The aim of this paper is to expose impacts of teaching through SL in the topic of internal structures of power transformers for undergraduate students in department of electricity and energy at Usak University. We begin with introducing the subject taught with traditional methods and through Second Life. We then analyze the findings with Mann-Whitney U and Wilcoxon Signed Ranks tests using SPSS software. We draw the conclusion by indicating that SL made an effective contribution to the students' knowledge acquisition while the contribution of traditionally teaching methods in increasing success of the students cannot be ignored. (C) 2013 The Authors. Published by Elsevier Ltd.