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A smartphone magnetometer is used to record the magnetic field of a freely falling point dipole magnet. The recorded magnetic field vs. time data are analyzed in accordance with the spatial dependence of the magnetic field to calculate the acceleration due to gravity g. The experiment gives local g to be 9.79 ± 1.9% m/s[superscript 2].

Kinematic models are often very useful. The back and forth throw of a ball between two ice skaters may help us appreciate the meson exchange theory of Yukawa. If the skaters throw the balls at each other, they move backward, which is equivalent to a repulsive force between them. On the other hand, if they snatch the ball from each other, the result will be akin to an equivalent attractive force between them. Such illustrative models may help us understand advanced concepts.

One student (say A) holds a smartphone (with its accelerometer measurement function on) away from the other participant (say B), whose reaction time is being measured (see Fig. To measure the reaction time, one needs to find the time interval in which the accelerometer displays the acceleration value close to the value of I g i (or zero if you are using it in "acceleration without I g i " mode). [Extracted from the article]

The article focuses on the pedagogical concept of Doppler effect connecting to sources with constant accelerations for high school students. Topics discussed include explanation of the theory of Yukawa, description of effect for sound waves and one-dimensional kinematic model for Doppler effect. It presents information of mechanical model based on formulas of the effect.