A calculus-based introductory physics course, which is based on the Matter and Interactions curriculum of Chabay and Sherwood (2002), has been taught at Purdue University. Characteristic of this course is its emphasis on modeling. Therefore, I would like to investigate the effects of modeling-based instruction and interactive engagement on students' physics understanding. For this reason, The Force Concept Inventory (FCI) (Hake, 1992) as pre- and post-test was used to evaluate students learning and understanding following a newly developed approach to teaching mechanics in an introductory physics course. The results lead that it can be concluded that the modeling-based interactive teaching method helps students to improve their understanding and learning physics.