“Free-Fall Demonstrations” in the High School Laboratory

As soon as children can see, they observe that objects fall freely. From a young age, we spontaneously construct interpretative models to understand this everyday phenomenon. Over the last three decades, numerous experiments have been developed to help students understand physics concepts regarding free fall. Although there are many "good" educational experiments (e.g., Refs. 3-5), few can be replicated in secondary school laboratories, and most require that students and teachers have advanced experimental skills. Here, we report a collection and sequence of experiments (see Fig. 1) for teaching high school students some core concepts related to the physics of free fall. By using procedures that can be implemented by novices without prior laboratory abilities and by integrating new technologies such as smartphones and free software (Tracker (R)) for video analysis, this paper presents readers with experimental demonstrations that are useful for secondary school laboratories.