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Lecture Notes on "Angle Measurement" (3 selected articles)
Lecture Notes on "Angle Measurement" (3 selected articles)

As a conscientious people's teacher, it is often necessary to write lectures, which are the manuscripts for preparing lectures and play a vital role. How to concentrate the lecture notes? The following is the speech of "Angle Measurement" that I compiled for you. Welcome to share.

First of all, talk about textbooks.

I said that the content of the class is the first lesson of Unit 2 "Angle Measurement" in the first volume of the fourth grade mathematics of People's Education Press. The main content of the textbook is to learn the measurement method of angle, which can measure the angle correctly. In the teaching process, I always adhere to the concept of the new curriculum standard, guide students to actively participate in the learning process, take the discovery and development of students' thinking as the goal, take students' curiosity as the starting point, stimulate students' interest, and maximize the time and space for students to explore independently through the process of questioning and solving doubts, tap students' learning potential, and cultivate students' ability to think independently and actively acquire and apply knowledge. In addition, through a series of diverse exercises, classroom teaching is diversified and interesting, and classroom teaching is full of vitality.

According to the teaching content of this class and the students' reality, I set the following teaching objectives:

1, through students' independent observation and understanding of the protractor, knowing the measurement unit of the angle, they will find different angles on the protractor and know its degree.

2, through independent exploration and cooperative learning, learn to use the protractor to measure the angle correctly, and read the degree.

3. Through a series of observation and calculation activities, we know that the angle is related to the size of the fork on both sides, and has nothing to do with the length of both sides.

4, through group cooperative learning, cultivate students' practical ability and the ability to actively participate in learning and dare to explore.

The teaching focus of this lesson is to know the protractor and use it correctly.

The difficulties in teaching are: using protractor to measure the angle correctly and reading the degree of the angle correctly.

Second, say the learning situation:

Mathematics learning activities must be based on students' cognitive development level and existing life experience. Students' understanding of the angle has been explored and has a certain foundation. This lesson takes students' curiosity as a breakthrough to stimulate students' interest. Through the process of questioning and solving doubts, students are given the maximum time and space to explore independently. Through group cooperation, students can operate the measurement method of inquiry angle and cultivate their ability to solve problems independently. Encourage students to express their opinions boldly and strive to create a democratic, equal and harmonious classroom atmosphere.

Third, teaching methods and learning methods:

The new curriculum standard puts forward that what students can explore by themselves will never be replaced; Whatever students can think independently, they will never hint. This course creates certain problem scenarios according to students' age characteristics and knowledge level, so that students can find problems, analyze problems and find solutions, which can inspire students' flexibility of thinking, cultivate students' profundity of thinking and stimulate students' innovative consciousness. Try to show that students are the masters of learning and teachers are the organizers, guides and collaborators of teaching.

According to the teaching content and teaching objectives of this course, I will design four links to break through the teaching objectives:

1, showing stick figures to stimulate interest;

2. Cooperation and exchange, observation and research;

3. Try to measure the angle and explore the method of measuring the angle;

4, fun exercises, expansion and extension;

5. Small conclusion

(1) Show stick figures to stimulate interest.

Show the stick figures and ask: What do you find from these two stick figures? Through observation, the students found that the figure is composed of line segments, circles and angles, so the teacher asked: What do you know about the diagonal? Simple questions urge students to recall what they have learned and summarize it in their own language, which prepares them for learning new knowledge, and also provides students with weak ability with opportunities to answer questions, thus stimulating their desire to learn. In this link, according to the characteristics that primary school students like stick figures, simple and vivid stick figures can stimulate students' interest in learning and arouse their enthusiasm, which can better mobilize their learning motivation and smoothly guide them into the new curriculum.

