“改变浮标的沉浮”是《改变物体在水中的沉浮》一课中的第二个活动。这个活动让学生研究各种使浮标上浮或下沉的方法,但侧重于通过改变体积的大小来改变浮标的沉浮。有位教师对这个活动进行了研究,在几次试教时分别给学生提供了三种不同结构的浮标,产生了不同的教学效果。 “Change the buoy of the buoy ” is the second activity in the lesson of “Change the object in the water”. This activity allowed students to explore various ways to float or sink a buoy, but focused on altering buoyancy by changing the size of the buoy. A teacher conducted a research on this activity and provided three kinds of buoys of different structures to students respectively during several teaching trials, resulting in different teaching effects.