Lecture notes on axisymmetric graphics of People's Education Press
First of all, talk about textbooks.
"Axisymmetric Graphics" is the teaching content of Unit 7, Book 3, Primary Mathematics, Jiangsu Education Press. This lesson is based on students' understanding of simple plane graphics. The textbook starts with things that students are familiar with, and through various activities, students can initially perceive the symmetry phenomenon in life, and then know the simple axisymmetric figures and axes of symmetry, which will lay a good foundation for students to further explore the axisymmetric characteristics of simple figures and master the axisymmetric relationship between simple figures in the future. The textbook first asks students to observe and analyze their similarities and differences through Tiananmen Square, airplanes, trophies and other physical pictures. Symmetry? The concept of. Next, the textbook abstracts these objects into plane graphics, guides students to find the basic characteristics of axisymmetric graphics by folding them in half, and initially describes the concept of axisymmetric graphics.
Second, the teaching objectives:
1. Cognitive goal: Through observation and hands-on operation, let students initially experience the symmetry phenomenon in life; Understanding some basic characteristics of axisymmetric graphics is helpful for us to understand axisymmetric graphics and axis of symmetry.
2. Ability goal: to cultivate students' ability of independent inquiry, observation, comparison and generalization, as well as the consciousness of group cooperation.
3. Emotional goal: let students feel the symmetrical beauty of objects or figures in the process of understanding, making and appreciating axisymmetric figures, and stimulate positive feelings for mathematics learning.
Teaching emphasis: understanding the characteristics of axisymmetric graphics.
Teaching difficulty: master the method of identifying axisymmetric figures.
Third, oral teaching methods
The new curriculum standard points out that there is no fixed method in teaching, and it is important to have correct methods. I pay attention to enriching students' feelings and cognition of shapes, connecting with real life, creating problem situations, and organizing students to carry out exploratory learning activities by means of intuitive demonstration, doubt induction and operation discovery, so that they can learn new knowledge, experience exploration and acquire knowledge through independent exploration.
Fourth, the methods of speaking and learning
Effective mathematics learning activities are not simply dependent on imitation and memory, but a purposeful and positive process of knowledge construction. To this end, I attach great importance to the guidance of students' learning methods. In this class, the methods I use to guide students to learn are: hands-on operation, independent inquiry, observation and discovery, and cooperation and exchange. Let them perceive symmetrical features in a series of activities such as folding, discussing, talking and cutting.
On the Teaching Process
(A), create a situation, the introduction of new courses
Courseware shows pictures of Tiananmen Square, airplanes and trophies (pay attention to the symmetry from different angles), guides students to observe and summarize the similarities and differences of these objects, and then abstracts these objects into plane graphics through multimedia demonstrations. Finally, demonstrate the folding of these graphics with courseware, and let students observe the left and right or up and down of these three pictures. What are their shapes and sizes? Through observation, it is estimated that students can find that the left and right sides or the top and bottom of the figure are the same shape and size, which naturally leads to the topic.
(B), independent inquiry, feeling new knowledge
1, 10% discount
Let the students take out the three figures of Tiananmen Square, airplane and trophy prepared before class, fold them in half, and guide the observation and discovery.
Step 2 talk about it
After the homework, according to the students' statements, guide the students to communicate, seize the opportunity and guide their understanding? Fold in half? 、? Coincidence 、? Crease? Key words, etc., to guide students to distinguish by comparative method? Coincidence With what? Completely coincident? The difference between them helps students to summarize in time and guide them to get the concept of axisymmetric graphics and understand the axis of symmetry.
3. distinguish.
Combination? Try it? Ask the students to identify axisymmetric figures from some simple plane figures they have learned. Guide students to judge, verify and explain the reasons, right? Triangle? And then what? Parallelogram? Are all axisymmetric figures. Discuss and analyze, combine right triangle and diamond, and let the students clearly aim at it. This triangle? Or? This parallelogram? Distinguish and experience the rigor of mathematics and? Specific analysis of specific problems? The initial idea.
