Lecture notes on the Understanding of Parallelogram, Volume II, Grade Four 1 1. Teaching materials.
Lecture content: Jiangsu education publishing house, fourth grade, second volume, 43~45 pages.
Second, the position, function and significance of teaching content.
Understanding parallelogram This course is based on students' intuitive understanding of parallelogram, their preliminary understanding of the characteristics of rectangle, square and triangle, and their understanding of parallelism and intersection. Through a series of exploration and practice activities, they constantly know the characteristics of parallelogram, parallel equilateral, the base and height of parallelogram. This part is the basis of studying parallelogram area in the future, which is conducive to improving students' practical ability, enhancing students' innovative consciousness and further developing students' interest in "space and graphics".
Third, say the goal.
1, knowledge and skills target
(1) Understand the concept and characteristics of parallelogram.
(2) Knowing the base and height of the parallelogram, we can draw the height.
(3) Cultivate students' practical ability, observation ability and analysis ability.
2, process and method objectives
Let students explore new knowledge through hands-on operation, eye movement observation, verbal expression and brain thinking.
3. Emotional attitudes and values goals
Let students feel the close connection between graphics and life, and feel the joy of successful exploration.
Fourth, talk about the difficulties in teaching.
Key point: Understand the characteristics of parallelogram. Know the base and height of the parallelogram.
Difficulties: Make the height of parallelogram, and understand the corresponding relationship between base and height.
5. Teaching and learning methods.
(A) teaching methods:
According to the characteristics of the textbook of this course, in order to highlight the key points and break through the difficulties more effectively, according to the students' cognitive rules, and following the guiding ideology of "teacher-oriented, student-oriented and training-oriented", the observation and discovery method is adopted as the main method, supplemented by the multimedia demonstration method. In teaching, design inspiring thinking questions, create problem situations and guide students to think. The timely use of audio-visual media in teaching can stimulate students' desire to explore knowledge and gradually draw conclusions, so that students are always in a positive state of actively exploring problems, thus cultivating students' thinking ability.
(2) Speaking and learning methods
1, according to the principle of autonomy and difference, let students participate in the occurrence, development and formation of knowledge independently in the learning process of "observation → guess → generalization → verification → communication → application", so that students can master knowledge.
2. Students can solve more than one problem, guide students to sum up methods in time and overcome the mindset. The example explanation adopts the method of decomposing graphics, so that students can experience and learn the "transformed" mathematical thought.
3. Use the graphics in real life to make the process of acquiring new knowledge natural, enhance students' sense of accomplishment and self-confidence, and thus cultivate a strong interest in learning.
Six, said the preparation of teaching AIDS and learning tools
Teaching AIDS: triangular, parallelogram paper, rectangular movable frame, small blackboard, etc.
Learning tools: triangle, parallelogram paper, protractor.
Seven, talk about the teaching process.
Activity 1: Use examples skillfully to stimulate interest introduction.
The courseware shows a group of parallelogram pictures in life. Ask the students to find out which plane figures are there. Speaking of parallelogram, flash it again with red courseware. Then ask the students to talk about which objects in life are parallelograms. After summing up, the teacher and students asked, "Do you want to know more about parallelogram?" The teacher wrote the topic on the blackboard.
(Design intention: Let students understand the close relationship between mathematics and life with examples in life, stimulate their interest in learning by asking questions, generate the desire to explore new things, and understand the content of inquiry. )
Activity 2: Practice and explore new knowledge.
Let the students use the prepared parallelogram paper to look at the characteristics of the edges and corners with their eyes, and then actually measure them with a ruler and protractor, and fill in the results in the "My Discovery" report. Then let the students say what they have found and praise those who have found more in time. Teachers and students write the characteristics of parallelogram on the blackboard.
The teacher then asked, "We have just studied the characteristics of parallelogram, so how to define parallelogram?" Discuss in a low voice in the same group. Teachers and students summarize and write down the definitions on the blackboard. )
(Design intention: Let students operate by themselves, acquire new knowledge, and cultivate their hands-on ability, brain ability, analysis and induction ability. I am deeply impressed by what I have learned. )
Activity 3: Teachers demonstrate and students observe.
The teacher used a rectangular movable wooden frame, grabbed the two opposite corners with his hands and pulled inward and outward. Ask the students to observe what changes have taken place and explain the nature of parallelogram. Teachers and students summarize the essence of blackboard writing.
(Design intention: physical demonstration, so that students can acquire new knowledge more intuitively and vividly. )
Activity 4: Teachers and students Qi Xin work together to break through the difficulties.
