Knowledge teaching school

1. Skillfully use the thinking strategy of analysis and summary to guide students to intuitively understand symmetry in activities such as observing physical objects, analyzing and comparing, and hands-on operation. Learn to appreciate the beauty of mathematics.

2. Guide students to know the symmetry between objects and pictures, master the basic methods to judge whether pictures are symmetrical, and promote the development of students' spatial concept.

Ability teaching points cultivate students' observation and hands-on operation ability. Through effective mathematical activities, students can form a preliminary concept of space.

Moral education teaching points realize the close relationship between symmetry and life.

Teaching focus:

Master the basic method of judging whether the picture is symmetrical or not.

Teaching difficulties:

Understand the symmetry of the object and the picture, and understand that the edges are completely coincident.

Teaching preparation:

Courseware, square, triangle, circle and other graphic pieces of paper, schoolbags

Teaching process:

First, appreciate symmetry and stimulate the introduction of interest.

Teacher: Let's play a game together. Please guess who is in the photo?

Show the courseware, show the photos of the students who are familiar with this course, and only show half of the photos for everyone to guess.

Q: How did you guess? (Student answers)

Teacher: In this process, we used a mathematical knowledge called "symmetry", so we can guess it soon. Let's learn symmetry together in this lesson.

(blackboard writing: symmetry)

Second, understanding symmetry and establishing concepts

Show three pictures that students are familiar with: Diabolo plane big head doll (marked with symmetry axis)

Q: Please look at these three figures. What did you find? (Diabolo is the same from top to bottom) (The left and right sides of the plane are the same) (The face of the big-headed doll is the same from the left and right sides)

Induction: An object like this, with the same sides, is said to be symmetrical.

Third, understand symmetry and sensory characteristics.

1. Take a look: Show me the pine tree map and the Audi logo, and ask: Is it symmetrical? Students judge and tell the reasons, demonstrate the folding process of pine tree and Audi logo, and understand the meaning of complete coincidence of edges. If the two parts are folded in half like a pine tree and an Audi logo, and the edges can completely overlap, then we say that this picture is symmetrical.

2, fold a fold: (showing triangles, squares) Q: Is the square symmetrical? How did you know? How did you fold it? Is the deskmate AC triangle symmetrical? State your reasons.

3. Talk about it: show thinking strategies and thinking skills. Group communication: Is it a good way to verify whether a figure is symmetrical by using clever and generalized thinking strategies?

Classroom communication

Summary: the method of judging symmetry

(1) Fold in half or draw a dotted line.

(2) Same shape and size

(3) The edges are completely coincident

4. Look for it: symmetry can be seen everywhere in life. Then let's find it together! Let's see if there is symmetry in common numbers.

Display numbers: 2, 9, 3, 5, 0, 8.

5. Guess: Our Chinese class is also symmetrical.

Display Chinese characters: Western, Chu, Wang, Jin and Tian.

Guess which words are symmetrical. There is also symmetry in English class.

Show English letters: C D E M T F

See which letters are symmetrical.

6. Reward: What else have you seen in your life that is symmetrical?

Let the students talk about many symmetrical phenomena in life. Let's appreciate the symmetrical beauty in life.

(Show courseware) Dragonflies, butterflies, paper-cuts, Peking Opera masks.

Buildings: Temple of Heaven, Tiananmen Square, Arc de Triomphe

Dance: avalokitesvara with a thousand hands

Third, consolidate practice and make correct judgments.

1, the students all know symmetry, so can you judge which of the following figures are symmetrical and which are not?

2. Observe this car. From which direction does it look symmetrical? From which direction does this car look asymmetrical?

3. Show the jigsaw puzzle and tell whether these spelled figures are symmetrical. Show the jigsaw puzzle and see which patterns are symmetrical. Cultivate students' ability to examine questions

4. Put a pendulum, cut it, draw a picture and do it: After learning symmetry, I want you to use what you have learned to exert your creativity and make some symmetrical objects to decorate our classroom. You can cut out a symmetrical picture with scissors, or you can spell out a symmetrical picture with a puzzle, or you can draw a symmetrical picture. Appreciate students' works

Four. abstract

What did you learn from this course?

Blackboard design:

Thinking strategy: analysis is more ingenious and inductive.

Thinking tip: find similarities, differences and summarize characteristics.