Mathematics "Rotation of Figures" lesson plan for the fourth grade of primary school

# Lesson Plan # Introduction "The Rotation of Figures" belongs to the field of "space and graphics", and is the most primitive foundation in the field of space. This period of time for students is a sensitive period for children's spatial concepts. This kind of mathematics If the concept is well developed, the creative ability will be unlimited. Kaowang has prepared the following lesson plan, I hope it will be helpful to you!

Chapter 1

1. Create a scene and feel the rotation

1. Show 3 pictures: Fans, windmills, fireworks

Teacher: How do these objects move? Can you gesture?

Summary: We call a motion phenomenon like this rotation.

Teacher: There are many rotation phenomena in life. Can you give an example?

Teacher: In today’s class, we will study the rotation phenomenon of graphics together. (Unveiling the question)

Show the concept of rotation: In a plane, rotating a figure by an angle around a vertex in a certain direction is called rotation.

2. Understand clockwise and counterclockwise rotation

Show the picture of the rotating rod

Question:

(1) From this picture , what do you see?

(2) How do the rotating rods rotate? What are other similar examples of rotation in life?

(3) Understand the meaning of clockwise and counterclockwise rotation. What are the similarities in the rotation process when the rotary lever is opened and closed? What's the difference? Which one is the same as the direction in which the hour hand rotates?

Summary: The same direction as clockwise rotation is clockwise rotation, and the opposite direction is counterclockwise rotation. When the lever is opened, it is rotated 90° counterclockwise, and when it is closed, it is rotated 90° clockwise.

3. Understand the three elements of rotation

Show the grid diagram: Rotate the triangle ruler 90° around point A

Teacher: "Rotate around point A" What does it mean? Can this point be moved? Student self-practice

Teacher: What is the relationship between the edge after rotation and the edge before rotation? Can anyone tell me how to draw it?

Teacher: What do you think should be determined when rotating graphics?

Provide the three elements of rotation: rotation center, rotation direction, and rotation angle

4. Solve practical problems in life

1. Do "think about it, do it" "Question 1

(1) Observation and communication; students complete independently.

(2) Communication: From 6:00 to 9:00 and from 9:00 to 12:00, the hour hand rotates 90 degrees.

(3) If the items on the scale are removed, how does the pointer rotate? What about the pointer on the dial?

2. Question 2 of “Think About It”

Question: How do you draw?

***Same summary: To determine the position of the rectangle after rotation, the key is to determine the position of the two adjacent sides that intersect at point A; to determine the position of the small flag after rotation, the key is to determine the flagpole location.

3. Question 3 of "Think About It"

Question:

(1) Observe the two figures in each group, what do you find? ?

(2) Can you rotate one figure in each group so that each group of figures becomes a rectangle?

(3) How do you draw? Can the last shape only be rotated once? How many degrees did it rotate in one go?

5. Summary of the whole lesson

What did you gain from studying this lesson?

What should you pay attention to when rotating graphics at a certain angle?

Chapter 2

〖Teaching Content〗

"Transformation of Graphics" Pages 54-56 of the fourth unit of the fourth grade volume of Beijing Normal University Edition.

〖Textbook Analysis〗

Before learning this part, students have already experienced the translation and rotation phenomena in life in the third grade, and can draw them on graph paper A graphic that is translated horizontally and vertically.

The content of this lesson is an extension of the above-mentioned basis. It introduces students' perspective to the rotation of graphics. It is intended to enable students to experience the process of turning simple graphics into complex patterns through a series of activities such as appreciation, exploration, and creation, and understand The center point, direction, and angle of rotation are different, and the patterns formed are also different, which further develops students' spatial concepts and lays the foundation for continuing to learn graphic transformation in the future.

1. During the operation, let students experience the characteristics of graphic transformation

In the teaching of this unit, students should be encouraged to operate by hand and think actively during the operation. . For example, the "Rotation of Figures" activity (page 54 of the textbook), the two beautiful patterns displayed in the textbook are obtained by rotating a simple figure. During teaching, you can prepare four pieces of paper with the same pattern on them, and then rotate them one by one around a certain point. After rotating 90°, stick one piece of paper on it, then rotate 90° again, and stick another piece of paper until a complete pattern. During the rotation process, teachers should remind students to observe and think about: what changes have occurred in the pattern and which point it rotates around.

Many of the exercises in this unit are operable. Therefore, students can be asked to prepare some small learning tools before class, so that students have the opportunity to operate during the teaching process. Some questions in the exercises are also answered through students' operations to improve students' perceptual understanding.

2. In the transformation of graphics, different operating methods are advocated

After a graphics is transformed, a new graphics can be obtained, but the same new graphics can be obtained in different ways. method of operation. Therefore, you can let students think about it first, try it on graph paper, and then talk about it as a class. During the teaching process, teachers should go deep into students' activities, discover students' distinctive operating methods, and provide encouragement and affirmation to provide conditions for students to learn and communicate with each other.

3. In the process of appreciation, encourage students to design and make beautiful patterns

The mathematical appreciation content of this unit is any simple figure, when it rotates around a point, and Draw the shape after each rotation along the outline, and a beautiful pattern will be formed. In third grade, students have already appreciated the process of rotating squares and made them. This unit further expands this content to any simple graphics. During the teaching, students are first asked to appreciate it, and then each student cuts an arbitrary simple figure out of cardboard, and then transforms it into production. Teachers should affirm the patterns made by students as long as they basically meet the requirements. For some students with particularly excellent designs, they can also be asked to demonstrate it again on the spot to motivate students with weaker hands-on abilities.

