不同于教科书中的标准加入法——开放环境下授课的实例

Standard Addition Methods Different from Description in Textbooks:A Case for Teaching in Open Environment

为了加深学生对标准加入法(standard addition methods,SAM)的理解,将其列为"分析化学英文文献选读"选修课的一个专题,在学习资源开放、学习方式开放和学习结果开放的环境下,经过学习阶段、展示阶段和拓展阶段等密不可分的3阶段式问题导引下的主动学习和讨论,获得了有别于目前教科书内容的、鲜活的SAM内容:(1)由目前的2种类型拓展为9种类型的SAM;(2)由目前的外推法SAM拓展为内插法SAM;(3)由目前的容量法SAM拓展为重量法SAM;(4)新近出现的"稀释标准加入校准法"与这里讨论的SAM存在本质差别。在开放的环境下将传统的教学问题与新思路和新应用结合起来是一种行之有效的教学方法。它至少有以下3个优点:(1)以学生已有的知识为切入点,易于学生接受;(2)所选择的材料紧密跟踪分析化学的新进展,可以激发学生的兴趣;(3)课程以专题的形式展开,逻辑线索清晰。

In order to deepen the students to understand the standard addition methods (SAM),we choose it as one of the special topics in the course named selected readings for english iiterature in analytical chemistry.Some lively contents on SAM,which are different from the description in the current textbook,are received in the open environments in terms of learning resources,learning style and evaluation for the learning results,through a series of problem-based active learning and discussion activities which are composed of learning,showing and expanding stages.Firstly,2 types of SAM in the,current textbooks are increased up to 9 types.Secondly, extrapolation method for SAM described in current textbooks is modified with interpolation method for SAM.Thirdly,the volume-based SAM in the current textbooks is expanded to the gravitybased SAM.Fourthly,the newly emerging new method named diluted standard addition calibration is totally different from the SAM discussed here.It is an effective teaching approach combining the traditional concepts in the textbook with their new connotation and new applications in an open teaching and learning environment.It has at least three advantages as follows-First of all,the teaching activities developed are accepted by students because this teaching approach is based on students'existing knowledge.Moreover,the course stimulates students'interests in learning because the reading materials selected in the course closely track the new progress of analytical chemistry.Finally,the logic of the course is clear,since it is composed of some special topics.