The area of a circle is taught on the basis that students master the meaning of the area and the calculation method of the area of a plane figure such as a rectangle or a square, know the circle and can calculate the circumference of the circle. Teachers of these two courses can grasp the teaching materials scientifically, carefully design and effectively carry out teaching activities, which fully embodies a teacher's basic teaching skills and teaching philosophy under the background of the new curriculum, paying special attention to following students' cognitive laws, attaching importance to students' thinking process of acquiring knowledge and attaching importance to life experience from students. There are many highlights in the two classes. Let me talk about my personal shallow understanding and feelings.
1, situational lead-in can stimulate students' interest in exploring new knowledge and review effectively.
By reviewing the area of triangle and bamboo quadrangle, the figure is transformed into the learned figure to calculate the area, which makes necessary preparations for students to derive the formula for calculating the area of a circle by using the method of figure transformation, so that students can understand that the idea of transformation is one of the effective means to learn new knowledge, and stimulate students to transform the circle into the learned figure to prepare for area calculation.
2. Guide students to actively participate in the process of knowledge formation.
The teaching focus of this course is the derivation of the formula for calculating the area of a circle. In teaching, after guiding students to put forward the conjecture of "dividing the circle and assembling it into a receiving figure", students are organized to divide the circle into 16 and 32 equal parts respectively, and then assemble it into an approximate parallelogram for operation, so that students can realize through reasoning that "the more points, the closer the assembled figure will be to a rectangle." Find the relationship between the circle and the assembled approximate rectangle, and deduce the area of the circle according to the formula for calculating the area of the rectangle. Calculation formula, students' participation in the process of knowledge formation, not only helps to understand and master the calculation formula of circular area, but also cultivates their innovative consciousness, practical ability and ability to explore problems, learns some mathematical methods and further develops their preliminary concept of space.
3. Fully embody the concept of "efficient classroom" with students as the main body.
Students are the masters of mathematics learning. This lesson is to guide students from the known to the unknown, to understand the meaning of circular area, and to challenge. The question encourages students to explore the law of graphic transformation independently, and summarizes the calculation formula of circular area on the basis of full perception, which provides students with the opportunity to observe, guess and experiment. Dynamic opportunities enable students to actively participate in the process of knowledge formation, cultivate students' innovative consciousness, practical ability and exploration ability, and develop preliminary spatial concepts. In addition, students can finish classroom exercises independently, which also cultivates their good study habits and the spirit of independent thinking and overcoming difficulties.
4. The organic combination of multimedia courseware and classroom teaching, ingenious and natural application, has realized the multimedia resource-based teaching service and improved the efficiency of classroom teaching.
Of course, this course also has several aspects worthy of discussion and improvement:
1. We should fully tap the teaching material resources and further cultivate students' divergent thinking. This lesson can guide students to fold a circle into a triangle and try to deduce the formula of the area of the circle. This is not only conducive to cultivating students' divergent thinking, but also can achieve the same result through different routes.
2. Teaching should be geared to all students and take care of students with learning difficulties to master knowledge.
In short, today's programs are excellent courses, which not only fully show the concept and style of teaching and receiving that the teacher first talked about, but also set an example for us, which is worth learning and exploring.