〖Teaching Objectives〗

1. Further understand the rotation transformation of graphics and explore its characteristics and properties.

2． Ability to rotate simple shapes 90 degrees on graph paper. .

3． Initially learn to use the rotation method to design patterns on graph paper and develop students' spatial concepts.

4． Appreciate the beauty created by the rotation and transformation of graphics and cultivate students' aesthetic ability; feel the application of rotation in life and appreciate the value of mathematics.

〖Teaching Focus〗

1. Understand the meaning of graphics rotation transformation.

2． Explore the characteristics and properties of graphical rotation.

　〖Teaching Difficulties〗

　1. Explore the characteristics and properties of graphic rotation.

2. Be able to rotate a simple figure 90° clockwise around a fixed point on graph paper and describe the rotation process.

　〖Teaching Tools〗

Multimedia courseware, one learning tool bag (basic graphics, colored pens) for each table.

〖Teaching Process〗

1. Scenario introduction:

This is a windmill that children like to play with.

Invite two children to play with the teacher. (Study operation)

Other children, please pay attention to how the windmill moves?

Who can tell me what you see in the movement of the windmill?

(Solve rotation, center of rotation, direction of rotation)

Show the clock face

In mathematics, I call the direction of rotation in this direction clockwise. ;

Counterclockwise.

Gestures, gestures.

Summary: In the mode of motion just now, we can say,

The windmill rotates clockwise around the center point;

Or the windmill rotates counterclockwise around the center point direction of rotation.

Can you speak?

2. New teaching:

In life, there are various beautiful patterns, some of which are simple graphics obtained by translation and rotation.

Do you want to know how these patterns are designed? (Want to know?)

Then today we will further study the "rotation of graphics". (Blackboard writing topic)

Then let’s choose a simple pattern and study from easy to difficult what kind of simple shapes it is made of and how it is rotated. Please observe carefully.

Courseware display

In order to facilitate research, the teacher also specially made a model like this and pasted it on the blackboard.

Discussion:

Talk to each other in the group, what did you see just now?

(The shape and size remain unchanged)

Teacher: How to transform from figure A to figure B?

How to rotate. (Clockwise around point O...)

How many degrees has it been rotated?

How do you judge that it has rotated 90°?

(If there is any method, think about it and talk to each other)

Combined with the legend, draw the corresponding sides in the picture and mark the rotation angle. Measurement.

This degree is called the degree of rotation

In summary, Figure B can be seen as Figure A rotated 90° clockwise around point O

Who can give a complete explanation? Again.

Emphasis on three elements.

Teacher: How to transform from graphic B to graphic C?

What about graph A to graph C?

Students, we can say that figure A is rotated 180° clockwise around point O to obtain figure C; are there any other explanations? (With gestures)

Counterclockwise

Seeing this picture, what else can you say like this?

Teacher summary, only when the center of rotation, direction of rotation and degree of rotation are determined, the position after rotation can be determined.

3. Consolidation exercises:

1. Turn around. (Hands-on operation)

Tell me about the point around which these triangles rotate.

2.

4. Appreciate and sublimate.

Feel the beauty of rotation and mathematics.

What simple shape is it made of?

Part 3

Teaching Objectives

1. Through observation of examples, understand the process of rotating a simple figure to create a complex figure.

2. Ability to rotate simple graphics 90° on graph paper.

Important and difficult points in teaching: being able to rotate simple graphics 90° on graph paper.

Activity process:

Activity 1: Create scenarios and solve problems

(1) In life, there are various beautiful patterns, but there are many of them Patterns are obtained by translation or rotation of simple graphics. This activity introduces the process of rotating simple shapes to form complex patterns.

(2) In the introduction stage of the activity, a set of patterns can be presented for students to appreciate. Then these patterns are decomposed into certain shapes, and a small part of them is taken out and placed on the square grid for rotation, and the process of rotating simple graphics to form complex patterns is gradually demonstrated. Of course, every time there is a rotation, students are asked to talk about what figure rotates around which point? What is the angle of rotation? Students can also use learning tools to operate it themselves, so that students can experience the process of rotation.

Activity 2: Practical exercises

On the basis of students completing independently, the whole class will communicate and the teacher will provide guidance.

Question 1

The exercise of this question mainly focuses on understanding the point around which the rotation of the figure rotates. Therefore, this activity can be done independently by students first, and then the center of rotation can be discussed point question.

During the activity, each student can prepare some white paper and triangles. In order to allow students to experience the changes in graphics before and after rotation, students can first draw the triangle on their hands along the sides of the triangle, then rotate around one vertex of the triangle (the angle of rotation can be arbitrary), and finally say Let’s talk about the point around which this triangle rotates.

Question 2

Similarly, for this question, students can also be asked to perform rotation operations according to the requirements and draw the graphics obtained during each rotation. Then discuss the angles of rotation from figure 1 to figure 2, from figure 2 to figure 4, etc.

Mathematical Kaleidoscope

Schools with conditions can use multimedia to demonstrate the rotation process of this question. If students are interested, they can also let them cut an arbitrary triangle and then rotate it while tracing the resulting shape, so that every student can create a beautiful pattern.

Question 2

During practice, students can first use triangles to operate on the square grid as required. After students become more proficient, ask them to draw rotations as required. graphics.

Question 3

Similarly, for the exercise of this question, students are also asked to place it themselves. During the process, let students accumulate some experience and then color it.