一、知识网络二、复习指导（一）浮力产生的原因1．浮力产生的原因浸入液体（或气体）里的物体受到的向上压力大于向下压力，这两个压力的差就是物体受到的浮力．即：2．浮力的方向竖直向上．注意（）浸在液体以的物体不一定受到浮力．例如，有一些物体底而紧贴容骼底，物体只 First, the knowledge network Second, review guidance (a) the cause of buoyancy 1. Causes of buoyancy The object immersed in liquid (or gas) is subjected to upward pressure greater than downward pressure. The difference between the two pressures is the buoyancy of the object. That is: 2. The direction of buoyancy is vertical. Note that objects immersed in liquids are not necessarily subject to buoyancy. For example, there are some objects that cling to the bottom of the shell and the objects only