Capítulo VII. Discovering the smartphone magnetometers of an experiment-based exam

Abstract

Conventionally, the final exam for the Laboratory of Electricity and Magnetism in the Physics Degree at the Universidad Complutense de Madrid consisted of a written exam, which was focused on replacing numerical values on equations that students should memorize. We consider this to be an outdated approach and have replaced this exam (for one call) with a practical problem that emphasizes the design of an experiment, comprehension of concepts, and the ability to apply them to real problems, rather than giving a higher weight to memory and arithmetic capabilities. We replaced this written exam with a practical problem that focused on experimental understanding and application of magnetic fields, the Hall Effect, the Biot-Savart Law, and the scientific method. The practical used sensors from a smartphone to design a "Biot-Savart" experiment that could be implemented during remote teaching scenarios. Students designed experiments, performed measurements, and presented their findings. The activity consisted of two major parts. The first part aimed to find the three magnetometers in the selected smartphone, assess the measurement range, and identify the measurement direction of each of them. The second part involved calculating the magnetic field generated by a single wire loop using the Biot-Savart Law, followed by constructing and measuring the loop. The activity evaluation graded the processes of design, measurement, and analysis, rather than the numerical outcome of each case. Moreover, it is not possible to expect students to have a current source at home; hence, the numerical outcome of the Biot-Savart law loses its relevance. This activity aimed to exercise the following abilities: teamwork, thinking and applying design, technological application (use of smartphones), and report writing (explaining the design and writing result reports). A survey of 100 students showed that 51% considered this methodology a better learning approach than the traditional written exam, and 75% found it more adapted to evaluate the targeted abilities. Despite the long activity, 56% of students received grades above 9.3 due to their correct application of concepts. This innovative methodology positively affected students' involvement and motivation for the learning process, and is a work in progress. We consider that this methodology constitutes an innovative procedure with room for improvement, which is positively received by the students, increasing their involvement and motivation for the learning process.