We describe a new teaching approach in mechanics for junior high school (JHS) and high school (as an introduction) that requires around 15–30 teaching hours. The approach guides students to explain and predict qualitatively, using physical terms, a class of everyday phenomena and situations in mechanics (see Fig. 2) by applying a qualitative understanding of Newton's laws, especially the third law. The approach also aims to change students' interest in physics and their views regarding its importance. It was tried out extensively with heterogeneous ninth-graders and has also been integrated into the teaching of mechanics at the advanced high school level.

Figure 2.

This method takes a systems approach and does not detach the object from its surroundings. It encourages students to analyze the interactions among components of the entire system before focusing on a specific object and constructing its free-body diagram. Students learn to systematically identify short and longterm interactions and to characterize the mutual influences on shape and/or speed of interacting objects. A qualitative study of basic motion concepts is followed by a qualitative study of Newton's second law, dealing mainly with situations in which objects start or stop their motion. We found that although the previously described framework helped students to construct qualitative explanations, many students were still unable to formulate such explanations. We hypothesized that in addition to the conceptual framework, students need a qualitative problem-solving strategy that would guide them through the problem-solving process.^11,12,13