Study On The Prototype Theory Be Applied In Teaching Of The High School Chemistry

Prototype theory is an important category theory developed based on the critisism of the classical category theory. It is an important point of view of cognitive linguistics, serving as the theoretical basis and core of cognitive linguistics and being of great advancement. The basic mode of classroom teaching of chemistry in high school fits well with the prototype theory, which therefore could be utilized to guide the teaching of high school chemistry. The prototype theory considers "prototype" as the best and most clear example of the category, which is the reference of categorizing atypical cases. Therefore, selecting the best prototype in teaching makes it easier for the students to accept and understand new concepts and to improve their abilities in solving problems; while inappropriate usage of prototype would lead to the consequence that the students have difficulties in building up the concept or cannot build up the concept at all. Under the guidance of this theory and through case studies of actual teaching, we discuss how to select an optimal prototype in high school teaching of chemistry.In this dissertation, studies were carried out with focus on three representative topics in high school chemistry textbooks. The first topic is the teaching of "the unit of the amount of a substance-mole". During teaching of "mole" most high school teachers would use "rice", "cigarette" or "staple" as examples, while a few teachers use "lightyear". The author added "astronomical unit" and employed all these examples as prototypes to carry out a questionnaire among fresh students in Grade One. The results suggest that "lightyear" is the best prototype. The second topic is the teaching of the concept of "electrolyte". We selected two parallel classes to carry out a control teaching, where the three core examples, HCl, NaOH and NaCl were employed as prototypes in one class and a lot more prototypes were used in the other class. The results suggest that the latter has a better teaching effectiveness. The third topic is "primary battery". Two parallel classes were again selected in control teaching, where the copper-zinc primary battery was used as teaching prototype in one class and primary battery containing salt bridge was used as prototype in the other class. The results suggest that the copper-zinc primary battery offeres a better teaching effectiveness.Our research indicates that the selection of appropriate prototype should obey several rules.(1) Prototype should be the most typical example of the category. The more typical the prototype is, the easier to help students solve problems.(2) The prototype should be familiar to the students. The students has a greater acceptance to those prototypes they are familiar, and the teaching will be more effective.(3) One or more prototypes can be used. In actual teaching, a proper number of prototypes will help teaching better.(4) When choosing prototypes, the "acceptibility" of the prototype itself should be taken into account. If an overcomplicated prototype was used, the students would have difficulties in accepting and understanding, and the teaching effectiveness would not be satisfactory. In such case a less typical but easier and more acceptable member of the category can be used as the teaching prototype.