以往《砂和黏土》的教学用一课时就可完成,先用感官对砂和黏土进行直接观察,再将它们与适量的水混合,借助手的揉搓比较二者的差异,之后将二者置于实验装置下,进行渗水性实验。经过一系列的观察比较后,学生在头脑中建立起砂和黏土各自的特点。这样的教学,虽然有较强的完整性,但对于三年级学生而言,容量过大,每个探究小活动都仅仅是隔靴搔痒,蜻蜓点水。师生都在为了完成 In the past, the teaching of “sand and clay” could be finished in one lesson. First, the sand and clay were directly observed with the sensory organ. Then they were mixed with the appropriate amount of water and rubbed by hand to compare the differences. Then, Under the experimental device, water permeability test. After a series of observations and comparisons, students established their own characteristics in sand and clay. Although such teaching is more complete, for the third graders, the capacity is too large, and every inquiry activity is just a tickle and superficial. Teachers and students are in order to complete