This study was conducted to examine the effects of integrating the prediction,observation,and explanation model(POE)into the building blocks course on facilitating the preschoolers' acquisition of gear concepts.The preschoolers' alternative conceptions of gears after the treatments were also investigated.60 preschoolers were recruited and randomly assigned into either an experimental group or a control group.The former received the building block course with the POE model embedded,the latter received the base course.The measurement included the pretest,posttest,and two-week delayed test.The course included four one-hour treatments and each participant was instructed individually during the treatment and the tests.The findings indicated that integrating the POE model into the building block course could effectively enhance the preschoolers' acquisition of gears concepts.However,some alternative conceptions were identified after the treatments,such as “Two gears with different sizes interlock.The bigger the gear,the faster its turning speed.”