Simple Pendulum: Tracker x Phyphox

Abstract

Within didactical purposes, the measurement of the local gravitational constant using the Phyphox App method has no significant gain in accuracy when compared with the traditional method. To achieve this conclusion, an experiment in which the smartphone was used as a pendulum, running Phyphox, was filmed. The period of the movement was obtained from two independent sources: the data given by Phyhpox measurement and the video analysis, performed the software Traker. Then, a set up without the cellular was used to show the big influence of the human operator with a chronometer (traditional method) in comparison with the Traker methodology, which we believe is the most accurate. Moreover, in this case, it is possible to see an unexpected interesting behavior of the pendulum during approximately 24% of its periodic movement. The effect is so prominent that it became clear that, from a rigorous point of view, the simple pendulum mathematical model cannot be applied to all data we have in our tests.