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教学片断一师什么叫压力?生垂直作用在物体表面的力叫压力.师压力的作用效果跟哪些因素有关?生1 压力的作用效果跟压力大小有关.生2 压力的作用效果跟受力面积大小有关.师很好.其他同学有没有不同的看法?生没有了.师如何探究压力的作用效果跟压力大小和受力面积大小的关系?请同学们用课桌上的小方桌模型、细沙、钩码等器材,小组合作,用“控制变量”法来制定计划、设计实验、操作探究.……师你们是怎样探究压力作用效果跟压力大小、受力面积大小的关系的?生实验分两步:首先将小方桌四脚朝下放在细沙上,再将小方桌桌面朝下平放在细沙上.观察两种情况中,小方桌在细沙中陷入的深度,比较在压力相同的情况下压力产生的效果与受力面积的关系;其次,将小方桌四脚朝下放在细沙上,依次将钩码放在桌面上.观察小方桌在细沙中陷入的深度,比较在受力面积相同的情况下压力产生的效果与压力大小的关系.这时老师在多媒体屏幕上同时动态显示这一
What is the stress of a teaching division in a division? The force acting perpendicularly on the surface of an object is called stress. The effect of the divisional stress is related to what factors? The effect of stress on a student is related to the stress level. The effect and stress area of the student 2 stress. The size is relevant. The teacher is very good. Other students have different opinions? There is no life. How does the teacher explore the effect of stress on the relationship between the size of the stress and the size of the stress area? Ask the students to use the small square table model on the desk, Sand, hook code and other equipment, group cooperation, use “control variables” method to formulate plans, design experiments, operational exploration. ... ... How do you look at the effect of pressure on the pressure effect, the size of the force area? The biological experiment is divided into two steps: first, place the small square table on the fine sand with four feet down and place the small square table top down on the fine sand. Observe the depth of the small square table sinking in the fine sand in both cases. The relationship between the pressure and the stress area under the same pressure; Secondly, put the small square table on the fine sand with four feet down and place the hook code on the table in turn. Observe the depth of the small square table sinking in the fine sand. Compare In the subject The relationship between the effect of pressure and the size of stress in the case of the same force area. At this time, the teacher dynamically displays this on the multimedia screen.