First, classroom introduction
Let the students recall the three-dimensional graphics they have learned. It is easy for them to say cuboids and cubes in the middle. Then let's talk about the volume calculation formulas of cuboids and cubes. Show cuboids and cubes, and guide students to understand that the volume calculation of cuboids is multiplied by width and height, and the side length of cube volume multiplied by side length is the bottom area multiplied by height. Then guide the students to guess how to calculate the volume of the cylinder.
Second, the teaching process
If there is a guess, it is necessary to verify the correctness of the guess. In the process of exploring the derivation of cylinder volume formula, I first took my children to review the derivation formula of circle area, that is, to convert a circle into a rectangle, so as to get the formula of circle area, and then guided them to convert a cylinder into a cuboid, and compared the changes between the converted cuboid and the original cylinder. Let the children observe what has changed and what has not. In this link, I designed group cooperation. By discussing children's special intelligence, some students even said that they had gained weight and lost weight, and their colors had changed, which I didn't expect. By comparison, the children soon found that the volume formula of a cylinder can also be calculated by the height of the bottom area. After we got the formula, we mastered it by writing, reading, reciting, acting and calculating.
Third, classroom evaluation.
In the course evaluation, the teachers gave me many reasonable suggestions.
1. When talking about the derivation process of the area of a circle, some students can't understand it at once. After a rectangle is converted into a rectangle, its length is half of the circumference. I didn't catch the little details here in class, so I must pay attention to it in the future.
2. When calculating the volume or surface area, it is best to write a formula before calculating, which can reduce the error rate.
3. In the calculation process, π can be reserved in the result and then substituted into 3. 14 for calculation, which can reduce the calculation amount.
Through this open class, there are gains and problems. I hope I can continue to study in the future teaching, improve my professional ability and strive for greater progress in the next lecture!