Resumen de Physics Experiments Using an Automatically Controlled Model Train and Mobile Ultrasonic Sensor for a Smartphone
Here, I describe physics experiments using the motions of an automatically controlled model train. To measure these train motions, a mobile ultrasonic sensor unit (provided by Mobile Physics Education Lab1) was used. This sensor unit can be connected to a smartphone (Android OS) for display using a USB cable, and is convenient to carry. These experiments have been effective in stimulating interest in mechanics classes by providing a fun way for students to learn about motion through observation of a model train. It has been previously shown that mechanics concepts can be taught with RealTime Physics (RTP)using an Arduino-controlled electric model train and a smartphone-based ultrasonic motion sensor. The challenge has been producing smooth accelerations of the train, but I’ve solved that here.
In RTP by Sokoloff and collaborators, students predict what graphs of a motion will look like, and then compare their predictions to graphs produced from sensor-based measurements. It has been reported that this is an effective way to help students understand the concepts.2,3 I have previously reported physics experiments using an automatically controlled electric model train and a smartphone-based ultrasonic motion sensor. I used various constant-velocity linear motions with a model train, which can move in a more complex way than a standard dynamics cart or a fan-driven cart typically used in mechanics experiments.4,5 However, I had not been able to make the model train perform a constant-acceleration motion. Here, I was able to produce more complicated motions, including a constant-acceleration motion, by adjusting the applied voltage.