(2) Cooperation and communication, observation and research (observation room)

The whole process runs through a visit to "Graphic Research Institute" and puts forward the research content-how to measure the angle. In this section, we mainly visit the "observation room"-knowing the protractor. First, show the protractor and let the students observe the composition of the protractor. The teacher asked: Now observe the time freely and carefully observe what is on the protractor. Teamwork, who found more? Through students' group cooperation and exploration, we can express our findings in the form of groups, cultivate students' observation ability and expression ability, and let students fully appreciate the fun of success. In "comparison", students' various learning motivations are activated, and cognition and emotion develop simultaneously. Students know the structure and measurement unit of protractor, and observe the angle of 1 degree, observe the scale of protractor, and focus on the inner ring and outer ring. Through intuitive demonstration, students can form the appearance of1angle on the basis of perception, which is also in line with the law of students' cognition; Then let the students start looking for some special angles on the protractor. Here, the teacher raised an inquiry question: there are two scales 30 and 150 on the protractor. Which one do you think should be read correctly and why? According to the knowledge that students have mastered: acute angle is less than 90 and obtuse angle is greater than 90, which is beneficial to cultivate the profundity of students' thinking and make these special angles form images in students' minds. Then, students can find the scale line and read out the degrees of different sizes, thus breaking through the difficulty that the scale of the inner and outer rings is easy to read wrong and making full preparations for the following links.

(3) Try to measure the angle and explore the method of measuring the angle (operating room)

At the beginning of this class, the teacher suggested: Try to measure and think while measuring. How do you measure? Is there any good way? Students answer questions and measure angles themselves, and discuss with their classmates how to measure angles; At the beginning of students' introduction, teachers should guide students to use mathematical language strictly and correct it in time. In view of these difficulties, teachers should design:

1, the edge of the protractor is aligned with the edge of the corner, right? What should I do?

2. When looking at the degree, there are two figures. What should I think? When to look at the inner ring and when to look at the outer ring?

Two questions, guiding students to sum up knowledge, contribute to the accumulation and deepening of knowledge and are important means to develop students' memory and thinking ability. Finally, the teacher summed up the "research method" on the basis of students, and reproduced the process of angle measurement, which not only enabled students to deepen the consolidation of knowledge, but also helped to solve doubts for some students with learning difficulties.

In the whole process, students independently bring questions and explore problems through group cooperation, which embodies the student-oriented, allows students to fully express their opinions, truly embodies everyone's participation and everyone is the master of learning, and once again cultivates students' sense of cooperation.

(c) Fun exercise, extension and extension-research report

Practice is a necessary means for students to master knowledge, develop intelligence and cultivate ability. I designed the following three levels of exercises in this class:

(1) Measure and queue.

Use a protractor to measure the degree of each angle below, and arrange these angles in your favorite way, which can not only consolidate the key content of this lesson, but also understand the new knowledge of students in time.

(2) Measure and place a picture.

Measure the degree of each angle of the triangle, and set it as 75, 120, 135, 180.

(3) cutting and measuring

Cut a pentagram and measure the degree of each corner of the pentagram in groups.

In the whole exercise, students can mobilize their senses through a series of activities such as comparing angles, spelling angles, finding angles and measuring angles. Encourage students to imagine boldly, use new knowledge to create a space for students to fully disperse their thinking, guide students to discover and create, and cultivate students' initial innovation consciousness and ability. Lively and interesting games can not only arouse students' enthusiasm for learning, but also let them experience the application process of mathematical knowledge.

(4) Small conclusion

First, let the students talk about themselves. What have you learned through today's study? Students can not only know their mastery, but also cultivate their generalization ability by summarizing and sorting out what they have learned. Teachers give timely evaluation, so that students can experience success and enhance their learning confidence. Assigning open homework can fully stimulate students' interest in learning.

Dear judges:

Hello! The topic of my speech today is: the experimental textbook of compulsory education curriculum standard People's Education Press, the first volume of fourth grade primary school mathematics, Unit 2 Angle measurement, in the second class. Now I will talk about it from the following aspects.

