A New Experiment to Change Naive Concepts as "Motion Implies a Force" into Scientific Concepts

Abstract

In this study, we devised and evaluated a new experiment for changing such naive concepts as "the force is acting in the direction of the motion" into scientific concepts. Our experiment was based on one of Galileo's thinking experiments. The experimental apparatus was simple, consisting of two connected "Dynamic Carts, small type teaching material," one side being three times the weight of the other, using a soft spring. This apparatus was used to produce constant velocity motion and uniformly accelerated linear motion down or up the slope. The experiment was successful by reappearing. We used a questionnaire for lower secondary school and university students in order to examine their ideas in regard to how the elastic condition of the soft spring would change when this apparatus moved on a horizontal plane at constant velocity. Prior to observation of the experiment, 70% of the students presumed that the soft spring would expand or contract, gaining "force" in relation to the respective weights of the carts. However, during observation, the university students recognized no change in the soft spring, and 40% of these students understood that the force of the cart in itself did not exist. We concluded that this experiment would be effective in changing such naive concepts as "Motion Implies a Force" into scientific concepts.