Resumen de Activities to Help High School Students Understand Newton’s Second Law of Motion
Joseph El Helou, Calvin S. Kalman
Traditional labs might perform well when tasks are mainly about procedures and measurements.1–5 They fail, however, when it comes to conceptual parts like the conceptual part of Newton’s second law. In this paper, we discuss how a combination of labatorials based on the two-way motion of a fan cart with reflective writing helps high school students understand Newton’s second law of motion. Many students presume that a body falling freely vertically downward follows what is called the long-decay model: The long-decay model assumes that the force is absorbed into the body and decays. At the top of the motion, this impressed force matches that of gravity, and just after this, the impressed force is less than that of gravity and the body begins to fall. Some students follow a modified version of the long-decay model in which the impressed force vanishes at the top of the motion. This model appears to “stitch” a pre-Newtonian view of force and motion (fnet ∝ v) before the turning point to a Newtonian view (fnet ∝ a) afterward. This latter version is called the truncated decay model.