First, grasp the curriculum standards, teaching materials

(A), the status of teaching materials

The second lesson of "Angle Measurement" is the content of unit 2, page 37-39 in the first volume of grade four. This textbook has three stages, and the angle measurement has two levels. The first level is to introduce protractor and angle measurement method. The second level, let students make it clear that "the size of the angle depends on the size of both sides, and has nothing to do with the length of the drawn side." This concept is not only to enable students to acquire knowledge about graphics, but more importantly, to cultivate students' spatial concepts and skills in operation and drawing.

(B), teaching objectives

Considering the content of the textbook comprehensively, starting from the students' reality and according to the spirit and requirements of the Mathematics Curriculum Standard, the following learning objectives are formulated, and the key points and difficulties are determined.

1, knowledge and ability goal: let students know the protractor, measure the degree of angle with the protractor, and cultivate students' self-study, observation, practical ability and cooperative spirit through hands-on operation, independent inquiry and cooperative communication.

Process and Method Objective: To know the angle of 1 degree and the method of comparing angles.

Emotional attitude and values goal: through learning and operation, students can have a sense of accomplishment, stimulate their interest in learning mathematics, and make them want to learn, know how to learn and enjoy learning.

2. Teaching emphasis and difficulty: The protractor can correctly measure the degree of angle.

Second, play a leading role in teaching methods

"The power of teaching lies in guiding the way, and the beauty lies in enlightenment." Modern teaching theory holds that students' learning is not a process of passive acceptance, but a process of active construction. On the basis of understanding, I tried to make a breakthrough in the structure of this class, changing the situation that teachers ask, students answer, teachers talk, students listen and students passively accept learning. Therefore, the teaching mode of "moving people with emotion, attracting people with environment, cooperative exploration and independent innovation" has been adopted, and visual teaching AIDS have been used to create "situations" to strengthen "cooperation" and increase "playing games" to stimulate students' learning interest and thinking ability. Let students deeply understand the concept of angle measurement method and comparative angle size in the happy and relaxed learning process.

Third, determine the subjects and methods of speaking and learning.

Therefore, I organically link classroom teaching with students' participation, cooperation, thinking and emotional state. By creating interesting situations, students are curious and kind. When understanding protractor and angle measurement unit, students should think independently, cooperate at the same table, communicate with the whole class and cooperate collectively. When exploring the method of measuring angles with protractor, students in the group actively acquire knowledge through hands, brains and mouths, thus cultivating students' team spirit, autonomous learning ability, hands-on ability and innovative consciousness.

Fourth, reasonable arrangements and procedures.

Because this is the second class, students have a general understanding of the concept of diagonal. )

(a), the creation of the scene, * * * import

1, teacher-student interaction, deepening consolidation (the teacher wears a mask to play the king of the forest "Tiger Brother"). )

Emoko: "Please look at the big blackboard. This is a key point. What line leads from a point? " ? Just set up a ... ""What is this angle? These two rays are ...? "

2. Attract people with the environment and initially perceive them.

Introduction: "Students, look, what are the dove of peace and the ugly duckling doing?" Show the intuitive picture of the debate between the dove of peace and the ugly duckling. )

Teacher: What are they arguing about? They heard that our classmates were excellent at math, so they begged our classmates to help them solve this problem. In students' discussion and inquiry, let students find a tool to solve problems-protractor. At this time, according to the students' thinking motivation, we will promote a new learning content-angle measurement.

(B), independent inquiry, cooperative learning

Establish the concept of "1".

On the basis of consolidating and establishing the concept, I adopted the guiding question method: "What unit do we use to measure the length of the line segment?" "What unit is used to measure the size of an area?" Following the students' thinking, I asked the students what is the unit for measuring angles? I ask students to find answers from books and let them read by themselves. When the students know a thing or two, I ask them, "What have you learned by reading? What did you find? What difficulties have you encountered? The groups communicate with each other. " After students study independently, I send representatives to report the group results in groups. According to the students' answers, write on the blackboard in time: 1 degree is 1 degree. On the basis of students' preliminary understanding, I put the concept in the book: divide the semicircle into 180 equal parts, and the diagonal size of each equal part is 1 degree. So what's it like in 1?

