对物质密度的测量,能够较好地反映学生的创新能力和对知识的灵活应用能力,因而一直是各地中考的重点和热点,也是学生学习的难点。而密度是单位体积的某种物质的质量,是物质的一种特性,由定义式ρ=m/V可知,要测量物质的密度就必须测出物体的体积和质量,这就要求学生能恰当地选用 The measurement of material density can better reflect the student’s ability to innovate and the ability to apply knowledge flexibly. Therefore, it has always been the focus and hot spot of local exams, and it is also a difficult point for students to learn. The density is the mass of a substance per unit volume. It is a characteristic of a substance. The definition formula ρ=m/V shows that to measure the density of a substance, it is necessary to measure the volume and quality of the object. This requires the student to be appropriate. Selection