Representative Chemical Oxide Demand (abbreviated: COD) values of Sumida River\u27s water and its variation factors of student\u27s experiment of junior high and high school science teacher candidate course students (30 students) of the Department of School Education, Teikyo University of Science, were discussed in this article. First, effective method of measurement and calculated results were shown and then contributing factor of error was considered from student\u27s reports and questionnaire results. Student\u27s experimental results showed significant difference by tidal movement. As explanation of the relationship between chemical experiment and natural phenomenon would stimulate student\u27s interests of science, student\u27s surrounding living environment might be used for effective science education material for students. Each student group\u27s COD measurement results showed significant error span. For getting better results, itwould be necessary to accurate operation, such as solution adjustment and titration procedures. Though questionnaire results showed almost positive opinion, easier understandable textbook and appropriate explanation through experimental class would be necessary to give useful knowledge about chemistry to students