(3) Think about the plot and define the task.

Through the interaction between students and teachers, I brought out a brand-new thing-protractor, which is much more complicated in shape, composition and connotation than the ruler commonly used by students before, but it is also a tool that must be mastered and used flexibly. So this year I adopted the form of letting students observe, think independently, communicate at the same table and cooperate with the whole class. I asked the students to take out the protractor and observe it carefully. What's on the protractor? On the basis of students' observation, I asked, "Who has the brightest eyes? Tell me what you see. " ? According to the students' answers, guide the students to know the names of each part of the protractor in time: outer circle scale, inner circle scale, center point and zero scale line. After the students got to know the protractor, I said, "Divide a semicircle into 180 equal parts, and the angle of one equal part is 1, and the angles of the two equal parts are ...? Three copies? How about four? ..... "With me, I will let my classmates learn knowledge and solve the difficulties encountered by doves and ugly ducklings. (Note: It is the degree of ∠ 1 and ∠2 measured on page 37 of the textbook. ) In the process of solving problems, I instruct students to summarize the methods of measuring angles, so that they can know when to look at the "protractor outer ring engraving" and when to look at the "protractor inner ring engraving".

At this point, I guide students to master the steps of measuring angles:

1. What should I do first after putting the protractor on the corner?

2. What should I do in the second step?

3. What about the third step?

4. How to judge whether to look at the outer ring engraving or the inner ring engraving? The exploration process allows students to understand independently, and at the same time, I have compiled an angle measuring formula: center to vertex, zero line to one side, and scale on the other side to distinguish between inside and outside. On the basis of students' independent completion, I boldly let students learn the concept of "comparative angle size" independently. From intuition to demonstration, from excessive knowledge, from questioning to daring to let go, the purpose is to let teachers and students operate together and let students fully understand the size of the comparative angle from a dynamic point of view: the size of the angle has nothing to do with the length of the paintings on both sides of the angle, but is related to the size of the angle.

(4), self-study supervision, to carry out the game

1, students' autonomous learning is also one of the requirements of the new curriculum. I let them feel the "angle" in life, and let them measure the angle of the national flag, the angle of the book, the angle formed by the hour hand and the minute hand on the clock face, and the angle of the triangle. After that, I let students feel the joy of game teaching and let them acquire knowledge in a relaxed atmosphere. I asked the students to wear animal headdresses. Each animal holds a protractor in its left hand and a stick in its right. In which part of the protractor, he pointed with the pen tip to see who could point accurately and quickly.

(5) Ask questions, reflect and exchange feelings.

Teacher: What did you learn through this class? What are your gains and feelings? How do you evaluate this class?

5. Face to face and write on the blackboard

Center to vertex, zero line to one side, the other side to see the scale, distinguish between inside and outside.

The size of the angle has nothing to do with the length drawn on both sides of the angle, but with the size of the angle fork.

textbook

I'm talking about the lesson of "Angle Measurement" in Unit 2 "Straight Line and Angle" in Grade Four Primary School of Beijing Normal University. The main contents of this unit are: understanding of line segments, straight lines and rays, understanding of straight lines and rounded corners, measuring and drawing angles with protractor. This part of knowledge is the basis for students to learn the classification of drawing angles in the future. The textbook focuses on strengthening students' operation activities, guiding students to understand the necessity of measuring angles with protractor, understanding the characteristics of protractor as an angle measuring tool, and understanding and summarizing the methods of measuring angles with protractor in independent exploration.

Say students

Students have a preliminary experience of diagonal knowledge and know that the size of the angle is related to the size of both sides. Some students have a preliminary understanding of protractor, but most students have little experience in measuring angles with protractor. Although the students have a small protractor in their hands, they are not familiar with it. Radial lines and different scales will make students unable to find the angle on the protractor, and how to measure the angle with the protractor is even more difficult. Moreover, in practice, it seems unnecessary for students to measure angles. What they have mastered is completely abstract mathematical knowledge, which can rarely be applied to life.

