Ski lifts, bowling balls, pipe system or waterfall? Lower secondary students’ understanding of analogies for electric circuits.

Electric circuits are challenging for students to understand, and a wide range of analogies are developed in order to support their learning. This article investigates how lower secondary students understand four analogies presented in teaching material for science for Norwegian schools. The analogies compare electric circuits to a ski lift, a water pipe system, a waterfall and moving bowling balls, respectively. Data in the study consist of group interviews with 12 students in lower secondary school, about how they understand the analogies. Results show that students are able to reason about continuity and the concept of current in circuits based on all the analogies, but that the concept of voltage remains a challenge. It seems from the results that analogies relating voltage to energy transfer as an effect of height difference in a gravitational field are constructive, despite the need for the more abstract concept of field. In addition, the results demonstrate that weaknesses in how the analogies are presented may cause major problems for students in building a fruitful understanding. This kind of weaknesses are prevalent in the teaching material studied.