小学生实际动手操作,能加深概念的理解,牢固地掌握基础知识,提高能力。教学中,我是这样做的: 一、学生仿教师演示操作。如什么是“横截面”学生不易理解,教学时,我让学生每人带一块泥,按教师指导捏成不同的柱体。首先由我动手将底面是梯形的柱体用刀横切下去,让学生直观地认识横截面,观察得出这个柱体的横截面是一个梯形。随后学生仿教师切割各种不同的柱体,并让学生观察各个柱体横截面是什么形状。在此基础上,再让学生想象堤坝、水渠、水管等的横截面是什么样的图形。这样学生在理解概念的本质属性的同时,既增强了空间观念又为学习柱体体积打下了良好基础。二、学生仿课本图示操作。如教三角形和梯形面积公式时,我首先让学生将自备的两个相同的三角形 The hands-on operation of primary school students can deepen the understanding of concepts, firmly grasp the basics and enhance their abilities. Teaching, I did this: First, the students imitation teacher demo operation. As for what is “cross-section” students do not understand, teaching, I let the students each with a piece of mud, kneaded into different columns according to the teacher’s instructions. First of all, I started by the trapezoidal cylinder with the bottom cross-cut with a knife, allowing students to intuitively understand the cross-section, observed that the cross-section of the cylinder is a trapezoid. Students then imitate the teacher cut a variety of different columns, and let students observe the shape of each cylinder cross-section. On this basis, let the students imagine what kind of graphics cross-section of the dams, drains, pipes and so on. In this way, students not only understand the nature of the concept, but also enhance the concept of space and lay a good foundation for learning the volume of the column. Second, the students imitation lesson icon operation. When teaching triangle and trapezoidal area formulas, I first ask students to bring their own two identical triangles