4. Do it. (Create an Axisymmetric Graph)
In the way of group cooperation, let students make axisymmetric figures by hand, and further realize that the two sides of the axis of symmetry of axisymmetric figures can overlap completely through making. Students have a variety of production methods, such as painting, cutting, enclosing and spelling. Although the production methods are different, the principle is the same, and they are all making completely coincident figures on both sides of the symmetry axis. Here, I guide students to experience while doing, and tell each other how to do, how to think, and why to say that the graphics are axisymmetric, so as to achieve the purpose of making.
(3) Consolidate practice and strengthen new knowledge.
Practice is an important link in mastering knowledge, forming skills and developing intelligence. According to students' age characteristics and cognitive rules, in line with the principles of fun, thinking and comprehensiveness, from easy to difficult, from shallow to deep, we strive to reflect the vertical and horizontal connection of knowledge, so as to achieve uniform form and clear hierarchy. I designed the following groups of exercises.
1, basic exercise:? Look for it? . ? Thinking about doing it? Question 1, 2, 5, 6.
Design concept: let students further consolidate their understanding of axisymmetric graphics and accurately judge whether a graphic is axisymmetric.
2. expand your business? Draw a picture and guess, even for a moment? . ? Thinking about doing it? Questions 3 and 4.
(4) class summary
At the end of the class, let the students talk about their own gains and experiences, and summarize them in the way of students' self-review, so as to promote students' internalization of knowledge, cultivate students' ability to organize their own knowledge, and devote themselves to the next class with greater enthusiasm.
(5) Appreciate pictures and experience emotions.
Courseware playing: symmetry in life.
Design concept: on the one hand, let students feel the beauty of symmetry, on the other hand, let students realize that mathematics comes from life and is applied to life.
Shuobanshu design
axial symmetric figure
Completely coincident axisymmetric figure
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Folding symmetry axis
Design concept: blackboard writing design strives to embody knowledge and simplicity, so that students can see it at a glance.
Teaching reflection
In the teaching of axisymmetric graphics, I can fully understand the teaching materials and boldly explore and create teaching materials. In the teaching process, we can give full play to the leading role of teachers and the main role of students according to students' cognitive laws, create problem situations and stimulate students' desire for learning. Take? Give me a discount, spell, divide, say? And other practical activities, so that students can fully experience the formation process of knowledge, feel the fun of learning mathematics, and cultivate students' ability of observation, communication and operation.
First, the new teaching is novel and pays attention to students' hands-on operation.
In the newly taught part, by showing the graphics of Tiananmen Square, airplanes and trophies, let students find the symmetry axis by folding in half, and make an axisymmetric graphic by themselves, so that students can master the characteristics of axisymmetric graphics in hands-on operation and find out the key words: folding in half and completely overlapping. Let the students remember deeply.
Second, give students the space to develop independently and cultivate their ability to learn mathematics.
The new curriculum advocates students' active participation, exploration, communication, cooperation and other learning activities, so that students can truly become the masters of learning. In this class, I gave students the right to learn, from the initial perception to further understanding, and then to students using their own experience to create all kinds of axisymmetric graphics. In the whole teaching process, students are provided with a space to fully engage in mathematical activities and exchanges, so that students can develop harmoniously in this space and truly cultivate their ability to learn mathematics.
Third, create a situation for students to enjoy learning, pay attention to the development of students' personality and cultivate aesthetic taste.
The process of learning mathematics should be positive, enjoyable and imaginative. This lesson goes from introduction to new teaching to practical operation. Do students do it? Do what? Axisymmetric graphics give students an opportunity to show their personality, so that students can acquire mathematical knowledge, be influenced by beauty and cultivate positive and healthy aesthetic taste.
Issues worthy of discussion:
1. As far as the characteristics of the textbook are concerned, it is easy to make the lesson lively and interesting, but this lesson is a bit lacking, that is, the key knowledge of this lesson is not emphasized enough (completely overlapping after being folded in half).