Let the students follow the teacher with parallelogram paper in their hands. The teacher talks about folding while doing it. Then the unfolded crease is the height of the parallelogram. Explain that the edge perpendicular to the height is the bottom. Please draw the height with a pen and triangle and mark it. Fold several heights in the same way and observe the characteristics of heights. Then teachers and students write down the definition and characteristics of high and low on the summary board.
Design intention: In this link, it not only embodies the teacher's guidance and students' learning, but also cultivates the ability of hands-on and brain. The difficulty has been well broken through. )
Activity 5: Consolidation Exercise (Courseware Demonstration)
1. Which of the following figures is a parallelogram?
2. Can you find out the graphics you have learned from the picture below?
3. Mark the bottom and height of the parallelogram in the picture below.
The second volume of the fourth grade, Understanding of Parallelogram, said lesson draft 2. First of all, the textbook says
1, teaching content analysis
The area of parallelogram is students' understanding of quadrilateral, triangle and trapezoid after mastering the characteristics of parallelogram and calculating the area of rectangle and square. Teaching is based on knowing the base and height of parallelogram, mastering the formula on the basis of understanding, and applying the theory of transfer assimilation to bring the new knowledge of parallelogram area calculation formula into the existing cognitive structure. It is helpful for students to learn the derivation method and prepare for the derivation of triangle and trapezoid area formulas.
2. Teaching emphases and difficulties:
Teaching emphasis: understand and master the calculation formula of parallelogram area and calculate the area of parallelogram correctly.
Teaching difficulties: understanding the derivation method and process of parallelogram area formula.
Second, oral teaching methods
The whole teaching consists of review and introduction, inquiry experience and practical application. In the introductory stage, students feel that there is an internal connection between rectangle and parallelogram, and review the characteristics of rectangle and parallelogram and the calculation formula of rectangle area. Lay a foundation for learning new knowledge in the future.
In the exploration and experience stage, it is divided into three levels. The first level is counting squares. It is too much trouble for students to experience the method of counting squares alone, so we must find a simpler method to calculate the area of parallelogram. By "Why are different graphics equal in area?" Find out the relationship between parallelogram and rectangle, and then boldly guess what the area of parallelogram may be equal to? The second level, explore the calculation formula of parallelogram area. In this process, I first assigned two tasks:
1. How to transform a parallelogram into a learned figure?
2. What is the relationship between the parallelogram and the converted graph? Fill in the experimental report, so that students can have a clearer purpose in the process of operation. Then in the process of students' operation, the teacher pays attention to the operation and methods of patrolling students, gives guidance and lists typical methods. I have considered several situations in advance. Then, in the process of students' reporting, teachers pay more attention to the accuracy of students' language and emphasize "translation". Finally, there is a teacher's question: "What has changed and what has not changed in the process of transformation." Students combined with the report form to draw the following conclusions: the area has not changed, the shape has changed, the base of parallelogram is equal to the length of rectangle, and the height of parallelogram is higher than the width of rectangle. Because the area of rectangle is equal to the length and width, it is successfully concluded that the area of parallelogram is equal to the height of the base. In this way, the students summed up the calculation formula of parallelogram area by cutting, moving, spelling, observing, comparing and summarizing. Let the students really move and experience the derivation process of the formula. The third level is the letter expression of self-study formula to cultivate students' autonomous learning ability.
In the practical application stage, it is divided into basic contact and expansion exercises. In the basic exercise, first complete the example 1 and use the formula to directly calculate the area. Then pay attention to let the students measure by hand, let the students actively find the necessary conditions for calculating the area, and find the area according to these conditions. Finally, change the posture of the parallelogram, so that students can accurately find the bottom and height, and calculate the area to complete 1 and 2 questions. Through this part of exercises, students' understanding and application of area formula will be further consolidated.
In the outward bound training, first of all, we arranged judgment questions and multiple-choice questions. Through discrimination and selection, students can further understand that the area of parallelogram is related to two factors: base and height. Calculating the area in units of area requires a set of corresponding foundations and higher-level knowledge. Then an open topic appeared: "The area of parallelogram is 24 square centimeters. What is its base and height? " ? (base and height are integers). What if there is no limit to decimals? It not only enlivens students' thinking, but also pushes this class to a climax. Finally, a rectangular box for thinking appeared, with length 15 cm and height 10 cm. What are the perimeter and area respectively? What about the perimeter and area of parallelogram? Through this part of practice, students can deepen their understanding and application of parallelogram area formula, and achieve the purpose of mastering and using it flexibly.