7th Graders’ understanding of a fire caused by an electrical short circuit

Abstract

The aims of this study were 1) to develop a fire caused by an electrical short circuit learning activity and 2) to survey 62, 7th graders’ understanding of a fire caused by an electrical short circuit. This cause consists of three parts of understanding, which are 1) an electrical short circuit causes the overload current, 2) this amount of current causes high heat, and 3) this high heat increase the temperature of the surrounding materials until the temperature reach to the Ignition Temperature. The Problem Based Learning (PBL) approach was used to design the learning activity. Students were challenged to design their own group experiment to make a combustion with the provided materials: rubber band, paper clip, AA battery, cotton rope, chewing gum with wrapping aluminium paper, and cotton pad. The open-ended question as “How does the electrical short circuit cause a fire?” was used to survey the students’ understanding of electrical fire causes in the case of short circuit. The result revealed that only one student was able to give all three parts of the explanation, two students could give only second and third part of the explanation. While 2, 4, and 18 students could get only the first, second, and third part of the explanation, respectively. Moreover, some misconceptions of current, similar to the previous research, were found such as 13 students described that current was stored at a part of a conductor to generate heat and 10 students thought that current came from both terminals of a battery and clash at the burning point.