First, the success of this lesson:
1, focusing on creating scenes improves the teaching quality and efficiency.
In this lesson, Mr. Sun starts with "animal games" and creates problem situations. First, two ants climb the edge of the leaves for a week, so that students can get a preliminary understanding of what perimeter is. The study of mathematical knowledge is boring. At the beginning of the class, the teacher used the situation to attract every student's attention, which laid a good foundation for the next teaching. Next, in order to help students remember that "the length of an object's sideline is the perimeter of this object", Mr. Zhao also designed a situation in which mice ran the race, asking: Are these players running the perimeter of the runway? By comparison, the students came to the conclusion that they were not running on the perimeter of the track, which left a deep impression on the students. This kind of teaching situation has played a very good role in the breakthrough of teaching difficulties. Next, the teacher created the situation of practical activities, and through the process of touching, drawing, measuring and calculating, let the students explore independently and realize the practical significance of perimeter in full experience. The creation of these situations has aroused students' strong interest in learning and improved the efficiency of classroom teaching.
2. Pay attention to students' practical experience and improve teaching quality and efficiency.
Activity is the main way for children to perceive and know the world, and it is also the initial way for children's social interaction. Practical and effective mathematics activities can cultivate students' various abilities. The first teaching link is to let students intuitively perceive that the length of the sideline of a leaf is the perimeter of the leaf by observing the sideline competition of two ants climbing the leaf; Then the teacher created the second teaching link, by tracing the edge of the leaves, the outline of the leaves was obtained, which broadened the students' perceptual knowledge of the perimeter and established a rich representation, thus further understanding the meaning of the perimeter. In the third link, in order to cultivate students' inquiry ability, the teacher organized students to experience a process of understanding the meaning of graphic perimeter and exploring the general graphic perimeter. Many activities are designed, such as speaking, touching and drawing on the level of "intuitive perception"; The fourth step is to measure the perimeter, with a clear purpose, to provide students with enough time and space for independent practice and exploration. When students calculate the perimeter of a plane figure after measurement, different calculation methods appear, and students experience the diversification of problem-solving strategies, which lays a good foundation for learning the perimeter calculation of rectangles and squares in the future. The whole teaching process embodies the concept of "let students experience the whole process of knowledge formation" in the new curriculum standard. Attach importance to students' practical experience, grasp students' hearts, and students learn actively and solidly.
3. Make the best use of the situation, let students explore and discover, and improve the quality and efficiency of teaching.
Exploration and discovery refers to giving full play to students' main role under the guidance of teachers, so that students can participate in the activities of learning mathematics knowledge with their hands, brains and mouths. Teacher Zhao has made two leaps in this class: one is from sensibility to rationality; A leap from rationality to practice. After students have a perceptual knowledge of the perimeter, let them think rationally, such as asking the perimeter of these figures. The students soon thought of measuring the side length of the figure first, but how many sides should be measured? Through observation, it is found that it is not necessary to measure all the edges of some figures, but only once to measure the edges of the same length (such as rectangles and squares); What should I do to find the circumference of this circle? Two cases are discussed: 1, measured with a soft ruler. 2. Roll around the ruler. Let them find the best way to solve the problem through hands-on operation. In this way, students can easily find out the perimeter of these figures under their own exploration and discussion. I think in the future life, if you encounter similar problems, students will definitely use the methods they learned today to solve them, because today's discovery is impressive.
Second, it is worth discussing:
1, the teacher's language is not standardized in teaching. For example, when defining the perimeter, it is said that the length of a graphic week is called the perimeter, and the total length of a complete graphic week should be called the perimeter. Another example: Do rats run around? Should the mouse run around the perimeter of the runway?
2. When students are measuring the perimeter of various figures, the teacher keeps asking questions, which affects the students' operation. In fact, there are not many students who can listen carefully to the teacher's requirements. It will be better if the teacher makes clear the activity requirements before the students operate.
3. The cultivation of students' estimation ability is neglected in teaching. For example, when measuring the perimeter of various figures, students can estimate first and then measure.