本研究開發再結晶實驗技能精通學習教材及教學策略，以使學生達到三個連續的學習達成階層：具體、辨認及歸納階層，其效果可用學生學習進步的情形加以評定，並用差、後測之間，實作成果與測驗成績之間，以及一組實驗活動之間等的正相關來評量。學生學習的進步情形，可由在一組實驗活動中S曲線向右移動，P曲線向下移動看出來。紙筆測驗每一試題的CP□值都小於0.40，以各題的P□對CP□作圖，所有試題均位於左上方象限中，此等結果顯示所有試題都良好，每位學生的CS□都小於0.40，三個學習達成階層後測2的D��值都低於0.3896，紙筆測驗分數高的學生，其再結晶實作所得的晶體產率高，純度也高，其一致程度在具體與辨認階層皆為100％，在歸納階層為91.3％，這些事實可由每位學生學習進步情形得到驗證。由以上結果可以顯示本研究所開發的再結晶實驗技能精通學習教材及教學策略，對於再結晶實驗技能的精通學習相當有效，90％以上的學生都達到歸納階層，故適合於大二有機化學實驗課程。本研究所用的方法，可推廣應用於其他化學實驗技能的教學研究上。

　　　　　Chemistry research supervisors are often frustrated by the fact that students are not well equipped with the necessry laboratory techniques at the start of their research programs. The purpose of this study is to design a method of implementing mastery learning of the recrystallization technique to develop students' ability in performing it correctly, as well as using the technique to solve chemistry problems they will encounter later, in other words, achieving transfer of learning. Instructional materials and strategies were developed and organized to bring the students up to three successively highter learning levels: concrete, identity, and classificatory. The instruction was assessed by the degree of learning progress, which in turn was evaluated by positive correlations between two consecutive tests, between task performance and test results, and among the results of a set of laboratory aassignments. Progress of learning was observed in the rightward shifts of the S-curves and the downward shifts of the P-curves during a set of assignments. CP□ values of all items wee less than 0.40. In the plots of P□ vs. CP□, all items were in upper left quadrant. These results indicate that all items wre of good quality. An acceptably small degree of anomalous item patterns reflected unambiguous instruction. In each post-test 2 for the three levels all the CS�� values for individual students wre less than 0.40 and all the three D�� values were less than 0.3896. Small CS�嫵nd D�� values indicate an acceptably small degree of learning difficulties and erratic studies (careless mistakes, copying or guessing responses) after instruction. Those students (100% for both the concrete and the identity levels and 91.3% for the classifictory level) with high scores in the paper-pencil test indeed obtained high yield and high purity. These facts were consistent with the learning gain shown in individual performance profiles. Once the students mastered the technique, they kept the ability. The progress of learning observed as discussed above indicated the effectiveness of our implementation method for mastery learning of recrystallization technique. These instructional materials and strategies were satisfactory for the college introductory organic chemistry labortory course. The methodology used in this study can be extended advantageously to the study of instruction on other chemistry experimental techniques.