In this study, misconceptions about leverage were revealed though the use of a questionnaire for the college students enrolled in the Science Methods class at a university (N=105). The questionnaire includes a question about the balance of a stiff piece of wire hang by string in the middle and bent on one side. Through the analysis of the survey responses, this study identified three types of misconceptions about leverage, namely, a) judgment by the appearance, b) forces other than gravity work, and c) the wire balances when the weight on both sides equal. Based on these findings, a lesson plan was developed using the idea of a conflict map by Tsai. The use of the conflict map helped the researchers to develop a lesson to help students change their misconceptions into correct understanding of the principles of leverage through a step-wise manner. A mock lesson about leverage was implemented to the group of college students who are prospective teachers of science in elementary and middle-school science (N=7). The analysis of the surveys administered before and after the lesson showed that student misconceptions about leverage were changed into correct understanding. Limitations and extensions of the study were further discussed.