Some problems in First Steps of Studying Electricity (II) On Understanding of Electric Currents and Voltage in Lower Secondary School

Abstract

It is well known that the concepts of electric currents, voltage, electric power, etc, are difficult to understand in first steps of studying electricity. The authors investigated the difficulties of studying electric currents in elementary school and reported formerly. This work involves investigations of some problems of studying electricity in lower secondary school. Process of research is as follows: (1) Research for the understanding of electric currents studied in elementary school (pre-test) (2) Planning and execution of lessons of a unit "Electric Currents", based on the course of study of lower secondary school (1977) and refering to the results of above research (3) Measurement of effects of the learning, one (post-test) of which was the same as the pre-test and the other (examination) was a new test concerning electric currents and voltage, prepared by one of the authers (4) Full analyses of correlations among auswers of two or three problems of each test and between two tests Main results are as follows: (1) From analyses of the results of the pre-test and the post-test, there were found four types of thinkings of pupils about electric currents and they were characterized, though it was very difficult to know how pupils were thinking them. It was concluded, also, that these four types corresponded to each step of the understanding of electric currents. (2) From the analyses of answers in the test (examination), a guiding line in teaching-- the unit "Electric Currents" was proposed, which is to enphasize a law of conservation of electric currents in a closed circuit and to promote the understanding of the relations between electric currents and voltage.