Discrepant questioning is a teaching technique that can help students "unlearn" misconceptions and process science ideas for deep understanding. Discrepant questioning is a technique in which teachers question students in a way that requires them to examine their ideas or models, without giving information prematurely to the student or passing judgement on the student's model. This strategy prompts students to see the contradictions in their own model. This study focuses on the analysis of small group tutoring sessions on human respiration. Four 2-hour classes were held with a group of 4 eighth-grade students. The group included two boys and two girls and was ethnically diverse. The students were instructed with a Standardized Teaching Sequence based on model construction and criticism theory developed in 1998. The instruction was organized around five individual target models related to the microscopic structure of the cell; internal structure of the cell; and the digestive, circulatory, and respiratory systems. Evidence suggests that students had a marked increase in comprehension of human respiration. Quantitative analysis showed that the small group had an overall significant mean difference of over three standard deviations on the pre- to post-test. (MVL)