According to the understanding of the textbook and the students' reality, I set the goal of this class:

Knowledge goal: to know the protractor and the measurement unit of angle; You can measure angles with a protractor.

Ability goal: to cultivate and develop students' operational ability and thinking ability in angle measurement activities.

Emotional goals:

1. Encourage students to try boldly and express actively in the activities, so that students can be brave in exploration and innovation.

2. Apply what you have learned, explain the phenomena in life, let students feel the value of mathematics and cultivate their sense of application.

Teaching emphasis: know the protractor and measure the angle with the protractor.

Teaching difficulty: gradually experience and summarize the method of angle measurement in independent exploration.

Oral English teaching methods and learning methods

The main content of this lesson is measuring angle, which is a kind of learning of knowledge and skills. In the past, teachers explained the demonstration, students imitated the operation, and then carried out a lot of exercises to consolidate this skill. Undoubtedly, this method is inefficient for developing students' thinking ability. The new curriculum standard advocates that effective mathematics learning activities can't just rely on imitation and memory. Hands-on practice, independent exploration and cooperative communication are important ways for students to learn mathematics. Moreover, Mr. Tao Xingzhi said: "Teacher Wang's responsibility is not to teach, but to teach, but to teach students to learn." "Learn to do things and teach learning; The method of teaching should be based on the method of learning and the method of learning should be based on the method of doing. " Therefore, in this class, I try to make myself the organizer, guide and collaborator of students' learning, return the class to students, let students experience the significance and methods of measuring angles in independent exploration and cooperation, form a sense of measurement and develop students' spatial concept.

On the Teaching Process

In this process, I mainly designed a kite-flying competition, how to judge whose kite flies high and stimulate students' interest in inquiry, and then began to learn new knowledge, and then designed several activities suitable for students to actively participate in, that is, finding and measuring angles, so that students can understand the significance of measuring angles, explore and summarize the methods of measuring angles, and gradually master the skills of measuring angles. Finally, in the study of related phenomena in life, we can understand the role of angle in life, cultivate students' application consciousness and establish confidence in learning mathematics well. Let me say it alone.

First, create situations and introduce new lessons.

First, talk to the students. Do you like kites? Let go? Have you ever participated in a competition?

In this way, arouse students' life experience and stimulate their enthusiasm for learning.

The teacher brought pictures of small animals flying kites to the students. Look, how seriously they take them! It's time for the game, which makes the little monkey who just became a referee a little anxious. He only remembers that the rules of the competition are as long as the rope, and he forgets how to know who flies the kite high. What shall we do? Can you help this little monkey?

Guide the students to make it clear in the communication that if you want to know whose kite flies high, you only need to know the angle between the rope and the ground. The bigger the angle, the higher the kite flies. The angle between the rope and the ground is abstracted with multimedia courseware to help students understand the mathematics in life and form the ability of abstract thinking.

This problem situation can stimulate students' interest in inquiry and activate their thinking, so that students can learn the knowledge of this lesson with strong interest.

Second, explore the method of measuring angle independently

1, recognizing the necessity of using protractor.

You really have a way. If you want to know who flies the kite high, you only need to know the angle formed by the kite line and the ground. But how do you know the angle?

This question further activates thinking, and students will actively participate in the discussion and know the method of angle size, thus leading to the content to be learned in this lesson, "Angle measurement". In communication, students have different ways to know the size of the angle, such as measuring with a smaller angle; Measure with a ruler; Overlap the two angles to compare their sizes; Measure with a protractor.

Here, teachers conform to students' thinking and guide students to use their own methods. In the process of using these methods, students will realize that the method of overlapping two angles is not applicable in this case. Although you can know the size of an angle by measuring it at a smaller angle, you can't know exactly how much one angle is bigger than another. These methods have limitations in use. Only measuring the angle with a protractor is the simplest and most effective. When students have the need to learn, they can put more energy into learning activities.

