This study was designed to identify students' misconceptions concerning frictional force, and Newton's laws of motion. It was also designed to determine the effectiveness of using instructions based on students' misconceptions to improve the teaching of physics. A pencil-and-paper test was administered to three groups of 16-year-old students: average students, above average students, and gifted students. Some common misconceptions were listed and comparisons of misconceptions among the three groups were illustrated. To ovecome students' misconceptions, a teaching unit with instructional materials using students' misconceptions was designed. The instructional strategy suggested by the principle of conceptual change was developed for students in the experimental group. Statistical analysis of data showed that students in the experimental groups performed significantly better and with fewer misconceptions as compared with students who learned the same concepts and laws through the usual way of lesson delivery. A 20-item test for identifying the misconceptions is appended. (YP)