Analysis of Contents related to Models in the Chemistry Textbooks of the 2009 & 2015 Revised Curricula: Focusing on the Electrolysis of Aqueous Solutions

2009 및 2015 개정 교육과정의 화학 교과서에서 모델 관련 내용 분석: 수용액 전기 분해를 중심으로

Abstract

The purpose of this study is to compare the contents of chemistry textbooks developed according to the 2015 revised curriculum with the contents of the 2009 revised curriculum to research the change in "the development and use of models". To do this, we analyzed 8 kinds of Chemistry I textbooks and 6 kinds of Chemistry II textbooks from the 2015 revised curriculum and compared them with 4 kinds of Chemistry I textbooks and 4 kinds of Chemistry II textbooks from the 2009 revised curriculum. The scope of the analysis was the explanations of the textbooks related to aqueous electrolysis experiments. In order to compare the contents regarding electrolytes when the same experiments are interpreted with different models, we analyzed contents of 4 kinds of middle school science textbooks from the 2015 revised curriculum and 9 kinds of middle school science textbooks from the 2009 revised curriculum. As a result of the analysis, the same experiment was explained by different models according to the grade level and unit, and all explanations were limited to a single model. Also, the tendency to limit the kinds of electrolytes for controlled experimental results is more pronounced in the 2015 revised curriculum than in the 2009 revised curriculum. From this results, we suggest that efforts are needed to reflect the "development and use of models" in chemistry textbooks developed according to the 2015 revised curriculum.

이 연구에서는 2015 개정 교육과정의 교과서에서 "모델의 개발과 사용"이라는 항목에서 변화가 있는지 확인하기 위하여 2009 개정 교육과정의 교과서 내용과 비교 분석하였다. 이를 위하여 2015 개정 교육과정의 화학 I 교과서 8종, 화학 II 교과서 6종을 분석하였으며, 2009 개정 교육과정의 화학 I 교과서 4종, 화학 II 교과서 4종을 비교 분석하였다. 분석 범위는 수용액의 전기 분해에 관련된 내용만 선택하였다. 또한 동일한 실험을 다른 모델로 해석하는 전해질 관련 내용을 비교하기 위하여 2015 개정 교육과정 중학교 과학 2 교과서 4종의 관련 단원 내용을 2009 개정 교육과정의 중학교 과학 2 교과서 9종과 비교 분석하였다. 분석 결과, 학년과 단원에 따라 동일한 실험을 다른 모델로 설명하고 있었으며, 모든 설명은 단일 모델로 제한하여 제시하였다. 또한 모델과 일치하지 않을 수 있는 실험 결과가 나오는 전해질의 종류를 제한하는 경향이 2009 개정 교육과정보다 2015 개정 교육과정에서 더 뚜렷하게 나타났다. 이 결과는 2015 개정 교육과정에서 개발된 교과서에서 "모델의 개발과 사용"을 반영하기 위한 노력이 필요함을 시사한다.

Figure 1. The three spheres of activity for scientists and engineers.¹

Figure 2. Model of science activity.²⁰

Figure 3. Modified model for students’ activity in classroom.²⁴

Figure 4. Modified model in science textbooks.²⁴

Figure 5. A graphic representation of Priestley’s metaphor concerning the growth of knowledge and ignorance.³⁶

Figure 6. The model of electrolysis of water in Chemistry I textbook of the 2015 revised curriculum.⁵³

Figure 7. An electrolysis experiment of chemistry I textbook of the 2015 revised curriculum.⁴⁹

Figure 8. One modern view of the electrolysis of water.⁷⁴

Figure 9. An experiment of electrolysis of water in Chemistry I textbook of the 2009 revised curriculum.⁴⁰

Figure 10. The model to explain the phenomena that current flows when the ionic compounds dissolve in water in Chemistry I textbook of the 2015 revised curriculum.⁵¹

Figure 11. An experiment to confirm existence of charged ions in Science 2 textbook.⁷⁰

Figure 12. The model to explain the phenomena in which electric current flows due to charged ions in Science 2 textbook of the 2015 revised curriculum.⁷⁰

Figure 13. The model to explain the phenomena in which electric current flows due to charged ions in Science 2 textbook of the 2015 revised curriculum.⁶³

Figure 14. An experiment of electrolysis of water in Science 2 textbook of the 2009 revised curriculum.⁶²

Figure 15. An experiment of electrolysis of NaCl aqueous solution in Chemistry II textbook of the 2015 revised curriculum.⁵⁷

Figure 16. Color change of indicator depending on acidity of solution after electrolysis.

Figure 17. Change of carbon electrode after electrolysis in KNO₃ (aq) solution (left), NaOH (aq) solution (right).

Figure 18. Electrolysis of 1M KNO₃ electrolyte solution with in SSC Apparatus.

Figure 19. Electrolysis of KNO₃ electrolyte solution with different concentration in SSC apparatus (The red arrow is the (+) pole, the blue arrow is the (-) pole).

Table 1. Contents of the textbooks developed according to the 2009 revised curriculum

Table 2. Contents of the textbooks developed according to the 2015 revised curriculum

Table 3. The ratio of gas volumes generated by electrolysis according to the concentration of Na₂SO₄(aq)

Table 4. The ratio of gas volumes according to types and concentration of the electrolyte