Step 2 know the protractor

Please take out the prepared protractor and observe it carefully. What do you see?

Report on students' free exchange.

Know the center point on the protractor, 0 scale line, internal and external circle scale, 18 big square, 180 small square, 1 angle. Knowledgeability is a unit for measuring angles.

This is what students see when they get the protractor. Guiding students to talk about what they see can help them become more familiar with protractors and keep their interest in learning. Here I will guide the students to report freely first, and then demonstrate the principle of angle measurement with protractor and the names of each part with multimedia. Help students form a more complete understanding.

Step 3 find the angle on the protractor

Your eyes are really bright. You have discovered so many secrets of protractor. In fact, there are still many angles hidden on the protractor. Can you try to find them? Please draw the corner you found on the exercise paper.

The students tried to draw angles on the protractor on the paper.

Which corner did you find? Do you know how big this angle is?

Let the students show their horns in front and try to say how big it is.

This activity is actually the process of experiencing the measurement angle. In this process, students realize that the central point of the protractor is the vertex of all angles, and any two rays drawn from this vertex can form an angle, and each angle can know the degree, paving the way for measuring the angle later.

4. Try to measure this angle

You found so many angles on the protractor. Can you try to measure the angle with a protractor?

Measuring angles with a protractor should be something that students have long wanted to know. After students know the protractor, guide them to try to measure the angle, and the content to be learned will come naturally.

The students try to measure several angles on the exercise paper. The opening of a given angle is left, right and downward. The purpose is to enable students to gradually master the method of measuring angle in hands-on practice, independent exploration and cooperative communication, and to study and solve the problems encountered in measuring angle, such as reading the inner circle scale or reading the outer circle scale; It is easier to align one side of the corner with the "0" tick mark, and so on.

This kind of teaching is the aforementioned "learn to do things, teach to learn, teach in the way you learn, and learn in the way you do." Teachers should be familiar with students' learning thinking, guide them according to their thinking, pay attention to students from a higher angle, and promote the formation of students' learning ability in the process of learning.

5. Summarize the methods of measuring angles.

Just now, when showing the angle measurement method, the students have several similarities. Did you find them?

Guide students to exchange and summarize the methods of measuring angles, that is, the center point of the protractor should coincide with the vertex of the angle, and one side of the angle should coincide with the "0" scale line of the protractor, depending on the scale on the other side. Because students personally participate in it, they have a profound understanding of how to measure the angle bit by bit in practice, so the matters needing attention in angle measurement can be summarized more completely, and the essence of angle measurement can be deeply understood, and the skills of angle measurement can be gradually formed. Thus, the learning of the main content of this lesson has achieved the effect of waterway completion.

Step 6 solve the problem

Students can already measure the angle with a protractor, so we can help the little monkey judge who is flying the kite high.

Students use what they have learned to help the little monkey solve problems in life, which makes the situation created earlier more complete, cultivates students' awareness of applying mathematics, enhances their confidence in learning mathematics, and feels the value of learning mathematics. More importantly, students have experienced the joy of learning and success, and their inquiry consciousness and ability have been developed.

Third, the use of measuring angle is realized in connection with life.

Show examples of measuring angles in life: the angle of slideway; Angle of inclination of chair backrest; Choose the shooting position when playing football; This paper makes full use of the abstract angle in multimedia demonstration life to make students feel the role of angle measurement, broaden their horizons, give students room for further thinking, let students feel the wide application of angle measurement in life, stimulate their confidence in learning mathematics well, cultivate their consciousness and habits of observing life with mathematical eyes, and appreciate the value of mathematics.

Write on the blackboard.

When students summarize the angle measurement methods, write them on the blackboard according to the students' communication, so as to help students understand and master the key points and difficulties of this lesson and play the role of making the finishing point.

Angle measurement

The vertex of an angle-the center

One side of the angle 0 tick mark

The other side of the corner?