymmetric knowledge.

Fourth, sum up, improve and extend feelings.

Axisymmetric graphics are everywhere in our daily life. If you are a serious and responsible person, you will find a lot. What have you learned from today's knowledge?

Design intention: Let students discover that mathematics originates from life, serves life, feels the beauty of mathematics and experiences the life of mathematics.

Five, homework design

Design a picture with axisymmetric knowledge entitled? Beautiful house? The work of.

Blackboard design: axisymmetric