Damped Oscillations – A smartphone approach

The study of the influence of geometric factors on an oscillating pendulum under various damping conditions is reported. Different cross-section areas perpendicular to the motion of the pendulum mass were studied. A smartphone was used as a pendulum and at the same time as a data recorder. Results show that the smartphone is an effective and reliable tool to be used when performing educational activities, and at the same time it presents students with a variety of ways for learning new content and physical concepts. It offers the opportunity to carry out experiments in the classroom, in the laboratory, or at home. In this way, the increment in the cross-section area slightly increases the damping coefficient, and rapidly decreases the oscillation amplitude as time passes. Additionally, the time necessary to decrease the amplitude by half is inversely proportional to the cross-section area of the pendulum. As expected, no significant variation in the period nor the angular frequency were found, due to the air-pendulum drag properties and to the slow pendulum speed.